At present, enzyme-linked immunosorbent assay (ELISA) is considered to be the most appropriate approach in clinical biomarker detection, with good specificity, low cost, and straightforward readout. However, unsatisfactory sensitivity severely hampers its wide application in clinical diagnosis. Herein, we designed a new kind of enhanced fluorescence enzyme-linked immunosorbent assay (FELISA) based on the human alpha-thrombin (HAT) triggering fluorescence “turn-on” signals. In this system, detection antibodies (Ab2) and HAT were labeled on the gold nanoparticles (AuNPs) to form the detection probes, and a bisamide derivative of Rhodamine110 with fluorescence quenched served as the substrate of HAT. After the sandwich immunoreaction, HAT on the sandwich structure could catalyze the cleavage of the fluorescence-quenched substrate, leading to a strong fluorescence signal for sensing ultralow levels of alpha fetoprotein (AFP) and hepatitis B virus surface antigen (HBsAg). Under the optimized reaction conditions, AFP and HBsAg were detected at the ultralow concentrations of 10–8 ng mL–1 and 5 × 10–4 IU mL–1, respectively, which were at least 104 times lower than those of the conventional fluorescence assay and 106 times lower than those of the conventional ELISA. In addition, we further discussed the efficiency of the sensitive FELISA in clinical serum samples, showing great potential in practical applications.Keywords: alpha fetoprotein; fluorescence enzyme-linked immunosorbent assay; gold nanoparticles; hepatitis B virus surface antigen; human alpha-thrombin;

To integrate multiple diagnostic and therapeutic strategies on a single particle through simple and effective methods is still challenging for nanotheranostics. Herein, we develop multifunctional nanotheranostic PB@Au core–satellite nanoparticles (CSNPs) based on Prussian blue nanoparticles (PBNPs) and gold nanoparticles (AuNPs), which are two kinds of intrinsic theranostic nanomaterials, for magnetic resonance (MR)–computed tomography (CT) imaging and synergistic photothermal and radiosensitive therapy (PTT–RT). PBNPs as cores enable T1- and T2-weighted MR contrast and strong photothermal effect, while AuNPs as satellites offer CT enhancement and radiosensitization. As revealed by both MR and CT imaging, CSNPs realized efficient tumor localization by passively targeted accumulation after intravenous injection. In vivo studies showed that CSNPs resulted in synergistic PTT–RT action to achieve almost entirely suppression of tumor growth without observable recurrence. Moreover, no obvious systemic toxicity of mice confirmed good biocompatibility of CSNPs. These results raise new possibilities for clinical nanotheranostics with multimodal diagnostic and therapeutic coalescent design.Keywords: gold nanoparticles; multimodal imaging; nanotheranostics; prussian blue nanoparticles; synergistic therapy;

Currently, protein/peptide-based biomimetic mineralization has been demonstrated to be an efficient and promising strategy for synthesis of inorganic/metal nanoparticles (NPs) for bioapplications. This strategy is found to be bio-inspired, straightforward, and environmentally benign. It can produce inorganic/metal NPs with good stability, excellent biocompatibility, high water solubility, and rich surface functional groups for further bioconjunction. In this review, we provide a summary of the previously reported proteins/peptides as biotemplates involved in biomimetic mineralization synthesis, and categorize the obtained inorganic NPs ranging from metal nanoclusters (MNCs), quantum dots (QDs), gadolinium derivatives, and metal sulfide nanoparticles (MSNPs) with an emphasis on the recent progress in their use in biomedical applications, including bio-sensing, ion detection, bio-labeling, in vivo imaging and therapy. In the end, the challenges and future outlook in this emerging area are also discussed.

Fluorescent signal-based lateral flow immunochromatographic strips (FLFICS) have received great expectations since they effectively improve detection sensitivity with quantitative analysis, and still retain the advantages of simplicity, rapidness, and portability of a common lateral flow immunochromatographic strip (LFICS). Diverse fluorescent reporters have promoted development of FLFICS, such as fluorescent dyes, quantum dots (QDs), an up-converting phosphor (UCP), lanthanide labels, and other fluorescence nanoparticles. In this work, we discuss the different fluorescent reporters applied with LFICS and their unique properties as well as signal amplification strategies helping to enhance detection performance. Benefitting from these sensitive and accurate fluorescent labels, FLFICS commendably satisfies requirements for detecting different disease biomarkers in medical diagnosis, strict supervision of food safety, and water pollution. This work also gives a short introduction to trends in the development of future FLFICS technology.

Cataract is a major cause of visual impairment for diabetic patients. It is imperative to develop efficient therapeutic agents against diabetic cataract (DC) because diabetes confers higher risk for complications after cataract surgery. We have previously reported the role of CeCl3 loaded mesoporous silica (CeCl3@mSiO2) nanoparticles in reducing the oxidative stress of lens epithelial cells. However, the potential of CeCl3@mSiO2 in preventing diabetic cataract development remains unclear. In this study, we applied CeCl3@mSiO2 nanoparticles with a size of 87.6 ± 8.9 nm to streptozotocin-induced diabetic cataract rat model by intraperitoneal injection. Our results showed that CeCl3@mSiO2 efficiently ameliorated the progression of DC. Consistent with antioxidant effect of CeCl3@mSiO2in vitro, administration of CeCl3@mSiO2 significantly abrogated hyperglycemia-mediated upregulation of advanced glycation end products, lipid peroxidation and protein carbonylation in animal lens. Taken together, our study provides a potential nanodrug to manage the development of DC.In this work, we design a kind of cerium (III) chloride (CeCl3) loaded mesoporous silica (CeCl3@mSiO2) nanoparticles and proved their potential application in preventing the formation of diabetic cataract in vitro and vivo by using a well-established rat model of STZ-induced diabetes. A: the schematic diagram of CeCl3@mSiO2 nanoparticles preparation; B: TEM of mSiO2 nanoparticles (local enlargement of single mSiO2 nanoparticles); C: A line graph, showing the time course of changes cataract degrees in different groups of animals; D: various degrees of cataract and representative images of H&E-stained sections of the lens tissue in experimentally diabetic animals 8 weeks after treatment with vehicle, 10 mg/kg and 20 mg/kg CeCl3@mSiO2 nanoparticles, respectively.Download high-res image (200KB)Download full-size image

•The photothermal therapy is a good way to treat tumors.•The ICG@mZGC nanoparticles could lower signal-to-noise ratio when imaging.•This system can realize visual accurate PTT.•ICG@mZGC performs a good effect of photothermal therapy in vivo.The photothermal therapy agents induced by 808 nm near infrared light laser have good potential for photothermal therapy (PTT) in vivo, with the advantages of harmless treatment, minimally invasion, high efficiency and deep tissue penetration. For the traditional photothermal therapy agents, however, it was impossible to track them in vivo because of the low signal-to-noise ratio, so we cannot conduct the extra near infrared light laser to radiate tumors sites accurately. Herein, we introduce a new complex: indocyanine green (ICG), near-infrared persistent luminescence (PL) phosphors ZnGa2O4:Cr3 + (ZGC) and mesoporous silica nanoparticles (MSNs) (ICG@mZGC nanoparticles) were assembled for long-lasting optical imaging to guide PTT. The results revealed that the novel nanoparticle, ICG@mZGC, could lower signal-to-noise ratio, enable highly sensitive optical detection during optical imaging-guided PTT and perform a good effect of photothermal therapy in vivo, and thus providing possibilities for mZGC to improve the localization precision of tumor sites in photothermal therapy in the body.

Combination of gene therapy and photothermal therapy (PTT) has drawn much attention in cancer therapy in recent years. However, this joint treatment process lacks fluorescence imaging visualization guidance that limits its clinical applications in oncotherapy. Herein, we report the use of gene therapy and tungsten oxide (W18O49, WO) synthetized with template method for combined PTT of cancer. In this system, a novel nanoplatform, with Bax gene, WO and indocyanine green (ICG) loaded in mesoporous silica nanoparticle had been successfully constructed, which was used as the near-infrared imaging-guided gene/optothermal multi-modal oncotherapy. These nanoparticles could achieve a synergistic therapy effect of gene therapy and PTT for tumor under 808 nm near-infrared (NIR) laser excitation. In vivo animal experiments showed that they could cause solid tumor regression under 808 nm NIR light irradiation, revealing the potential of these nanocomposites as a fluorescence imaging-guided multi-modal therapeutic nanosystem for tumor visual synergistic treatment.Download high-res image (135KB)Download full-size image

At present, many researchers focused on the point-of-care testing (POCT), a method of disease markers detection without large-scale instruments and specialized persons. However, most POCT diagnostic methods were suffered from poor detection sensitivity or inefficiency in quantitative detection. Herein, we developed a newly QD-immune fluorescence test strips (QD-IFTS) based on quantum dots (QDs) as the fluorescence nanocarrier to prepare the immune fluorescence probes in the classical immunochromatography detection system for sensing carcino-embryonic antigen (CEA), a kind of glycoprotein produced by intestinal tissue and a broad spectrum of tumor marker for cancer diagnosis. And we designed a homemade strips fluorescence reader for detection of fluorescence intensity of QDs on the QD-IFTS. Under the optimized reaction conditions, chromatographic time of the newly QD-IFTS was only 25 min, sample volume of the newly QD-IFTS was only 40 μL and the LOD of the newly QD-IFTS was 0.72 ng/mL. In addition, the efficiency and robustness of the newly QD-IFTS were confirmed by successfully application in 300 clinical serum samples, and the results revealed great potential in clinical POCT of other biomarkers.Download high-res image (123KB)Download full-size imageA QDs-based immune fluorescence test strips was built up for carcino-embryonic antigen detection to realize cancers POCT diagnostic, with a sensitivity of 0.72 ng/mL in 25 min.

•A novel gene detection microplatform for one-step detecting TK1-DNA and microRNA-21 was constructed.•The microplatform used NSET microbeads as nucleic acid probes.•The detection platform could detect the nucleic acid with high throughput, high sensitivity and high specificity.Microbeads-based microchip technology has become the potential for a new generation of nucleic acids detection in a high-throughput and sensitive manner. However the specificity and operational complexity limit the microchip applied in nucleic acids detection. Herein, in this work, we designed a kind of gold-nanoparticles coated polystyrene microbeads as microplatform conjugating with the molecular beacons as probes. Due to the nanoparticle surface energy transfer of gold-nanoparticles, the fluorescence of dye on one end of molecular beacons was effectively quenched. When the target nucleic acids existed, the fluorescence of dye was quickly “turn-on” with high sensitivity. Due to the nanoparticle surface energy transfer effect of gold-nanoparticles, the designed platform performed better sensitivity than traditional microbead-based detection methods and realized quickly detection within 10 min without purification steps. In addition, compared with the linear chain probes, the molecular beacons probes enabled higher specificity and wash-free operation. Through different dyes encoded, TK1-DNA and microRNA-21 were simultaneously detected in one step and finally quantified by flow cytometry. The proposed detection method was also capable of monitoring TK1-DNA and microRNA-21 levels in human serum. Our study provides the potential multidetection of DNA and RNA.

Recently, immunochromatography test strips (ICTS) have been fully developed for point-of-care testing (POCT). However, the intrinsic limitations including non-quantitative detection of colloidal gold ICTS and low sensitivity of fluorescence ICTS (FICTS) significantly restrict their further application in clinical diagnosis. Taking advantages of rapid colorimetric qualitative detection and fluorescence quantitation, we designed a kind of sensitive and dual-mode magnetic FICTS (mFICTS) based on PLGA@Fe3O4 super-paramagnetic nanosphere (SPMN) probes quenching multiplex fluorescer on the test line through sandwich immunoreactions. Owing to the large number of Fe3O4 nanoparticles (about 47) encapsulated in one SPMN, about 2680 Cy5 molecules were quenched by one SPMN on the test line such that to significantly improve the analytical sensitivity as well as the detection of whole blood samples via magnetic separation. Moreover, the aggregation of black SPMN on the test line enabled a quick naked-eye screening in 3 min. For high accuracy breast cancer diagnosis, combined determination of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA153) was performed on one mFICTS with the limits of detection of about 0.06 ng mL−1 and 0.09 U mL−1, respectively. Then, more than 50 clinical serum samples were investigated for high-resolution screening by mFICTS, and the results were coincident with those obtained by electrochemiluminescence immunoassay (ECLIA). Thus, the designed mFICTS is suitable for point-of-care diagnostics.

Sensitive and specific fluorescence imaging-guided photothermal therapy (PTT) with high-efficiency is of essential importance and is still a challenge for nanotheranostics. To address these issues, we developed activatable ultrasmall gold nanorods (AUGNRs) to realize “off–on” switched fluorescence imaging-guided efficient PTT. Herein, the GNRs with an ultrasmall small size (∼4 nm) were set as the PTT platform due to their distinct absorption-dominant characteristics, generating an enhanced photothermal conversion efficiency. A near infrared (NIR) dye, Cy5, was conjugated to the surface of the ultrasmall GNRs for fluorescence imaging. Due to the strong localized surface plasmon resonance (LSPR), the fluorescence of Cy5 could be remarkably quenched by the GNRs and show an “off” state under normal conditions. As the AUGNRs are internalized by tumor cells, their ability of fluorescence imaging would be activated by glutathione (GSH) for the reducing action of GSH. Given the higher intracellular GSH concentration in tumor cells, a highly selective intracellular fluorescence imaging pattern was provided by the AUGNRs. As a result, the obtained AUGNRs revealed a uniformly rod-like structure with an aspect ratio of ∼4 and showed an enhanced photothermal conversion efficiency. The in vitro cellular uptake study indicated that the AUGNRs can efficiently enter the tumor cells. It has been demonstrated by in vitro Cy5 release profiles that the AUGNRs could achieve a triggered Cy5 release in response to GSH. The MTT assay and calcein AM/PI co-staining demonstrated that the cancer cells could be effectively killed when exposed to a NIR laser. Our work presents great potential for activated fluorescence imaging-guided PTT with high specificity and efficiency, as a promising method for future clinical cancer diagnostics and treatment.

Ultrasensitive and quantitative fast screening of cancer biomarkers by immunochromatography test strip (ICTS) is still challenging in clinic. The gold nanoparticles (NPs) based ICTS with colorimetric readout enables a quick spectrum screening but suffers from nonquantitative performance; although ICTS with fluorescence readout (FICTS) allows quantitative detection, its sensitivity still deserves more efforts and attentions. In this work, by taking advantages of colorimetric ICTS and FICTS, we described a reverse fluorescence enhancement ICTS (rFICTS) with bimodal signal readout for ultrasensitive and quantitative fast screening of carcinoembryonic antigen (CEA). In the presence of target, gold NPs aggregation in T line induced colorimetric readout, allowing on-the-spot spectrum screening in 10 min by naked eye. Meanwhile, the reverse fluorescence enhancement signal enabled more accurately quantitative detection with better sensitivity (5.89 pg/mL for CEA), which is more than 2 orders of magnitude lower than that of the conventional FICTS. The accuracy and stability of the rFICTS were investigated with more than 100 clinical serum samples for large-scale screening. Furthermore, this rFICTS also realized postoperative monitoring by detecting CEA in a patient with colon cancer and comparing with CT imaging diagnosis. These results indicated this rFICTS is particularly suitable for point-of-care (POC) diagnostics in both resource-rich and resource-limited settings.Keywords: bimodal signal readout; carcinoembryonic antigen (CEA); POCT; postoperative monitoring; reverse fluorescence enhancement ICTS (rFICTS)

Optical imaging-guidance of indocyanine green (ICG) for photothermal therapy (PTT) has great latent capacity in cancer therapy. However, the conventional optical image-guidance mode has caused strong tissue autofluorescence of the living tissue, which leads to the accurate infrared light irradiation cannot be conducted. In this article, ICG and persistent luminescence phosphors (PLPs) coloaded mesoporous silica nanocarriers ((ICG+PLPs)@mSiO2) were first designed and prepared for persistent luminescent imaging-guided PTT. The (ICG+PLPs)@mSiO2 nanocarriers could significantly improve signal-to-noise ratio during luminescence imaging-guided PTT, making the PLP promising for improving the accuracy of the tumor site for photothermal therapy in vivo. This paper is likely to develop a new way for accurately regulating cancer cell death based on luminescence imaging-guided PTT selectively triggered by near-infrared (NIR)-remote.Keywords: indocyanine green (ICG); luminescent nanoprobes; near-infrared light (NIR); persistent luminescence phosphors (PLPs); photothermal therapy (PTT)

Immunoassays based on the downconversion target materials (organic dyes or quantum dots) lead to fairly strong spectral interference between the coded signal and reporter signal, which seriously affects the detection accuracy and hampers their applications. In this work, a new kind of upconverting nanocrystals encoded magnetic microspheres (UCNMMs) were designed and prepared successfully to solve the problem mentioned above. The UCNMMs were obtained by incorporating magnetic Fe3O4 nanoparticles and upconverting nanocrystals with polystyrene microspheres. Due to that upconverting nanocrystals (UCNs) and reporter signals are excitated by near-infrared and UV/visible light separately, immunoassays based on UCNMMs do not occur optical spectral interferences. Furthermore, these new functionalized UCNMMs have excellent properties in binding biomolecules and fast separating, which would have large potential applications in multiplexed assays.Keywords: double-antibody sandwich immunoassay; fast immunoassay; magnetic nanoparticles; multifunctional microspheres; upconverting nanocrystals

•A novel strategy combined the high temperature with chemical swelling technology is designed.•Based on hydrophobic interaction and polymer thermal motion, QDs and Fe3O4 were effectively packaged into microbeads.•The fluorescence-encoded magnetic microbeads show long-term fluorescent encoding and immunodetection stability.Fluorescence-encoded magnetic microbeads (FEMMs), with the fluorescence encoding ability of quantum dots (QDs) and magnetic enrichment and separation functions of Fe3O4 nanoparticles, have been widely used for multiple biomolecular detection as microfluidic protein chip supports. However, the preparation of FEMMs with long-term fluorescent encoding and immunodetection stability is still a challenge. In this work, we designed a novel high-temperature chemical swelling strategy. The QDs and Fe3O4 nanoparticles were effectively packaged into microbeads via the thermal motion of the polymer chains and the hydrophobic interaction between the nanoparticles and microbeads. The FEMMs obtained a highly uniform fluorescent property and long-term encoding and immunodetection stability and could be quickly magnetically separated and enriched. Then, the QD-encoded magnetic microbeads were applied to alpha fetoprotein (AFP) detection via sandwich immunoreaction. The properties of the encoded microspheres were characterized using a self-designed detecting apparatus, and the target molecular concentration in the sample was also quantified. The results suggested that the high-performance FEMMs have great potential in the field of biomolecular detection.We designed a novel strategy to prepare a kind of high-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip support with long-time fluorescent encoding and immunodetection stability for AFP detection.

•We developed a simple system for Fe3+ and Cu2+ sensing with low cost and easy operations.•Fe3+ and Cu2+ are simultaneously detected via colorimetric readout and fluorescent absorbance signals.•The sensor realized the simultaneously detection of Fe3+ and Cu2+ successively with highly sensitivity and selectivity.Here, we report an ultra-sensitive and colorimetric sensor for the detection of Fe3+ or Cu2+ successively using glutathione-functionalized Au nanoclusters (GSH-AuNCs). For GSH-AuNCs can catalytically oxidize peroxidase substrates, such as 3, 3′, 5, 5′-tetramethylbenzidine (TMB), colored products are formed in the presence of H2O2. While upon the addition of Fe3+ or Cu2+ into the GSH-AuNCs-TMB-H2O2 system, diverse color and absorbance of the system was obtained due to the self oxidation of Fe3+ and the inhibition of peroxidase-like activity of GSH-AuNCs. With the introduction of ethylene diamine tetraacetic acid (EDTA) or ammonium fluoride (NH4F) to GSH-AuNCs-TMB-H2O2+Cu2+ system or GSH-AuNCs-TMB-H2O2+Fe3+ system respectively, a restoration of color and absorbance of system was realized. On the basis of above phenomenon, a colorimetric and quantitative approach for detecting Fe3+ and Cu2+ was developed with detection limit of 1.25 × 10−9 M and 1.25 × 10−10 M respectively. Moreover, the concentration of Fe3+ and Cu2+ in human serums was also accurate quantified by this method. So this design strategy realized the simple and simultaneous detection of Fe3+ and Cu2+, suggesting significant potential in clinical diagnosis.We designed a novel strategy for the colorimetric and sensitive detection of Fe3+ and Cu2+ based on the peroxidase-like activity of GSH-AuNCs.

Photothermal therapy (PTT) is attracting increasing interest and becoming more widely used for skin cancer therapy in the clinic, as a result of its noninvasiveness and low systemic adverse effects. However, there is an urgent need to develop biocompatible PTT agents, which enable accurate imaging, monitoring, and diagnosis. Herein, a biocompatible Gd-integrated CuS nanotheranostic agent (Gd:CuS@BSA) was synthesized via a facile and environmentally friendly biomimetic strategy, using bovine serum albumin (BSA) as a biotemplate at physiological temperature. The as-prepared Gd:CuS@BSA nanoparticles (NPs) with ultrasmall sizes (ca. 9 nm) exhibited high photothermal conversion efficiency and good photostability under near-infrared (NIR) laser irradiation. With doped Gd species and strong tunable NIR absorbance, Gd:CuS@BSA NPs demonstrate prominent tumor-contrasted imaging performance both on the photoacoustic and magnetic resonance imaging modalities. The subsequent Gd:CuS@BSA-mediated PTT result shows high therapy efficacy as a result of their potent NIR absorption and high photothermal conversion efficiency. The immune response triggered by Gd:CuS@BSA-mediated PTT is preliminarily explored. In addition, toxicity studies in vitro and in vivo verify that Gd:CuS@BSA NPs qualify as biocompatible agents. A biodistribution study demonstrated that the NPs can undergo hepatic clearance from the body. This study highlights the practicality and versatility of albumin-mediated biomimetic mineralization of a nanotheranostic agent and also suggests that bioinspired Gd:CuS@BSA NPs possess promising imaging guidance and effective tumor ablation properties, with high spatial resolution and deep tissue penetration.Keywords: biomimetic mineralization; CuS; MR imaging; photoacoustic; photothermal therapy

Many theranostic nanomedicines (NMs) have been fabricated by packaging imaging and therapeutic moieties together. However, concerns about their potential architecture instability and pharmacokinetic complexity remain major obstacles to their clinical translation. Herein, we demonstrated the use of CuInS/ZnS quantum dots (ZCIS QDs) as “all-in-one” theranostic nanomedicines that possess intrinsic imaging and therapeutic capabilities within a well-defined nanostructure. ZCIS QDs were exploited for multispectral optical tomography (MSOT) imaging and synergistic PTT/PDT therapy. Due to the intrinsic fluorescence/MSOT imaging ability of the ZCIS QDs, their size-dependent distribution profiles were successfully visualized at tumor sites in vivo. Our results showed that the smaller nanomedicines (ZCIS NMs-25) have longer tumor retention times, higher tumor uptake, and deeper tumor penetration than the larger nanomedicines (ZCIS NMs-80). The ability of ZCIS QDs to mediate photoinduced tumor ablation was also explored. Our results verified that under a single 660 nm laser irradiation, the ZCIS NMs had simultaneous inherent photothermal and photodynamic effects, resulting in high therapy efficacy against tumors. In summary, the ZCIS QDs as “all-in-one” versatile nanomedicines allow high therapeutic efficacy as well as noninvasively monitoring tumor site localization profiles by imaging techniques and thus hold great potential as precision theranostic nanomedicines.Keywords: CuInS/ZnS quantum dots; multispectral optical tomography; photoacoustic imaging; photodynamic therapy; photothermal therapy

Combined cancer therapy possesses many advantages including improved tumoricidal efficacy, reduced side effects, and retarded drug resistance. Herein, a protein–polymer bioconjugate-coated multifunctional upconversion nanosystem, consisting of upconversion nanoparticles (UCNs) core, tailored amphiphilic protein–polymer bioconjugate shell, and photosensitizer zinc phthalocyanine (ZnPc) and antitumor drug doxorubicin coloaded inside, was elaborately developed for combined photodynamic therapy (PDT) and chemotherapy. In this system, UCNs core could convert deep penetrating near-infrared light to visible light for simultaneous cell fluorescence imaging and photodynamic therapy by activating ZnPc to generate cytotoxic ROS, while the protective shell of bovine serum albumin–poly(ε-caprolactone) (BSA-PCL) offered excellent water solubility, good stability, and low cytotoxicity. The ROS production test showed that this nanosystem could successfully generate singlet oxygen under NIR irradiation. A cellular uptake study demonstrated that intense fluorescence emission of the UCNs could be observed in HeLa cells, indicating their outstanding real-time imaging capability. More importantly, compared with single PDT or chemotherapy systems, the constructed combined therapy UCNs system demonstrated significantly enhanced tumor cell killing efficiency. On the basis of our findings, this multifunctional UCNs nanosystem could be a promising versatile theranostic nanoplatform for image-guided combined cancer therapy.Keywords: chemotherapy; combined therapy; photodynamic therapy; protein−polymer bioconjugate; upconversion nanosystems;

Computed tomography (CT) contrast and radiosensitization usually increase with particle sizes of gold nanoparticles (AuNPs), but there is a huge challenge to improve both by adjusting sizes under the requirements of in vivo application. Here, we report that AuNPs have great size-dependent enhancements on CT imaging as well as radiotherapy (RT) in the size range of 3–50 nm. It is demonstrated that AuNPs with a size of ∼13 nm could simultaneously possess superior CT contrast ability and significant radioactive disruption. The Monte Carlo method is further used to evaluate this phenomenon and indicates that the inhomogeneity of gold atom distributions caused by sizes may influence secondary ionization in whole X-ray interactions. In vivo studies further indicate that this optimally sized AuNP improves real-time CT imaging and radiotherapeutic inhibition of tumors in living mice by effective accumulation at tumors with prolonged in vivo circulation times compared to clinically used small-molecule agents. These results suggest that ∼13 nm AuNPs may serve as multifunctional adjuvants for clinical X-ray theranostic application.Keywords: AuNPs; CT imaging; Monte Carlo simulations; radiosensitization; size-tuning ionization; X-ray theranostics;

Various nanoparticles have been employed for gene delivery. Revealing the endocytosis or phagocytosis behaviors of the gene delivery system is critical for designing sophisticated gene therapies. Herein, a kind of water-soluble PEI capped AgInS/ZnS (ZAIS@PEI) quantum dot was synthesized as a self-indicating gene vector in the presence of branched polyethylenimine (PEI) and mercaptopropionic acid (MPA). The as-prepared ZAIS@PEI QDs could efficiently condense plasmid DNA into nanocomplexes with strong fluorescence, which can reveal their positions during gene transfection. Our results confirmed that ZAIS@PEI could mediate plasmid DNA delivery into HeLa cells with the high transfection efficiency of 40% and low cytotoxicity, meanwhile allowing the real-time monitoring of gene transfection. The obtained ZAIS@PEI QDs were verified as versatile self-tracking gene vectors, which integrated gene delivery with bioimaging functions without external labeling.

In clinics, the application of photodynamic therapy (PDT) in deep tissue is severely constrained by the limited penetration depth of visible light that was used for activating the photosensitizer (PS). In this work, a protocol of a UCN@SiO2@crosslinked lipid triple layer nanoparticle was developed successfully. The triple layer nanoparticle was assembled from the hydrophobic upconverting nanoparticle (UCN) core, the mesoporous silica middle shell and the cross-linked lipid out shell. The photosensitizer zinc phthalocyanine (ZnPc) loaded triple layer nanoparticle offers possibilities to solve the problem mentioned above. The UCN core works as a transducer to convert deeply penetrating near infrared light to visible light for activating ZnPc for photo dynamic therapy. The middle shell is used for loading ZnPc and the out shell can prevent the drug leaking effectively. The experiment results showed that with the help of the cross-linked lipid shell, the triple layer nanoparticle could prevent the drug leaking and particle aggregation. The ROS production test and PDT test suggested that the fluorescence emitted from the UCNs excited by NIR can effectively activate the photosensitizer ZnPc to generate cytotoxic ROS. The UCN@SiO2@crosslinked lipid triple layer nanoparticle modified with RGD has a much better treatment effect in cancer cells. Our data suggest that the UCN@SiO2@crosslinked lipid triple layer nanoparticle may be a useful nanoplatform for future PDT treatment in deep cancer therapy based on the upconverting mechanism.

Dual-modal imaging techniques have gained intense attention for their potential role in the dawning era of tumor early accurate diagnosis. Chelate-free robust dual-modal imaging nanoprobes with high efficiency and low toxicity are of essential importance for tumor targeted dual-modal in vivo imaging. It is still a crucial issue to endow Cd-free dual-modal nanoprobes with bright fluorescence as well as high relaxivity. Herein, a facile synthetic strategy was developed to prepare Gd-doped CuInS/ZnS bimodal quantum dots (GCIS/ZnS, BQDs) with optimized properties. The fluorescent properties of the GCIS/ZnS BQDs can be thoroughly optimized by varying reaction temperature, aging time, and ZnS coating. The amount of Gd precursor can be well-controlled to realize the optimized balance between the MR relaxivity and optical properties. The obtained hydrophobic GCIS/ZnS BQDs were surface engineered into aqueous phase with PEGylated dextran-stearyl acid polymeric lipid vesicles (PEG-DS PLVs). Upon the phase transfer, the hydrophilic GCIS/ZnS@PLVs exhibited pronounced near-infrared fluorescence as well as high longitudinal relaxivity (r1 = 9.45 mM–1 S–1) in water with good colloidal stability. In vivo tumor-bearing animal experiments further verified GCIS/ZnS@PLVs could achieve tumor-targeted MR/fluorescence dual-modal imaging. No toxicity was observed in the in vivo and ex vivo experiments. The GCIS/ZnS@PLVs present great potential as bimodal imaging contrast agents for tumor diagnosis.Keywords: dual-modal imaging; fluorescence imaging; MRI; quantum dots; targeted imaging

Inspired by the specificity of acid tumor microenvironment, we constructed a flexible charge-reversible near-infrared (NIR) fluorescence nanoprobe in response to tumor extracellular pH (pHe) for effective tumor-specific imaging. The nanoprobe consists of an NIR-emitted CuInS2/ZnS quantum dot (CIS/ZS QDs) core and a tailored lauric acid and 2,3-dimethylmaleic anhydride modified ε-polylysine (ε-PL-g-LA/DMA) shell, which provides not only a dense protective layer for the QDs but also the ability of pHe-induced positive charge-mediated endocytosis into tumor cells. The results showed that the QDs@ε-PL-g-LA/DMA nanoprobe with a uniform size of 40 nm had high chemical stability at pH 7.4 and excellent optical properties. Especially, it swiftly reversed its surface charge to positive in 20 min when exposed to pHe due to the cleavage of the β-carboxyl amide bond of ε-PL-g-LA/DMA. Moreover, the cell uptake of the pHe-sensitive QDs nanoprobe exposed at pH 6.8 into HeLa cells is much more significant than that at pH 7.4, which further verified the availability of the electrostatic adsorptive endocytosis facilitated targeting ability. The pHe-induced targeting imparted the QDs nanoprobe a broad targeting ability in a variety of solid tumors. Furthermore, as an effective alternative mechanism for tumor targeting, responsive charge reversion is also universally applicable to other cancer theranostics agent.Keywords: charge reversion; pH-sensitive; QDs nanoprobe; tumor extracellular pH; tumor-specific imaging;

A simple, straightforward, and reproducible strategy for the construction of a near-infrared (NIR) fluorescence nanoprobe was developed by coating CuInS2/ZnS quantum dots (CIS/ZnS QDs) with a novel amphiphilic bioconjugate. The amphiphilic bioconjugate with a tailor-designed structure of bovine serum albumin (BSA) as the hydrophilic segment and poly(ε-caprolactone) (PCL) as the hydrophobic part was fabricated by chemical coupling the hydrophobic polymer chain to BSA via the maleimide–sulfhydryl reaction. By incorporating CIS/ZnS QDs into the hydrophobic cores of the self-assembly of BSA-PCL conjugate, the constructed NIR fluorescence nanoprobe exhibited excellent fluorescent properties over a wide pH range (pH 3–10) and a good colloidal stability in PBS buffer (pH = 7.4) with or without 10% fetal bovine serum. The presence of the outer BSA shell effectively reduced the nonspecific cellular binding and imparted high biocompatibility and low-toxicity to the probe. Moreover, the NIR fluorescence nanoprobe could be functionalized by conjugating cyclic Arg-Gly-Asp (cRGD) peptide, and the decorated nanoprobe was shown to be highly selective for targeted integrin αvβ3-overexpressed tumor cell imaging. The feasibility of the constructed NIR fluorescence probe in vivo application was further investigated and the results demonstrated its great potential for in vivo imaging. This developed protocol for phase transfer of the CIS/ZnS QDs was universal and applicable to other nanoparticles stabilized with hydrophobic ligands.Keywords: BSA; CuInS2/ZnS quantum dots; fluorescence nanoprobe; protein-polymer conjugate; self-assembly

A smart pH-responsive photodynamic therapy system based on upconversion nanoparticle loaded PEG coated polymeric lipid vesicles (RB-UPPLVs) was designed and prepared. These RB-UPPLVs which are promising agents for deep cancer photodynamic therapy applications can achieve enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.

MHC II transactivator (CII TA) protein is a requisite for the expression of major histocompatibility complex class II (MHC II) proteins which are principal mediators of immune response. Construction of an effective nanocomplex to suppress expression of CII TA proteins can be a potential strategy for inhibiting unwanted immune response. In this work, a nanocomplex was designed by incorporating pCIITA (CII TA genes within a plasmid) into the polycationic liposomes with an optimal mass ratio at 1:2. The monodisperse nanocomplexes possessed spherical shape and uniform size. Results of cells transfection showed that the nanocomplexes displayed an enhanced ability of intracellular delivery than that of naked pCIITA. Expression of CII TA and MHC II proteins were significantly decreased in the transfected cells. Furthermore, the in vitro immune response model based on mixed lymphocyte culture experiment confirmed that the nanocomplexes successfully inhibited immune response of dendritic cells (DCs) through intracellular delivery of CIITA genes. All the results suggested this approach has a great potential in suppression of unwanted immune responses, which relates to many immune diseases.

Functionalized quantum dots (QDs) have been widely explored for multimodality bioimaging and proven to be versatile agents. Attaching positron-emitting radioisotopes onto QDs not only endows their positron emission tomography (PET) functionality, but also results in self-illuminating QDs, with no need for an external light source, by Cerenkov resonance energy transfer (CRET). Traditional chelation methods have been used to incorporate the radionuclide, but these methods are compromised by the potential for loss of radionuclide due to cleavage of the linker between particle and chelator, decomplexation of the metal, and possible altered pharmacokinetics of nanomaterials. Herein, we described a straightforward synthesis of intrinsically radioactive [64Cu]CuInS/ZnS QDs by directly incorporating 64Cu into CuInS/ZnS nanostructure with 64CuCl2 as synthesis precursor. The [64Cu]CuInS/ZnS QDs demonstrated excellent radiochemical stability with less than 3% free 64Cu detected even after exposure to serum containing EDTA (5 mM) for 24 h. PEGylation can be achieved in situ during synthesis, and the PEGylated radioactive QDs showed high tumor uptake (10.8% ID/g) in a U87MG mouse xenograft model. CRET efficiency was studied as a function of concentration and 64Cu radioactivity concentration. These [64Cu]CuInS/ZnS QDs were successfully applied as an efficient PET/self-illuminating luminescence in vivo imaging agents.Keywords: CRET; CuInS/ZnS; dual-modality imaging; PET imaging; quantum dots;

Conventional liposomes (CLs) have been used as a transdermal drug delivery system for enhancing the delivery of hydrophilic drugs into/through the skin. However, their applications have been constrained by their limited penetration ability and poor stability. In this article, a new kind of transactivating transcriptional activator peptide (TAT)-conjugated polymeric lipid vesicles (TPLVs) formed from amphiphilic lysine–linoleic acid modified dextran (LLD) and cholesterol (Chol) has been prepared successfully. The newly developed TPLVs had a bilayer structure similar to CLs. The TPLVs also have smaller particle size, narrower distribution, higher positive charge and much better stability than the CLs; they remained stable in aqueous solutions for up to 60 days without aggregation. The in vitro and in vivo skin permeation studies revealed that TPLVs delivered a higher amount of drug through the skin than CLs, indicating enhanced drug transdermal activities. The synergetic effects of abovementioned features and the cell-penetrating peptide TAT might have contributed to the improved skin penetration ability of the TPLVs. Similar to CLs, TPLVs began to show limited cytotoxicity against human umbilical vein endothelial cells at a concentration of 200 μg mL−1. The in vitro release profiles showed that the TPLVs achieved a sustained release of lidocaine. These results suggest that the TPLVs may be utilized as an efficient carrier to replace CLs for transdermal drug delivery.

To improve their therapeutic index, designed nanocarriers should preferentially accumulate in tumor tissues and then rapidly enter tumor cells to release the encapsulated drugs in a triggered manner. In this article, a new kind of a smart pH- and reduction-dual-responsive drug delivery system based on folate–PEG-coated polymeric lipid vesicles (FPPLVs) formed from amphiphilic dextran derivatives was designed and prepared successfully. PEG chains with pH-sensitive hydrazone bonds, stearyl alcohol (SA) chains with reduction-sensitive disulfide bonds and folate were connected to a dextran main chain. The newly developed FPPLVs had a nano-sized structure (∼50 nm) with a PEG coating. The in vitro DOX release profiles showed that the FPPLVs achieved a triggered drug release in response to acidic pH and reducing environments due to the cleavage of hydrazone bonds and disulfide bonds. It has also been demonstrated by an in vitro cellular uptake study that the FPPLVs lose their PEG coating as well as expose the folate in acidic conditions, which allows them to efficiently enter tumor cells through ligand–receptor interactions. In vitro cytotoxicity measurements also confirmed that FPPLVs exhibited pronounced antitumor activity against HeLa cells. These results suggest that FPPLVs are promising carriers for smart antitumor drug delivery applications.

Self-assembled nanostructures based on amphiphilic protein–polymer conjugates have shown great advantages in the field of nanomedicine such as inherent biocompatibility with biosystems because of their excellent performance. Herein, a novel biodegradable protein–polymer conjugate was prepared by covalently linking the tailor-made hydrophobic maleimide-functionalized poly(ε-caprolactone) (PCL) to hydrophilic bovine serum albumin (BSA) via the maleimide–sulfhydryl coupling reaction. This protein-based conjugate with a biodegradable polyester was reported for the first time, and the obtained biohybrid displayed well-defined structure, excellent biocompatibility and low cytotoxicity, and self-assembly behaviors similar to those of the traditional amphiphilic small molecules and block copolymers. The amphiphilic BSA–PCL conjugate can self-assemble into a nanosized vesicle with a negative surface charge. Furthermore, the self-assembled vesicle based on the BSA–PCL conjugate was functionalized via linking targeting ligand cetuximab to its surface to enhance cell uptake, and the doxorubicin (DOX)-encapsulated cetuximab-functionalized vesicle exhibited enhanced antitumor activity compared with that of free DOX in vitro. These results indicate that the biodegradable protein–polymer conjugate based on BSA and PCL had great potential as a drug delivery vehicle for cancer therapy.Keywords: bovine serum albumin; nanocarrier; poly(ε-caprolactone); protein−polymer conjugate; self-assembly;

In clinic, the application of photodynamic therapy (PDT) in deep tissue is severely constrained by the limited penetration depth of visible light needed for activating the photosensitizer (PS). In this Article, a merocyanine 540 (MC540) and upconverting nanoparticle (UCN) coloaded functional polymeric liposome nanocarrier, (MC540 + UCN)/FPL, was designed and constructed successfully for solving this problem in PDT. Compared with the conventional approaches using UCNs absorbing PSs directly, the combination of UCN and polymeric liposome has unique advantages. The UCN core as a transducer can convert deep-penetrating near-infrared light to visible light for activating MC540. The functional polymeric liposome shell decorated with folate as a nanoshield can keep the UCN and MC540 stable, protect them from being attacked, and help them get into cells. The results show that (MC540 + UCN)/FPL is an individual nanosphere with an average size of 26 nm. MC540 can be activated to produce singlet oxygen successfully by upconverting fluorescence emitted from UCNs. After (MC540 + UCN)/FPL was modified with folate, the cell uptake efficiency increased obviously. More interestingly, in the PDT effect test, the (MC540 + UCN)/FPL nanocarrier further improved the inhibition effect on tumor cells by anchoring targeting folate and transactivating transduction peptide. Our data suggest that the (MC540 + UCN)/FPL nanocarrier may be a useful nanoplatform for future PDT treatment in deep-cancer therapy based on upconversion mechanism.Keywords: MC540; nanocrystal; near-infrared light; photodynamic therapy; polymeric liposome; upconverting;

Convenient and fast testing using an immunochromatography test strip (ICTS) enables rapid yes/no decisions regarding a disease to be made. However, the fundamental limitations of an ICTS, such as a lack of quantitative and sensitive analysis, severely hampers its application in reliable medical testing for the early detection of cancer. Herein, we overcame these limitations by integrating an ICTS with quantum dot nanobeads (QD nanobeads), which were fabricated by encapsulating QDs within modified poly(tert-butyl acrylate-co-ethyl acrylate-co-methacrylic acid) and served as a robust signal-generating reagent for the ICTS. Prostate specific antigen (PSA) was used as a model analyte to demonstrate the performance of the QD nanobeads-based ICTS platform. Under optimized conditions, the concentration of PSA could be determined within 15 min with high sensitivity and specificity using only 40 μL of sample. The detection limit was enhanced by ∼12-fold compared with that of an ICTS that used QDs encapsulated by commercial 11-mercaptoundecanoic acid (QDs@MUA) as the signal-generating reagent. At the same time, the possible clinical utility of this approach was demonstrated by measurements recorded from PSA-positive patient specimens. Our data suggest that the QD nanobeads-based ICTS platform is not only rapid and low-cost but also highly sensitive and specific for use in quantitative point-of-care diagnostics; thus, it holds promise for becoming a part of routine medical testing for the early cancer of detection.Keywords: early cancer detection; immunochromatography test strip; prostate specific antigen (PSA); quantitative detection; quantum dot nanobeads;

Quantum dot (QD) barcodes are becoming an urgent requirement for researchers and clinicians to obtain high-density information in multiplexed suspension (bead-based) assay. However, how to improve the stability of quantum dot barcodes is a longstanding issue. Here, we present a new self-healing encapsulation strategy to generate functionalized uniform quantum dots barcodes with high physical and chemical stability. This efficient and facile strategy could make porous polymer microspheres self-heal to encapsulate QDs via the thermal motion and interaction of the molecular chains. Consequently, the new strategy solved especially the QDs leakage problem and improved the chemical stability under different pH physiological conditions as well as the longtime storage stability. In the meantime, the encoding capacity and the spatial distribution uniformity of quantum dots could be also improved. Furthermore, immunofluorescence assays for alpha fetoprotein (AFP) detections indicated that carboxyl groups on the surface of QD-encoded microspheres could facilitate efficient attachment of biomacromolecules.Keywords: AFP detections; functionalization; high stability; quantum dot barcodes; self-healing encapsulation;

Magnetic and fluorescent bifunctional nanocomposites have great potential in biomolecule detection and biological imaging applications. So far, it remains a challenge to prepare bifunctional nanocomposites with high colloidal and fluorescent stability. To address this problem, we utilized a simple ring-opening reaction to conjugate Fe3O4 and CdZnSeS quantum dots (QDs). The surface amine groups of SiO2-coated Fe3O4 nanoparticles (Fe3O4@SiO2) opened the rings of the surface maleic anhydride groups of poly(styrene-co-maleic anhydride)-coated CdZnSeS QDs (QDs@PSMA), and then the resulting nanocomposite was functionalized with Jeffamine M-1000 polyetheramine (JMP) by a ring-opening reaction. The structures and properties of the bifunctional nanocomposites were fully characterized by transmission electron microscopy, dynamic light scattering, spectrofluorometry and vibrating sample magnetometry. The results indicated that the nanocomposites prepared by the conjugation method had dramatically higher quantum yields (QYs) than those prepared by the SiO2 co-encapsulation method. After introducing JMP, the nanocomposites exhibited high fluorescent and colloidal stability over a wide pH range (pH 2–13), a low level of protein adsorption in PBS with 10% fetal bovine serum at 37 °C, and a negligible level of nonspecific binding when incubated with HeLa cells. Sandwich fluoroimmunoassay results indicated that the nanocomposites can be successfully applied in a variety of diagnosis and bioimaging applications.

For the application of biological quantitative probes, how to ameliorate chemical sensitivity and instability of quantum dots (QDs) under different environments is a longstanding issue. Here, silica and poly(EGDMA-co-MAA) as inert materials, ultrastable QD/SiO2/poly(EGDMA-co-MAA) fluorescent nanoprobes with a tri-layer core–shell structure were successfully prepared by distillation precipitation polymerization. The QD/SiO2/poly(EGDMA-co-MAA) demonstrated ultra-high chemical stability due to the synergistic combination of silica and cross-linked polymer stabilizing the fluorescence intensity of QDs under harsh chemical environments, including strong acidic solutions, which is unavailable for any of the current encapsulation technologies used alone. Immunochromatography test strips (ICTS) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using QD/SiO2/poly(EGDMA-co-MAA) as fluorescent nanoprobes. The results showed admirable reliability and sensitivity in antigen detection. What's more, reliable quantitative detection based on QD/SiO2/poly(EGDMA-co-MAA) was realized. We expect the ultrastable QDs will open up exciting opportunities in accurate quantitative analysis and imaging.

We demonstrate the facile preparation of highly luminescent Cd1−xZnxSe1−ySy quantum dot (QD)-encoded poly(styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) in a straightforward and reproducible manner. The monodisperse mesoporous PSEMBs are first swelled in chloroform. Afterwards, the reaction precursors, composed of Cd, Zn, Se and S, are impregnated into the microspheres. Subsequently, the Cd1−xZnxSe1−ySy QDs are synthesized directly within the polymer beads by thermal decomposition. The results show that a wide range of emission wavelengths (490 nm–606 nm) with a narrow full width at half maximum (FWHM) (<40 nm) is obtained by changing the ratios of the precursors. Confocal microscopy images illustrate that highly uniform, bright fluorescent beads are obtained and the QDs have infiltrated into the entire microsphere. The resulting QD barcodes exhibit remarkable stability against solvent induced QD leaching and chemical induced fluorescence quenching. The QD-encoded PSEMBs are found to be photostable in phosphate buffered saline (PBS) (pH 7.4) for at least 3 weeks. Immunoassay performances for human IgG detection indicate that the QD barcodes can be successfully applied to high-throughput multiplexed biomolecular assays.

In this paper, a biocompatible poly(γ-glutamic acid) (PGA)-based polymer with numerous thiol groups grafted onto the backbone was self-synthesized. It has been successfully used to prepare water-soluble quantum dots (QDs) with high luminescence and high stability. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, spectrofluoro-photometry, fluorescence microscopy and flow cytometer were used to characterize QDs@poly(γ-glutamic acid)-grafted cysteamine (PGA-g-MEA). The results indicated that QDs@PGA-g-MEA with an identical small size were highly luminescent with a well maintained, even increased, photoluminescence (PL) intensity when compared with the tributylphosphine oxide (TOPO) coated QDs. Meanwhile, they were highly stable in aqueous solution under a wide range of pH from 2 to 12, as well as under different temperatures. The QDs@PGA-g-MEA were then applied as fluorescent probes to detect human IgGs and the results demonstrated that QDs@PGA-g-MEA had great potential for application in immunofluorescence.

An efficient modified method combining conventional swelling method with high-temperature swelling method was applied to prepare high-stable multifunctional MNPs-QD-encoded polystyrene beads simultaneously with large encoding capacity and fast separation. In this paper, the results demonstrate that encapsulating QDs into pre-prepared MNPs-beads is the best sequence, which keeps high brightness and fast separation. The MNPs-QD-encoded microcarriers designed by our proposed method exhibit excellent performance for magnetic manipulation and optical encoding. What is more, they also have better physical and chemical stabilities. Compared with beads prepared via conventional swelling method, the leakage of nanoparticles from the designed MNPs-QD-encoded poly (styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) induced by organic solvents (e.g.cyclohexane) is less than 6%; meanwhile, fluorescence intensity of MNPs-QDs-encoded PSEMBs fluctuates slightly more in a wide range of pH 2–12 buffers. In addition, immunoassay performance for human IgG detections indicates that carboxyl groups on fluorescent microsphere surface facilitate efficient attachment of biomolecule and therefore they can be further applied to fast separation and multiplexed biomolecular assays.

Fluorescence-encoded polymer bead-based suspension arrays are widely used in biomolecular screening and diagnostic applications. The interior structure of polymer beads, especially the pore size, plays an important role in the preparation of fluorescent beads with a large encoding capacity and stability. Here, highly cross-linked carboxylated poly(styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) with optimum pore sizes were designed, fabricated, and further employed in the preparation of high-performance QD-encoded microbeads via a gradual solvent evaporation method. The PSEMBs and QD-encoded PSEMBs were characterized by scanning electron microscopy (SEM), laser scanning confocal microscopy, and spectrofluorometry. The SEM images and flow cytometry results of PSEMBs demonstrate the good sphericity and uniform particle size distribution. Confocal microscope images illustrate that highly uniform, bright fluorescent beads are obtained and the quantum dots (QDs) have filtrated into the entire microspheres, with the required pore size achieved by adjusting the content of porogen. Furthermore, QD-encoded PSEMBs were found to be photostable without leakage of QDs, and to retain their bright fluorescence for at least 20 days. Immunoassay performances for human IgG detections indicate that carboxyl groups on the fluorescent microsphere surface facilitate efficient attachment of biomacromolecules, and therefore enable high detection sensitivity (0.01 ng mL−1) in sandwich immunoreactions. These results indicate that designed optical encoding microcarriers can be successfully applied to high-throughput and multiplexed biomolecular assays. Moreover, the new porous PSEMBs designed and fabricated in this report can efficiently load other nanoparticles (e.g. magnetic nanoparticles, Au and Ag nanoparticles) for a wide range of applications.

The purpose of this study was to use polymeric liposomes (PLs) with a targeting ligand (folate) to coat superparamagnetic iron oxide nanoparticles (SPIONs) and transfer the magnetic nanoparticles from organic phases to aqueous solutions, and further evaluate their efficacy as a magnetic resonance imaging (MRI) contrast agent. The formed nanoparticles exhibited a narrow range of size dispersity (core size of the particles is about 8−10 nm) and relatively high T2 relaxivities (r2 = 164.14 s−1 mM−1 for folate-PLs-coated SPIONs). The in vitro tumor cell targeting efficacy of the folate functionalized and PLs-coated SPIONs was evaluated upon observing cellular uptake of magnetite liposomes by HeLa cells, which overexpresses surface receptors for folic acid. In the Prussian blue staining experiments, cells incubated with folate-PLs-coated SPIONs showed much higher intracellular iron density than did the cells incubated with the folate-free PLs-coated SPIONs. Meanwhile, the MTT assay explains the negligible cell cytotoxicity of SPIONs and folate-PLs-coated SPIONs. In HeLa cells, the in vitro MRI study also indicates the better T2-weighted images in folate-PLs-coated SPIONs than in folate-free PLs-coated SPIONs.

To clarify the size distribution relationship between the final fabricated beads and the initial seed particles, a theoretically investigation according to the principle of the ideal monomer absorption process was employed. Monodisperse micron-sized polystyrene beads were produced by seeded polymerization, and the size-growth process was experimentally measured. In the meanwhile, the diameter and coefficient variation rates of the final fabricated beads to the initial seed particles were also investigated. Compared the measured size distribution with the estimated, it was found that the coefficient variation was enlarged due to the inhomogeneous parameters, such as larger size distribution of seed particles, higher temperature rise rate and shorter swelling time of monomer. Therefore, the more homogeneous beads can be generated by selection of more uniform initial seed particles and meticulous adjusting synthesis parameters. Moreover, this facile and robust estimation method can be potentially employed in the analysis of other polymerization methods of dispersion polymerization and emulsion polymerization, and among others.A theoretical and experimental investigation shows that the more homogeneous final polymer beads can be obtained by employment of more uniform initial seed particles and meticulous adjusting reaction parameters.

We are reporting a simple and rapid method to prepare superparamagnetic, controlled size, and monodispersed magnetic cationic polymeric liposomes (MCPL) by octadecyl quaternized carboxymethyl chitosan (OQCMC) and cholesterol. The whole process is only about 25 min with simple thin-film dispersion and solvent evaporation method. Hydrophilic magnetic nanoparticles (LM) and hydrophobic magnetic nanoparticles (BM) can be encapsulated into these cationic polymeric liposomes, simultaneously or respectively. A model hydrophobic drug indomethacin can be successfully filled in MCPL with high drug loading capacity 22%. MCPL encapsulating BM also showed strong DNA (pEGFP) binding ability. Drug-loaded MCPL have a long and controlled sustained release profile by changing the number of polymeric lipid layer. These functional MCPL nanospheres can be allowed to serve as ideal candidates for many biomedical applications.

Folic acid and TAT peptide were conjugated on the octadecyl-quaternized, lysine-modified chitosan-cholesterol polymeric liposomes (FA-TATp-PLs) to investigate their potential feasibility for tumor-targeted drug delivery.FA-TATp-PLs encapsulating paclitaxel or calcein were synthesized and characterized. Cellular uptake of PLs, FA-PLs, TATp-PLs and FA-TATp-PLs was studied by confocal laser scanning microscopy (CLSM) in folate receptor (FR)-positive KB nasopharyngeal epidermal carcinoma cells and FR-deficient A549 lung cancer cells. In vitro and in vivo antitumor activity of paclitaxel-loaded FA-TATp-PLs were also evaluated in KB and A549 cells as well as in a murine KB xenograft model.Our data showed that 80% paclitaxel released from FA-TATp-PLs in 2 weeks. Different from other various PLs, CLSM analyses showed that FA-TATp-PLs had a significantly high efficient intracellular uptake in both KB and A549 cells. These data revealed the targeting effects of folate decoration, the transmembrane ability of TAT peptide as well as a synergistic interaction between them. In addition, paclitaxel-loaded FA-TATp-PLs exhibited a more superior antitumor effect in vitro and in vivo as compared to that with Taxol®.FA-TATp-PLs possessing both targeting effect and transmembrane ability may serve as a promising carrier for the intracellular delivery of therapeutic agents.

The apparent density, an intrinsic physical property of polymer beads, plays an important role in the application of beads in micro-total analysis systems and separation. Here we have developed a new, facile and milligram-scale method to describe the motion of beads in aqueous solution and further detect the apparent density of beads. The motion of beads in solutions is determined by the viscosity of solutions and the density difference between beads and solutions. In this study, using various glycerol aqueous solutions with certain viscosities and densities, the motion time (i.e. floating or sedimentation time) of hybrid polymer beads was experimentally measured and theoretically deduced, and consequently, the apparent density of monodisperse beads can be quickly and easily calculated. The results indicated that the present method provided a more precise way to predict the movement of hybrid beads in aqueous solution compared with the approach for commercial use. This new method can be potentially employed in flow cytometry, suspension stability, and particle analysis systems.

Highly cross-linked polystyrene beads of 9.2 μm were synthesized by seed polymerization with styrene as monomer and divinylbenzene as cross linker. Other sized monodisperse PS microspheres were also prepared by varying seed particle diameter and proportion of swelling agents. Furthermore, the polystyrene beads were stained by gradual solvent evaporation method using dyes such as rhodamine 101 and acridine orange. Gradual solvent evaporation method facilitates a high concentration of fluorescent dyes on beads. This is the key to obtain fluorescent beads with high intensity. The results showed that the fabricated fluorescent microspheres could be excited to various wavelengths (such as yellow, green, red and scarlet). Our synthesized microspheres offer high fluorescence emission efficiency compared to commercial fluorescent microspheres in the mean time have other properties in common.

Recently, it has been proved that quantum dots (QDs) hold the potential to be used in the bioanalysis as fluorescent probes for their many unique optical properties. In this paper, immunofluorescence assay, an integration of particle-based immunoassays and fluorescent QD-probes, was constructed. Firstly, high quality CdSe/ZnS QDs were prepared. Then after being water-solubilized by amphiphilic polymer based on self-assembling, the QDs were labeled by immunoglobulin G (IgG) antibody. At the same time, both carboxyl-polystyrene (PS) and magnetic carboxyl-PS microspheres were prepared and coated by antigens. The antigen sensitized PS microspheres were specifically captured by the QD–IgG bioconjugates based on the antibody-antigen reaction, which was confirmed by the immunofluorescence test in vitro. The sensitivity of current assay was tested by sandwich immunofluorescence assay using human alpha fetoprotein (AFP) as antigen model. The detection limit of AFP antigen is 4.9 ng/mL.

We developed a novel method to prepare multi-colors high fluorescent/superparamagnetic nanoparticles (FMNPs) employing hydrophobic multi-color quantum dots (QDs) and hydrophobic Fe3O4 (MNPs) via ultrasonic emulsification method. This structural procedure was simple, one-off, and timesaving. Different-sizes FMNPs with encoding single/multi-color QDs and MNPs were achieved. Analysis with transmission electron microscopy (TEM) and particle size analyzer demonstrated that the as-prepared samples were spherical, uniform in size distribution; Ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) measurement showed the FMNPs had good optical properties, lacking of fluorescence resonance energy transfer (FRET) inside FMNPs; vibrating sample magnetometer (VSM) indicated that FMNPs were superparamagnetic. These results indicate that the as-prepared FMNPs have potential of serving as a hybrid of QDs and MNPs in bioanalysis communities.A novel method to prepare multi-color high fluorescent/superparamagnetic nanoparticles (FMNPs) employing hydrophobic multi-color quantum dots (QDs) and hydrophobic Fe3O4 (MNPs) via ultrasonic emulsification method.

Micron-sized, monodisperse, superparamagnetic, luminescent composite poly(glycidyl methacrylate) (PGMA) microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows: preparation of monodisperse poly(glycidyl methacrylate) microspheres by dispersion polymerization method; modification of poly(glycidyl methacrylate) microspheres with ethylene diamine to form amino-groups; impregnation of iron ions (Fe2+ and Fe3+) inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite (Fe3O4) nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots (QDs) into magnetic polymer microspheres. Scanning electron microscopy (SEM) was used to characterize surface morphology and size distribution of composite microspheres. The average size of microspheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multifunctional composite microspheres are promising to be used in a variety of bioanalytical assays involving luminescence detection and magnetic separation.

In this study the w/o/w extraction-evaporation technique was adopted to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres loading recombinant human epidermal growth factor (rhEGF). The microspheres were characterized for morphology by transmission electron microscopy (TEM) and particle size distribution. The release performances, the proliferation effects and therapeutic effects of rhEGF-loaded PLGA microspheres were all studied. The results showed that these spherical microspheres had a narrow size distribution and a high drug encapsulation efficiency (85.6%). RhEGF-loaded microspheres enhanced the growth rate of fibroblasts and wound healing more efficiently than pure rhEGF. The number of the proliferating cell nuclear antigen (PCNA) in the epidermis layer with the microsphere treatment was significantly larger than those of the control groups. Overall locally sustained delivery of rhEGF from biodegradable PLGA microspheres may serve as a novel therapeutic strategy for diabetic ulcer repair.

We developed a novel method to water-solubilize hydrophobic quantum dots (QDs) in water via ultrasonic emulsification method. This structural procedure was simple and one-step. Analysis with transmission electron microscopy (TEM), ultraviolet–visible (UV–vis) absorption spectroscopy, X-ray powder diffraction (XRD), photoluminescence (PL) measurement, and fluorescence microscopy demonstrated that the as-prepared samples were uniform in size distribution with ca. 40 nm, and had good optical properties. QDs were conjugated with antibodies. Then, gel filtration chromatography was used to separate QD–antibody bioconjugates. Antibodies were fluorescently labelled with polymer-coated QDs nanoparticles via the conjugation procedure and their immunoassay activity confirmed covalent conjugation. These results indicate that QDs can serve as substitutes for traditional organic dyes in the field of biodetection.

The design and construction of effective delivery vectors for drugs is very important. We have discovered that octadecyl quaternized carboxymethyl chitosan (OQCMC) in combination with cholesterol (Chol) could form stable vesicles with structure similar to that of conventional liposomes prepared from phosphatidylcholine/cholesterol (PC/Chol). Compared to conventional liposomes, our polymeric liposomes formed by OQCMC/Chol have many excellent features, such as good physical and thermal stability, excellent solubility in water, and high effectiveness in drug encapsulation. Trans-activating transcriptional activator protein (TAT peptide) could be connected on the surface of cationic polymeric liposomes by using cross-linking reagent N-hydroxysuccinimidyl-3-(2-pyridyldithio) propionate (SPDP). Also, oil-soluble magnetic nanoparticles were used to verify the bilayer structure of the polymeric liposomes and their ability to solublize hydrophobic materials. Using different preparation methods, OQCMC/Chol could easily be made into nanoscale particles by encapsulating both hydrophilic and hydrophobic components. We have successfully prepared polymeric liposomes encapsulating quantum dots (QDs), superparamagnetic nanoparticles, or both. Vincristine was also encapsulated in the polymeric liposomes with high drug encapsulation efficiency (90.1%). Vincristine-loaded magnetic polymeric liposomes were stable in aqueous solution and exhibited slow, steady release action over 2 weeks under physiologic pH (7.4). This allows the use of multifunctional cationic polymeric liposomes, such as those developed here from modified chitosan, in various applications such as cancer diagnosis and treatment.

Mucus is a viscoelastic and adhesive obstacle which protects vaginas, eyes and other mucosal surfaces against foreign pathogens. Numerous diseases that affect the mucosa could be afforded prophylactic and therapeutic treatments with fewer systemic side effects if drugs and genes could be sufficiently delivered to the target mucosal tissues. But drugs and genes are trapped effectively like other pathogens and rapidly removed by mucus clearance mechanism. The emergence of micro- and nano-delivery technologies combined with the realization of non-invasive and painless administration routes brings new hope for the treatment of disease. For retained drugs and genes to mucosal tissues, carriers must increase retention time in the mucus to make full contact with epithelial cells and be transported to target tissues. This review focuses on the current development of micro- and nano-carriers to improve the localized therapeutic efficiency of targeted and sustained drug and gene delivery in mucosal tissues.

•The Dox-loaded UCN@mSiO2-(Azo + RB) nanoimpellers were prepared for synergistic therapy.•(NaYF4:Yb, Tm)@0.6(NaYF4: Yb, Er) UCNs were used in the nanoimpellers.•Azobenzene groups conjugation provided a powerful tool for the controlled release of drugs.How to encapsulate and transport the payload of multiple therapeutic compounds avoiding premature leakage, and simultaneously co-release them rapidly at specific lesions still remains the major concern in clinic. Herein, we designed the UCN@mSiO2-(Azo + RB) (azobenzene groups and Rose Bengal) nanoimpellers, which used the multicolor-emission capability of the core-shell upconverting nanoparticles (UCNs) at a single excitation wavelength to co-release anticarcinogen doxorubicin (Dox) and reactive oxygen species (ROS) for combined chemotherapy and photodynamic therapy (PDT). The nanoimpeller was formed from UCN inner core, mesoporous silica shell, and light triggers Azo and RB molecules. The UCNs emitting UV/blue and green/red multiband light were used to activate the photoresponsive Azo and photosensitizer RB molecules; The mesoporous silica shell offered the possibilities to load anticancer drug and conjugate the light triggers; As there are strong charge interaction and hydrogen bonds between Dox and surface silanols of mesoporous silica, the azobenzene molecules worked as “gatekeeper” and “molecular stirrer” to precisely trap and propel the release of Dox under the external stimuli. The time-dependent drug release analysis, ROS production test and PDT test suggested that the nanoparticles may serve as a useful multifunctional nanoplatform for synergistic therapy and cancer diagnostic.

Enhanced tumor cellular internalization and triggered drug release are two main concerns in the development of nanoparticles for antitumor drug delivery. In this article, a new kind of smart pH- and reduction-dual-responsive drug- loaded PEG coated polymeric lipid vesicle (PPLV) that can achieve both enhanced tumor cellular internalization and triggered drug release has been designed and prepared. The PPLVs were formed from amphiphilic dextran derivatives. The antitumor drug, doxorubicin (DOX), was loaded in the cores of the PPLVs. The newly developed PPLVs had a nanosized structure (∼40 nm) with PEG coating, so they were neutral and had high colloidal stability in the blood circulation. The in vitro physicochemical characterizations showed that the PPLVs lose their PEG coating and expose the positive surface charge under acidic environments. The in vitro cellular uptake study indicated that the acidic-treated PPLVs can efficiently enter tumor cells. It has been demonstrated by in vitro DOX release profiles that the PPLVs can achieve a triggered drug release in response to the reduction environment. The MTT assay demonstrated that DOX-loaded PPLVs treated with pH 5.0 solution had higher antitumor activity than DOX-loaded PPLVs treated with pH 7.4 solution. These results suggested that the PPLVs were promising nanoparticles for smart antitumor drug delivery applications.

Currently, protein/peptide-based biomimetic mineralization has been demonstrated to be an efficient and promising strategy for synthesis of inorganic/metal nanoparticles (NPs) for bioapplications. This strategy is found to be bio-inspired, straightforward, and environmentally benign. It can produce inorganic/metal NPs with good stability, excellent biocompatibility, high water solubility, and rich surface functional groups for further bioconjunction. In this review, we provide a summary of the previously reported proteins/peptides as biotemplates involved in biomimetic mineralization synthesis, and categorize the obtained inorganic NPs ranging from metal nanoclusters (MNCs), quantum dots (QDs), gadolinium derivatives, and metal sulfide nanoparticles (MSNPs) with an emphasis on the recent progress in their use in biomedical applications, including bio-sensing, ion detection, bio-labeling, in vivo imaging and therapy. In the end, the challenges and future outlook in this emerging area are also discussed.

Sensitive and specific fluorescence imaging-guided photothermal therapy (PTT) with high-efficiency is of essential importance and is still a challenge for nanotheranostics. To address these issues, we developed activatable ultrasmall gold nanorods (AUGNRs) to realize “off–on” switched fluorescence imaging-guided efficient PTT. Herein, the GNRs with an ultrasmall small size (∼4 nm) were set as the PTT platform due to their distinct absorption-dominant characteristics, generating an enhanced photothermal conversion efficiency. A near infrared (NIR) dye, Cy5, was conjugated to the surface of the ultrasmall GNRs for fluorescence imaging. Due to the strong localized surface plasmon resonance (LSPR), the fluorescence of Cy5 could be remarkably quenched by the GNRs and show an “off” state under normal conditions. As the AUGNRs are internalized by tumor cells, their ability of fluorescence imaging would be activated by glutathione (GSH) for the reducing action of GSH. Given the higher intracellular GSH concentration in tumor cells, a highly selective intracellular fluorescence imaging pattern was provided by the AUGNRs. As a result, the obtained AUGNRs revealed a uniformly rod-like structure with an aspect ratio of ∼4 and showed an enhanced photothermal conversion efficiency. The in vitro cellular uptake study indicated that the AUGNRs can efficiently enter the tumor cells. It has been demonstrated by in vitro Cy5 release profiles that the AUGNRs could achieve a triggered Cy5 release in response to GSH. The MTT assay and calcein AM/PI co-staining demonstrated that the cancer cells could be effectively killed when exposed to a NIR laser. Our work presents great potential for activated fluorescence imaging-guided PTT with high specificity and efficiency, as a promising method for future clinical cancer diagnostics and treatment.

Various nanoparticles have been employed for gene delivery. Revealing the endocytosis or phagocytosis behaviors of the gene delivery system is critical for designing sophisticated gene therapies. Herein, a kind of water-soluble PEI capped AgInS/ZnS (ZAIS@PEI) quantum dot was synthesized as a self-indicating gene vector in the presence of branched polyethylenimine (PEI) and mercaptopropionic acid (MPA). The as-prepared ZAIS@PEI QDs could efficiently condense plasmid DNA into nanocomplexes with strong fluorescence, which can reveal their positions during gene transfection. Our results confirmed that ZAIS@PEI could mediate plasmid DNA delivery into HeLa cells with the high transfection efficiency of 40% and low cytotoxicity, meanwhile allowing the real-time monitoring of gene transfection. The obtained ZAIS@PEI QDs were verified as versatile self-tracking gene vectors, which integrated gene delivery with bioimaging functions without external labeling.

An efficient modified method combining conventional swelling method with high-temperature swelling method was applied to prepare high-stable multifunctional MNPs-QD-encoded polystyrene beads simultaneously with large encoding capacity and fast separation. In this paper, the results demonstrate that encapsulating QDs into pre-prepared MNPs-beads is the best sequence, which keeps high brightness and fast separation. The MNPs-QD-encoded microcarriers designed by our proposed method exhibit excellent performance for magnetic manipulation and optical encoding. What is more, they also have better physical and chemical stabilities. Compared with beads prepared via conventional swelling method, the leakage of nanoparticles from the designed MNPs-QD-encoded poly (styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) induced by organic solvents (e.g.cyclohexane) is less than 6%; meanwhile, fluorescence intensity of MNPs-QDs-encoded PSEMBs fluctuates slightly more in a wide range of pH 2–12 buffers. In addition, immunoassay performance for human IgG detections indicates that carboxyl groups on fluorescent microsphere surface facilitate efficient attachment of biomolecule and therefore they can be further applied to fast separation and multiplexed biomolecular assays.

Fluorescence-encoded polymer bead-based suspension arrays are widely used in biomolecular screening and diagnostic applications. The interior structure of polymer beads, especially the pore size, plays an important role in the preparation of fluorescent beads with a large encoding capacity and stability. Here, highly cross-linked carboxylated poly(styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) with optimum pore sizes were designed, fabricated, and further employed in the preparation of high-performance QD-encoded microbeads via a gradual solvent evaporation method. The PSEMBs and QD-encoded PSEMBs were characterized by scanning electron microscopy (SEM), laser scanning confocal microscopy, and spectrofluorometry. The SEM images and flow cytometry results of PSEMBs demonstrate the good sphericity and uniform particle size distribution. Confocal microscope images illustrate that highly uniform, bright fluorescent beads are obtained and the quantum dots (QDs) have filtrated into the entire microspheres, with the required pore size achieved by adjusting the content of porogen. Furthermore, QD-encoded PSEMBs were found to be photostable without leakage of QDs, and to retain their bright fluorescence for at least 20 days. Immunoassay performances for human IgG detections indicate that carboxyl groups on the fluorescent microsphere surface facilitate efficient attachment of biomacromolecules, and therefore enable high detection sensitivity (0.01 ng mL−1) in sandwich immunoreactions. These results indicate that designed optical encoding microcarriers can be successfully applied to high-throughput and multiplexed biomolecular assays. Moreover, the new porous PSEMBs designed and fabricated in this report can efficiently load other nanoparticles (e.g. magnetic nanoparticles, Au and Ag nanoparticles) for a wide range of applications.

Fluorescent signal-based lateral flow immunochromatographic strips (FLFICS) have received great expectations since they effectively improve detection sensitivity with quantitative analysis, and still retain the advantages of simplicity, rapidness, and portability of a common lateral flow immunochromatographic strip (LFICS). Diverse fluorescent reporters have promoted development of FLFICS, such as fluorescent dyes, quantum dots (QDs), an up-converting phosphor (UCP), lanthanide labels, and other fluorescence nanoparticles. In this work, we discuss the different fluorescent reporters applied with LFICS and their unique properties as well as signal amplification strategies helping to enhance detection performance. Benefitting from these sensitive and accurate fluorescent labels, FLFICS commendably satisfies requirements for detecting different disease biomarkers in medical diagnosis, strict supervision of food safety, and water pollution. This work also gives a short introduction to trends in the development of future FLFICS technology.

In this paper, a biocompatible poly(γ-glutamic acid) (PGA)-based polymer with numerous thiol groups grafted onto the backbone was self-synthesized. It has been successfully used to prepare water-soluble quantum dots (QDs) with high luminescence and high stability. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, spectrofluoro-photometry, fluorescence microscopy and flow cytometer were used to characterize QDs@poly(γ-glutamic acid)-grafted cysteamine (PGA-g-MEA). The results indicated that QDs@PGA-g-MEA with an identical small size were highly luminescent with a well maintained, even increased, photoluminescence (PL) intensity when compared with the tributylphosphine oxide (TOPO) coated QDs. Meanwhile, they were highly stable in aqueous solution under a wide range of pH from 2 to 12, as well as under different temperatures. The QDs@PGA-g-MEA were then applied as fluorescent probes to detect human IgGs and the results demonstrated that QDs@PGA-g-MEA had great potential for application in immunofluorescence.

We demonstrate the facile preparation of highly luminescent Cd1−xZnxSe1−ySy quantum dot (QD)-encoded poly(styrene-co-ethylene glycol dimethacrylate-co-methacrylic acid) beads (PSEMBs) in a straightforward and reproducible manner. The monodisperse mesoporous PSEMBs are first swelled in chloroform. Afterwards, the reaction precursors, composed of Cd, Zn, Se and S, are impregnated into the microspheres. Subsequently, the Cd1−xZnxSe1−ySy QDs are synthesized directly within the polymer beads by thermal decomposition. The results show that a wide range of emission wavelengths (490 nm–606 nm) with a narrow full width at half maximum (FWHM) (<40 nm) is obtained by changing the ratios of the precursors. Confocal microscopy images illustrate that highly uniform, bright fluorescent beads are obtained and the QDs have infiltrated into the entire microsphere. The resulting QD barcodes exhibit remarkable stability against solvent induced QD leaching and chemical induced fluorescence quenching. The QD-encoded PSEMBs are found to be photostable in phosphate buffered saline (PBS) (pH 7.4) for at least 3 weeks. Immunoassay performances for human IgG detection indicate that the QD barcodes can be successfully applied to high-throughput multiplexed biomolecular assays.

Magnetic and fluorescent bifunctional nanocomposites have great potential in biomolecule detection and biological imaging applications. So far, it remains a challenge to prepare bifunctional nanocomposites with high colloidal and fluorescent stability. To address this problem, we utilized a simple ring-opening reaction to conjugate Fe3O4 and CdZnSeS quantum dots (QDs). The surface amine groups of SiO2-coated Fe3O4 nanoparticles (Fe3O4@SiO2) opened the rings of the surface maleic anhydride groups of poly(styrene-co-maleic anhydride)-coated CdZnSeS QDs (QDs@PSMA), and then the resulting nanocomposite was functionalized with Jeffamine M-1000 polyetheramine (JMP) by a ring-opening reaction. The structures and properties of the bifunctional nanocomposites were fully characterized by transmission electron microscopy, dynamic light scattering, spectrofluorometry and vibrating sample magnetometry. The results indicated that the nanocomposites prepared by the conjugation method had dramatically higher quantum yields (QYs) than those prepared by the SiO2 co-encapsulation method. After introducing JMP, the nanocomposites exhibited high fluorescent and colloidal stability over a wide pH range (pH 2–13), a low level of protein adsorption in PBS with 10% fetal bovine serum at 37 °C, and a negligible level of nonspecific binding when incubated with HeLa cells. Sandwich fluoroimmunoassay results indicated that the nanocomposites can be successfully applied in a variety of diagnosis and bioimaging applications.

For the application of biological quantitative probes, how to ameliorate chemical sensitivity and instability of quantum dots (QDs) under different environments is a longstanding issue. Here, silica and poly(EGDMA-co-MAA) as inert materials, ultrastable QD/SiO2/poly(EGDMA-co-MAA) fluorescent nanoprobes with a tri-layer core–shell structure were successfully prepared by distillation precipitation polymerization. The QD/SiO2/poly(EGDMA-co-MAA) demonstrated ultra-high chemical stability due to the synergistic combination of silica and cross-linked polymer stabilizing the fluorescence intensity of QDs under harsh chemical environments, including strong acidic solutions, which is unavailable for any of the current encapsulation technologies used alone. Immunochromatography test strips (ICTS) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using QD/SiO2/poly(EGDMA-co-MAA) as fluorescent nanoprobes. The results showed admirable reliability and sensitivity in antigen detection. What's more, reliable quantitative detection based on QD/SiO2/poly(EGDMA-co-MAA) was realized. We expect the ultrastable QDs will open up exciting opportunities in accurate quantitative analysis and imaging.

Conventional liposomes (CLs) have been used as a transdermal drug delivery system for enhancing the delivery of hydrophilic drugs into/through the skin. However, their applications have been constrained by their limited penetration ability and poor stability. In this article, a new kind of transactivating transcriptional activator peptide (TAT)-conjugated polymeric lipid vesicles (TPLVs) formed from amphiphilic lysine–linoleic acid modified dextran (LLD) and cholesterol (Chol) has been prepared successfully. The newly developed TPLVs had a bilayer structure similar to CLs. The TPLVs also have smaller particle size, narrower distribution, higher positive charge and much better stability than the CLs; they remained stable in aqueous solutions for up to 60 days without aggregation. The in vitro and in vivo skin permeation studies revealed that TPLVs delivered a higher amount of drug through the skin than CLs, indicating enhanced drug transdermal activities. The synergetic effects of abovementioned features and the cell-penetrating peptide TAT might have contributed to the improved skin penetration ability of the TPLVs. Similar to CLs, TPLVs began to show limited cytotoxicity against human umbilical vein endothelial cells at a concentration of 200 μg mL−1. The in vitro release profiles showed that the TPLVs achieved a sustained release of lidocaine. These results suggest that the TPLVs may be utilized as an efficient carrier to replace CLs for transdermal drug delivery.

In clinics, the application of photodynamic therapy (PDT) in deep tissue is severely constrained by the limited penetration depth of visible light that was used for activating the photosensitizer (PS). In this work, a protocol of a UCN@SiO2@crosslinked lipid triple layer nanoparticle was developed successfully. The triple layer nanoparticle was assembled from the hydrophobic upconverting nanoparticle (UCN) core, the mesoporous silica middle shell and the cross-linked lipid out shell. The photosensitizer zinc phthalocyanine (ZnPc) loaded triple layer nanoparticle offers possibilities to solve the problem mentioned above. The UCN core works as a transducer to convert deeply penetrating near infrared light to visible light for activating ZnPc for photo dynamic therapy. The middle shell is used for loading ZnPc and the out shell can prevent the drug leaking effectively. The experiment results showed that with the help of the cross-linked lipid shell, the triple layer nanoparticle could prevent the drug leaking and particle aggregation. The ROS production test and PDT test suggested that the fluorescence emitted from the UCNs excited by NIR can effectively activate the photosensitizer ZnPc to generate cytotoxic ROS. The UCN@SiO2@crosslinked lipid triple layer nanoparticle modified with RGD has a much better treatment effect in cancer cells. Our data suggest that the UCN@SiO2@crosslinked lipid triple layer nanoparticle may be a useful nanoplatform for future PDT treatment in deep cancer therapy based on the upconverting mechanism.

A smart pH-responsive photodynamic therapy system based on upconversion nanoparticle loaded PEG coated polymeric lipid vesicles (RB-UPPLVs) was designed and prepared. These RB-UPPLVs which are promising agents for deep cancer photodynamic therapy applications can achieve enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.