A food-derived bioactive peptide that works as an important antioxidant in vivo could be used to remedy oxidative stress-related diseases. Alzheimer's disease (AD) is influenced by the accumulation and deposition of amyloid beta (Aβ) peptides in vivo, and such accumulation may worsen under conditions of oxidative stress. This study aimed to assess whether a tetrapeptide from maize, TPM, could protect Caenorhabditis elegans against Aβ-induced disease and to clarify the possible mechanism of such protection, as well as contribute to a model of oxidative stress that influences the process of Alzheimer's disease. These parameters were tested in a C. elegans model of full-length Aβ1-42 expression (GMC101). TPM at 10 mM alleviated Aβ-induced paralysis in GMC101 under oxidative stress and normal conditions. Further studies demonstrated that TPM can efficiently inhibit Aβ aggregation in vitro and scavenge reactive oxygen species (ROS) that accelerate the accumulation and deposition of Aβ peptides in vivo. In addition, Aβ1-42 dimer and Aβ1-42 trimer were down-regulated by TPM under both oxidative stress and normal conditions. Our observations lead to the hypothesis that the bioactive peptide, TPM, is a potential drug candidate that might efficiently alleviate the symptoms of AD.

Organic/inorganic nanohybrids, which integrate advantages of the biocompatibility of organic polymers and diversified functionalities of inorganic nanoparticles, have been extensively investigated in recent years. Herein, we report the construction of arginine-glycine-aspartic acid-cysteine (RGDC) tetrapeptide functionalized and 10-hydroxycamptothecin (HCPT)-encapsulated magnetic nanohybrids (RFHEMNs) for integrin αVβ3-targeted drug delivery. The obtained RFHEMNs were near-spherical in shape with a homogeneous size about 50 nm, and exhibited a superparamagnetic behavior. In vitro drug release study showed a sustained and pH-dependent release profile. Cell viability tests revealed that RFHEMNs displayed a significant enhancement of cytotoxicity against αVβ3-overexpressing A549 cells, as compared to free HCPT and nontargeting micelles. Flow cytometry analysis indicated that this cytotoxic effect was associated with dose-dependent S phase arrest. Finally, RFHEMNs exerted encouraging anti-cell-migration activity as determined by an in vitro wound-healing assay and a transwell assay. Overall, we envision that this tumor-targeting nanoscale drug delivery system may be of great application potential in chemotherapy of primary tumor and their metastases.Keywords: anti-cell-migration; antitumor efficacy; cell cycle; integrin targeting; magnetic nanohybrids; RGDC tetrapeptide

A tetrapeptide (Leu-Asp-Tyr-Glu) from maize (TPM) is a bioactive peptide. Here we reported that TPM extended the lifespan of Caenorhabditis elegans under heat and oxidative stress. Specifically, TPM (10 mM) increased the average longevity of C. elegans by 36.9% and 27.6% under heat stress (35 °C) and oxidative stress, respectively. Further studies demonstrated that the significant longevity-extending effects of TPM on C. elegans could be attributed to its in vitro and in vivo free radical-scavenging effects and its up-regulation of stress-resistance-related proteins, including superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2). Real-time PCR results showed that the up-regulation of ageing-associated genes such as daf-16, sod-3 and hsp-16.2, in addition to skn-1, ctl-1 and ctl-2, could also contribute to the stress-resistance effect of TPM. These results indicate that TPM can (or has the potential to) protect against external stress and extend lifespan under stress.Highlights► A teterapeptide from maize (TPM) extends the lifespan of C. elegans under heat and oxidative stress. ► TPM has strong free radical-scavenging effects in vitro and in vivo. ► TPM up-regulates the expression of heat shock protein HSP-16.2. ► TPM up-regulates the expression of superoxide dismutase-3 (SOD-3). ► TPM regulates the mRNA expression of ageing-associated genes in C. elegans.

A double-targeted magnetic nanocarrier based with potential applications in the delivery of hydrophobic drugs has been developed. It consists of magnetite (Fe3O4) nanoparticles encapsulated in self-assembled micelles of the amphiphilic copolymer MPEG–PLGA [methoxy poly (ethylene glycol)-poly (d,l-lactide-co-glycolide)], and was fabricated using the solvent-evaporation technique. The magnetic nanocarrier has a very stable core–shell structure and is superparamagnetic. Its cytotoxicity was evaluated using the MTT assay with three cell lines—HeLa, MCF-7, and HT1080; it exhibited no cytotoxicity against any tested line at concentrations of up to 400 μg/mL after incubation for 24 h. Its cellular uptake was studied by Prussian blue staining and by fluorescence microscopy after encapsulating a fluorescent probe (hydrophobic quantum dots) into the nanocarrier. Finally, the magnetic targeting property of the magnetic nanocarrier was confirmed by an in vitro test. Overall, the results obtained demonstrate the potential of the double-targeted nanocarrier for the intracellular delivery of hydrophobic drugs.Graphical abstractHighlights► A potential double-targeted magnetic nanocarrier for drug delivery was fabricated. ► Magnetic nanocarrier exhibits substantial stability and superparamagnetic property. ► Magnetic nanocarrier has no cytotoxicity to three tested cancer cell lines. ► Efficient cellular uptake of the magnetic nanocarrier by HeLa cells. ► Magnetic nanocarrier can accumulate at the targeted area under a magnetic field.

Functional nanostructures with high biocompatibility and stability, low toxicity, and specificity of targeting to desired organs or cells are of great interest in nanobiology and medicine. However, the challenge is to integrate all of these desired features into a single nanobiostructure, which can be applied to biomedical applications and eventually in clinical settings. In this context, we designed a strategy to assemble two gold nanoclusters at the ferroxidase active sites of ferritin heavy chain. Our studies showed that the resulting nanostructures (Au–Ft) retain not only the intrinsic fluorescence properties of noble metal, but gain enhanced intensity, show a red-shift, and exhibit tunable emissions due to the coupling interaction between the paired Au clusters. Furthermore, Au–Ft possessed the well-defined nanostructure of native ferritin, showed organ-specific targeting ability, high biocompatibility, and low cytotoxicity. The current study demonstrates that an integrated multimodal assembly strategy is able to generate stable and effective biomolecule–noble metal complexes of controllable size and with desirable fluorescence emission characteristics. Such agents are ideal for targeted in vitro and in vivo imaging. These results thus open new opportunities for biomolecule-guided nanostructure assembly with great potential for biomedical applications.

High quality water-soluble photoluminescent (PL) microspheres consisting of CdSe/ZnS quantum dots (QDs) and amphiphilic oligomers (polymaleic acid n-hexadecanol ester) were prepared by a versatile phase transfer method in an emulsion system. Controlled synthesis of different sizes of PL microspheres can be conducted by simply changing the initial oligomer concentration and/or the water/chloroform volume ratio. When the oligomer/QDs molar ratio exceeded 200:1, only oligomer-coated monodisperse CdSe/ZnS QDs without any aggregation were obtained. If the molar ratio ranged from 20:1 to 120:1, size-tunable PL microspheres could be obtained with a size range from 151 to 50 nm. Both of them exhibited high stability in aqueous solution under a wide range of pH, different salt concentrations, and thermal treatment at 100 °C. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, and fluorescence microscopy were used to characterize the PL microspheres and oligomer-coated monodisperse QDs. It is demonstrated that the stability of PL microspheres indeed depended on their dimensions. Larger PL microspheres could provide more hydrophobic protection for their interior QDs than smaller PL microspheres. A biosensor system (lateral flow immunoassay system, LFIA) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using CdSe/ZnS PL microspheres as fluorescence labels and a nitrocellulose filter membrane for lateral flow. The result showed that the PL microspheres were excellent fluorescence labels to detect HCG antigen in this LFIA system. The sensitivity of HCG antigen detection can reach 0.5 IU L−1, which is almost 20 times higher than traditional LFIAs using tinctorial labels.

High quality water-soluble photoluminescent (PL) microspheres consisting of CdSe/ZnS quantum dots (QDs) and amphiphilic oligomers (polymaleic acid n-hexadecanol ester) were prepared by a versatile phase transfer method in an emulsion system. Controlled synthesis of different sizes of PL microspheres can be conducted by simply changing the initial oligomer concentration and/or the water/chloroform volume ratio. When the oligomer/QDs molar ratio exceeded 200:1, only oligomer-coated monodisperse CdSe/ZnS QDs without any aggregation were obtained. If the molar ratio ranged from 20:1 to 120:1, size-tunable PL microspheres could be obtained with a size range from 151 to 50 nm. Both of them exhibited high stability in aqueous solution under a wide range of pH, different salt concentrations, and thermal treatment at 100 °C. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, and fluorescence microscopy were used to characterize the PL microspheres and oligomer-coated monodisperse QDs. It is demonstrated that the stability of PL microspheres indeed depended on their dimensions. Larger PL microspheres could provide more hydrophobic protection for their interior QDs than smaller PL microspheres. A biosensor system (lateral flow immunoassay system, LFIA) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using CdSe/ZnS PL microspheres as fluorescence labels and a nitrocellulose filter membrane for lateral flow. The result showed that the PL microspheres were excellent fluorescence labels to detect HCG antigen in this LFIA system. The sensitivity of HCG antigen detection can reach 0.5 IU L−1, which is almost 20 times higher than traditional LFIAs using tinctorial labels.