Xinhuan Wang

Aptamer–conjugated graphene oxide–gold nanocomposites for targeted chemo-photothermal therapy of cancer cells

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.

Reduced aggregation and cytotoxicity of amyloid peptides by graphene oxide/gold nanocomposites prepared by pulsed laser ablation in water.

A novel and convenient method to synthesize the nanocomposites combining graphene oxides (GO) with gold nanoparticles (AuNPs) is reported and their applications to modulate amyloid peptide aggregation are demonstrated. The nanocomposites produced by pulsed laser ablation (PLA) in water show good biocompatibility and solubility. The reduced aggregation of amyloid peptides by the nanocomposites is confirmed by Thioflavin T fluorescence and atomic force microscopy. The cell viability experiments reveals that the presence of the nanocomposites can significantly reduce the cytotoxicity of the amyloid peptides. Furthermore, the depolymerization of peptide fibrils and inhibition of their cellular cytotoxicity by GO/AuNPs is also observed. These observations suggest that the nanocomposites combining GO and AuNPs have a great potential for designing new therapeutic agents and are promising for future treatment of amyloid-related diseases.

Cell-Capture and Release Platform Based on Peptide-Aptamer-Modified Nanowires

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.

Enhanced cell growth on nanotextured GaN surface treated by UV illumination and fibronectin adsorption

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.

Molybdenum Disulfide Nanoparticles as Multifunctional Inhibitors against Alzheimer’s Disease

The complex pathogenic mechanisms of Alzheimers 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.

GO-AgCl/Ag nanocomposites with enhanced visible light-driven catalytic properties for antibacterial and biofilm-disrupting applications.

Nanomaterials with visible light-driven photocatalytic activity have attracted much attention due to their excellent abilities in degradation of various organic pollutants as well as inactivating bacteria. Herein, graphene oxide (GO) enwrapped silver chloride/silver (AgCl/Ag) nanocomposites with high visible light absorption were designed and fabricated as efficient antibacterial agents. AgCl NPs were synthesized in the presence of GO first and Ag NPs were coated on AgCl surface by heat reduction to form GO-AgCl/Ag nanocomposites. The as prepared nanocomposites revealed improved stability, higher absorption properties in the visible light region. The enhanced antibacterial activity was observed by quantification of colony forming units (CFU) and morphological changes of bacteria. The antibacterial mechanism of GO-AgCl/Ag was also investigated by evaluating membrane permeability and ROS level. Moreover, GO-AgCl/Ag composites can eliminate bacterial biofilms more efficiently under visible light irradiation. Our results provide new insights into the design of new multifunctional systems for antibacterial applications.

Quercetin nanoparticles with enhanced bioavailability as multifunctional agents toward amyloid induced neurotoxicity

Quercetin (Que), as one of the most potent flavonoids, has gained appreciable attention in anti-fibrosis, anti-oxidation and other therapeutic research due to its numerous pharmacological and biological functions. However, low aqueous solubility, poor permeability and instability in physiological media have limited its widespread application in the pharmaceutical field. Herein, a facile method for fabrication of Que nanoparticles (NPs) has been developed by pulsed laser ablation (PLA). Que NPs exhibited homogeneous morphology with an average diameter of 50 nm and narrow distributions, which revealed enhanced solubility and drug release activity. Owing to the advance of NPs in modulating the amyloid fibrillation process as well as the anti-oxidative ability, Que NPs were applied to regulate Aβ42 assembly and they showed multifunctional effects: inhibiting Aβ aggregation, destabilizing Aβ fibrils, decreasing Aβ-induced oxidative stress and Aβ-mediated cytotoxicity. Thus, Que NPs with enhanced bioavailability may act as a multifunctional therapeutic agent toward amyloid-related diseases.