The complex pathogenic mechanisms of Alzheimer’s disease (AD) include the aggregation of β-amyloid peptides (Aβ) into oligomers or fibrils as well as Aβ-mediated oxidative stress, which require comprehensive treatment. Therefore, the inhibition of Aβ aggregation and free-radical scavenging are essential for the treatment of AD. Nanoparticles (NPs) have been found to influence Aβ aggregation process in vitro. Herein, we report the inhibition effects of molybdenum disulfide (MoS2) NPs on Aβ aggregation. Polyvinylpyrrolidone-functionalized MoS2 NPs were fabricated by a pulsed laser ablation method. We find that MoS2 NPs exhibit multifunctional effects on Aβ peptides: inhibiting Aβ aggregation, destabilizing Aβ fibrils, alleviating Aβ-induced oxidative stress, as well as Aβ-mediated cell toxicity. Moreover, we show that MoS2 NPs can block the formation of the Ca2+ channel induced by Aβ fibrils in the cell membrane for the first time. Thus, these observations suggest that MoS2 NPs have great potential for a multifunctional therapeutic agent against amyloid-related diseases.Keywords: amyloid peptide; antioxidant activity; MoS2 nanoparticles; neuronal cytotoxicity; pulsed laser ablation;

Due to low cost and high stability, the applications of inorganic nanomaterials as efficient alternatives to natural enzymes are drawing much attention. In this work, novel CuO/Pt nanocomposites with high peroxidase-like activity were designed and applied for the colorimetric detection of ascorbic acid (AA). The nanocomposites were prepared by decorating Pt NPs on the surface of CuO nanosheets, which displayed good uniformity and showed improved distribution and stability. The catalytic activity of the prepared CuO/Pt nanocomposites was tested against various chromogenic substrates in the presence of H2O2, which displayed efficient peroxidase-like activity and high catalytic stability against temperature. The catalytic mechanism of the CuO/Pt nanocomposites was investigated by hydroxyl radical detection. The peroxidase-like activity decreased significantly in the presence of AA. On the basis of the inhibition property, a colorimetric biosensor was constructed by using the CuO/Pt nanocomposites for the detection of AA. It showed a high selectivity against amino acids, carbohydrates and normal ions. Thus, this work provides new insights into the application of inorganic nanocomposite-based nanozymes in the biosensing field.

Bacterial infection is a worldwide health problem. Finding new potential antibacterial materials and developing advanced treatment strategies are becoming increasingly important and urgent. Herein, a versatile graphene-based photothermal nanocomposite was prepared for rapidly capturing and effectively eliminating both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and for destroying bacterial biofilms with near-infrared (NIR) irradiation. In this work, chitosan-functionalized magnetic graphene oxide (GO–IO–CS) was synthesized as a multifunctional therapy agent through a hydrothermal method. Chitosan could efficiently contact and capture bacteria by its positively charged surface functional groups, and graphene oxide could act as an effective photothermal killer to convert NIR light into local heat to enhance antibacterial activity. The super-paramagnetic properties of GO–IO–CS made it easy to separate and aggregate the bacteria, so improving the photothermal sterilization efficiency. GO–IO–CS was demonstrated to eliminate bacteria effectively after 10 min of NIR irradiation and to destroy bacterial biofilms. Furthermore, this antibiotic agent could be regenerated with an external magnet and reused in a subsequent antibacterial application.

Single or few-layered MoS2 nanosheets, as a novel class of 2D nanomaterials, have received tremendous attention due to their fantastic physical and chemical properties. Here, we fabricated MoS2–PEG–CpG with a small and uniform size as a multifunctional platform for photothermal enhanced immunotherapy. MoS2 nanosheets were fabricated by chemical exfoliation and further probe sonication. To realize MoS2-based adjuvant delivery, MoS2 nanosheets were functionalized with cytosine–phosphate–guanine (CpG) and polyethylene glycol (PEG) to form MoS2–PEG–CpG nanoconjugates. As an efficient nanocarrier with excellent near infrared-light (NIR) absorbing performance, MoS2–PEG–CpG significantly promotes CpG intracellular accumulation and the effect can be further enhanced by photothermal treatment. In addition, the enhanced uptake can stimulate the production of proinflammatory cytokines and remarkably elevate the immune response level. Finally, we found that MoS2–PEG–CpG could reduce the proliferative activity of cancer cells when co-cultured with a macrophage-like cell upon NIR irradiation, implying a novel strategy for multifunctional therapeutics against cancers.

•A graphene oxide-iron oxide (GOIO) nanocomposite is successfully fabricated.•The GOIO nanocomposite can effectively inhibit Aβ 42 peptide aggregation.•The depolymerization of Aβ 42 fibrils by the GOIO nanocomposite is also observed.Inhibiting amyloid β (Aβ) aggregation has drawn much attention because it is one of the main reasons for the cause of Alzheimer’s disease (AD). Here we have synthesized a nanocomposite of graphene oxide-iron oxide (GOIO) and demonstrated its ability of modulating Aβ aggregation. The inhibition effects of the GOIO nanocomposite on Aβ aggregates was studied by Thioflavin T fluorescence assay, circular dichroism and transmission electron microscopy, respectively. Furthermore, the cell viability study revealed that the GOIO nanocomposite can reduce the toxicity of Aβ fibrils to neuroblastoma cells. Our results demonstrated that the combination of GO and IO as a nanocomposite material has a potential use for the design new therapeutic agents for the treatment of Alzheimer’s disease.Download high-res image (156KB)Download full-size image

AbstractMoS2-based nanocomposites are emerging as novel versatile materials. Here, uniform Pt3Au1 nanoparticles (NPs) decorated few-layer MoS2 nanosheets were fabricated as novel enzyme mimics. Compared to pure MoS2 nanosheets, the as-prepared MoS2-Pt3Au1 nanocomposites displayed enhanced peroxidase-like activity. The nanocomposites also possessed well dispersibility and high stability in water. With these findings, a simple, fast and low-cost colorimetric detection of phenol with high sensitivity and selectivity is developed, which is based on oxidative coupling reaction of phenol and 4-aminoantipyine in the presence of H2O2 as an oxidant to form pink color products. This work provides a type of MoS2-NP composites as enzyme mimics for many potential applications in catalysis.

A novel magnetic-enhanced colorimetric assay was constructed based on aptamer conjugated PtCo bimetallic nanoparticles (NPs) with high oxidase-like catalytic activity, high water solubility, low cell toxicity, and superparamagnetic properties. It was found that the incorporation of magnetic metal Co atoms into NPs could not only be facilitated for magnetic separation, but also resulted in the significantly improved oxidase-like catalytic activity of the nanoparticles for cancer-cell detection without the destructive H2O2. The present work demonstrates a general strategy for the design of multifunctional materials based on bimetallic nanoparticles for different applications, such as biosensors, nanocatalysts and nanomedicine.

To extend the functionalities of two-dimensional graphene-like layered compounds as versatile materials, the modification of transition metal dichalcogenide nanosheets such as MoS2 with metal nanoparticles is of great and widespread interest. However, few studies are available on the preparation of bimetallic nanoparticles supported on MoS2. Herein, a facile and efficient method to synthesize MoS2–PtAg nanohybrids by decorating ultrathin MoS2 nanosheets with octahedral Pt74Ag26 alloy nanoparticles has been reported. The as-prepared MoS2–Pt74Ag26 nanohybrids were investigated as novel peroxidase mimics to catalyze the oxidation of classical peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue colored reaction and exhibiting typical Michaelis–Menten kinetics. MoS2–Pt74Ag26 has a higher affinity for H2O2 than horseradish peroxidase (HRP) and a higher vmax value with TMB as the substrate than MoS2. The improved catalytic activity of hybrids for colorimetric reactions could be attributed to the synergistic effects of octahedral Pt74Ag26 nanoparticles and ultrathin MoS2 nanosheets as supports. Meanwhile, the generation of active oxygen species (˙OH) by H2O2 decomposition with MoS2–Pt74Ag26 was responsible for the oxidation of TMB. On the basis of these findings, a colorimetric method based on MoS2–Pt74Ag26 nanohybrids that is highly sensitive and selective was developed for glucose detection. Lower values of the limit of detection (LOD) were obtained, which is more sensitive than MoS2 nanosheets.

Nanowires have attracted much attention due to their potential bioapplications, such as delivery of drugs or sensing devices. Here we report the development of a unique cell-capture and release platform based on nanowires. The combination of nanowires, surface-binding peptides, and cell-targeting aptamers leads to specific and efficient capture of cancer cells. Moreover, the binding processes are reversible, which is not only useful for downstream analysis but also for reusability of the substrate. Our work provides a new method in the design of the cell-capture and release platform, which may open up new opportunities of developing cell-separation and diagnosis systems based on cell-capture techniques.Keywords: aptamers; cell-capture; GaN; nanowires; peptides

Hybrid composite materials are particularly useful and offer great opportunities for catalysis due to their multifunctionalities. Taking advantage of the high catalytic properties of bimetallic alloy nanoparticles, the large specific surface area and co-catalytic function of MoS2 nanosheets, we prepare a novel MoS2/PtCu nanocomposite with intrinsic high oxidase- and peroxidase-like activity. The preparation of MoS2/PtCu nanocomposites does not require organic solvents or high temperature. The introduction of single-layer MoS2 nanosheets not only improves porous PtCu nanoparticles with a fine dispersion, but also readily incorporates recognition elements. As a mimic oxidase, the independence of hydrogen peroxide shows the good biocompatibility of MoS2/PtCu for promising bioapplications. On the basis of oxidase-like activity, a novel colorimetric aptasensor (apt-MoS2/PtCu) was developed and its application in the colorimetric detection of cancer cells with different MUC1-protein densities was demonstrated. The as-prepared apt-MoS2/PtCu shows good sensitivity and selectivity to targeting cells. The proposed strategy will facilitate the utilization of MoS2-based nanocomposites with high oxidase/peroxidase activities in biotechnology, biocatalysis etc.

The current cancer therapies in clinical practice demonstrate the need for improvements such as improving the efficiency and reducing the severe side effects. Herein, we integrated the targeted chemotherapy and photothermal therapy in a multifunctional drug-delivery platform. The targeting DNA aptamer (Apt)–modified graphene oxide–gold nanoparticle (GO–AuNP) composites were successfully synthesized. The doxorubicin (DOX)–loaded GO–AuNP–Apt system showed heat-stimulative and sustained release characteristics. In vitro cell cytotoxicity experiments showed that combined therapy had the highest rate of death of tumor cells compared to that of single photothermal therapy or chemotherapy. Furthermore, aptamer-modification could significantly enhance the accumulation of nanocomposites within cancer cells. Our study demonstrates that aptamer–modified GO–Au nanocomposites may have potential in the development of targeted photothermal therapy and chemotherapy against cancer cells.

Today cancer is one of the most life-threatening diseases in the world. The conventional cancer therapies, including surgery, chemo- and radiation therapies, have some disadvantages, such as limited efficiency and significant side effects. It is necessary to develop new therapeutic treatments. Herein, we integrated the targeted photocatalytic and chemotherapy in a multifunctional drug-delivery platform. The aptamer-functionalized ZnO nanoparticles (NPs) were successfully synthesized. The anti-cancer drug was loaded in the aptamer–ZnO NP system. In vitro cell cytotoxicity experiments showed that combined therapy had a higher rate of death of cancer cells compared to that of single photocatalytic or chemotherapy. Furthermore, aptamer-functionalization could greatly increase the accumulation of nanoparticles within cancer cells and lead to better therapeutic effects. The results suggest that aptamer-functionalized semiconductor nanoparticles may have potential in the development of targeted photocatalytic and chemotherapy against cancer.

•Nanotextured GaN surface has been successfully fabricated by a facile chemical vapor deposition method.•UV light irradiation made the nanotextured GaN surface be superhydrophilic.•UV illumination greatly increased fibronectin (FN) adsorption, and then enhanced cell growth and adhesion significantly on nanotextured GaN surface.•We provide a novel approach to increase FN adsorption and cell growth at the nano/biointerface.Semiconductors are important materials used for the development of high-performance biomedical devices. Gallium nitride (GaN) is a well-known III-nitride semiconductor with excellent optoelectronic properties as well as high chemical stability and biocompatibility. The formation of tight interfaces between GaN substrates and cells would be crucial for GaN-based devices used for probing and manipulating biological processes of cells. Here we report a strategy to greatly enhance cell adhesion and survival on nanotextured GaN surface which was treated by UV illumination and fibronectin (FN) adsorption. Cell studies showed that the UV/FN treatment greatly enhanced cell adhesion and growth on nanotextured GaN surfaces. These observations suggest new opportunities for novel nanotextured GaN-based biomedical devices.

We report a general approach for the synthesis of large-scale gallium nitride (GaN) nanostructures by the graphene oxide (GO) assisted chemical vapor deposition (CVD) method. A modulation effect of GaN nanostructures on cell adhesion has been observed. The morphology of the GaN surface can be controlled by GO concentrations. This approach, which is based on the predictable choice of the ratio of GO to catalysts, can be readily extended to the synthesis of other materials with controllable nanostructures. Cell studies show that GaN nanostructures reduced cell adhesion significantly compared to GaN flat surfaces. The cell-repelling property is related to the nanostructure and surface wettability. These observations of the modulation effect on cell behaviors suggest new opportunities for novel GaN nanomaterial-based biomedical devices. We believe that potential applications will emerge in the biomedical and biotechnological fields.

Interfacing nanowires with living cells is attracting more and more interest due to the potential applications, such as cell culture engineering and drug delivery. We report on the feasibility of using photoresponsive semiconductor gallium nitride (GaN) nanowires (NWs) for regulating the behaviors of biomolecules and cells at the nano/biointerface. The GaN NWs have been fabricated by a facile chemical vapor deposition method. The superhydrophobicity to superhydrophilicity transition of the NWs is achieved by UV illumination. Bovine serum albumin adsorption could be modulated by photoresponsive GaN NWs. Tunable cell detachment and adhesion are also observed. The mechanism of the NW surface responsible for modulating both of protein adsorption and cell adhesion is discussed. These observations of the modulation effects on protein adsorption and cell adhesion by GaN NWs could provide a novel approach toward the regulation of the behaviors of biomolecules and cells at the nano/biointerface, which may be of considerable importance in the development of high-performance semiconductor nanowire-based biomedical devices for cell culture engineering, bioseparation, and diagnostics.Keywords: cell adhesion; gallium nitride; nano/biointerface; nanowire; protein adsorption; semiconductor;

We report a study of nanoribbons of quercetin, a phase I clinical trial anticancer drug, and their inhibitory effects on cancer cell proliferation. Novel quercetin nanoribbons have been prepared by atmospheric pressure physical vapor deposition (PVD). The nanostructures have been characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy, etc. Significantly enhanced solubility in PBS solution and increased drug release rate have been observed for quercetin nanoribbons in comparison to those of quercetin powder. The observed increase of inhibitory effects of quercetin nanoribbons on 4T1 cancel cell growth is correlated with an improvement in their solubility and drug release behavior.

We report that flower-like novel L-leucine micro/nanocrystals have been synthesized by a physical vapor deposition technique. The controllable synthesis of L-leucine micro/nanocrystals is very important for their pharmaceutical applications as drug carriers or excipients. Their morphologies have been controlled by adjusting the deposition position, deposition temperature and flux of the carrier gas. All of the micro/nanostructures have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectroscopy and atomic force microscopy. A growth model for the formation mechanism of the flower-like crystal structures is proposed. The coating of leucine micro/nanocrystals for a drug model system, quercetin, is also presented. Leucine micro/nanocrystals have great potential in pharmaceutical applications such as dispersibility enhancers. This coating design concept can also be used for a variety of active pharmaceutical ingredients.

We report on the synthesis of inorganic fullerene-like molybdenum disulfide (MoS2) nanoparticles by pulsed laser ablation (PLA) in water. The final products were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and resonance Raman spectroscopy, etc. Cell viability studies show that the as-prepared MoS2 nanoparticles have good solubility and biocompatibility, which may show a great potential in various biomedical applications. It is shown that the technique of PLA in water also provides a green and convenient method to synthesize novel nanomaterials, especially for biocompatible nanomaterials.Keywords: biocompatibility; biomedical applications; colloids; inorganic fullerene-like; nanoparticles; pulsed laser ablation

Bacterial infection is a worldwide health problem. Finding new potential antibacterial materials and developing advanced treatment strategies are becoming increasingly important and urgent. Herein, a versatile graphene-based photothermal nanocomposite was prepared for rapidly capturing and effectively eliminating both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and for destroying bacterial biofilms with near-infrared (NIR) irradiation. In this work, chitosan-functionalized magnetic graphene oxide (GO–IO–CS) was synthesized as a multifunctional therapy agent through a hydrothermal method. Chitosan could efficiently contact and capture bacteria by its positively charged surface functional groups, and graphene oxide could act as an effective photothermal killer to convert NIR light into local heat to enhance antibacterial activity. The super-paramagnetic properties of GO–IO–CS made it easy to separate and aggregate the bacteria, so improving the photothermal sterilization efficiency. GO–IO–CS was demonstrated to eliminate bacteria effectively after 10 min of NIR irradiation and to destroy bacterial biofilms. Furthermore, this antibiotic agent could be regenerated with an external magnet and reused in a subsequent antibacterial application.

A novel magnetic-enhanced colorimetric assay was constructed based on aptamer conjugated PtCo bimetallic nanoparticles (NPs) with high oxidase-like catalytic activity, high water solubility, low cell toxicity, and superparamagnetic properties. It was found that the incorporation of magnetic metal Co atoms into NPs could not only be facilitated for magnetic separation, but also resulted in the significantly improved oxidase-like catalytic activity of the nanoparticles for cancer-cell detection without the destructive H2O2. The present work demonstrates a general strategy for the design of multifunctional materials based on bimetallic nanoparticles for different applications, such as biosensors, nanocatalysts and nanomedicine.

Today cancer is one of the most life-threatening diseases in the world. The conventional cancer therapies, including surgery, chemo- and radiation therapies, have some disadvantages, such as limited efficiency and significant side effects. It is necessary to develop new therapeutic treatments. Herein, we integrated the targeted photocatalytic and chemotherapy in a multifunctional drug-delivery platform. The aptamer-functionalized ZnO nanoparticles (NPs) were successfully synthesized. The anti-cancer drug was loaded in the aptamer–ZnO NP system. In vitro cell cytotoxicity experiments showed that combined therapy had a higher rate of death of cancer cells compared to that of single photocatalytic or chemotherapy. Furthermore, aptamer-functionalization could greatly increase the accumulation of nanoparticles within cancer cells and lead to better therapeutic effects. The results suggest that aptamer-functionalized semiconductor nanoparticles may have potential in the development of targeted photocatalytic and chemotherapy against cancer.

The current cancer therapies in clinical practice demonstrate the need for improvements such as improving the efficiency and reducing the severe side effects. Herein, we integrated the targeted chemotherapy and photothermal therapy in a multifunctional drug-delivery platform. The targeting DNA aptamer (Apt)–modified graphene oxide–gold nanoparticle (GO–AuNP) composites were successfully synthesized. The doxorubicin (DOX)–loaded GO–AuNP–Apt system showed heat-stimulative and sustained release characteristics. In vitro cell cytotoxicity experiments showed that combined therapy had the highest rate of death of tumor cells compared to that of single photothermal therapy or chemotherapy. Furthermore, aptamer-modification could significantly enhance the accumulation of nanocomposites within cancer cells. Our study demonstrates that aptamer–modified GO–Au nanocomposites may have potential in the development of targeted photothermal therapy and chemotherapy against cancer cells.