Qiusen Han

Biocompatible inorganic fullerene-like molybdenum disulfide nanoparticles produced by pulsed laser ablation in water.

We report on the synthesis of inorganic fullerene-like molybdenum disulfide (MoS(2)) 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 MoS(2) 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.

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.

Optical Regulation of Protein Adsorption and Cell Adhesion by Photoresponsive GaN Nanowires

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.

PtCo bimetallic nanoparticles with high oxidase-like catalytic activity and their applications for magnetic-enhanced colorimetric biosensing

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.

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.

Molecular Tethering Effect of C-Terminus of Amyloid Peptide Aβ42

Amyloid peptides are considered to be the main contributor for the membrane disruption related to the pathogenesis of degenerative diseases. The variation of amino acids at the carboxylic terminus of amyloid peptide has revealed significant effects on the modulation of abnormal assemblies of amyloid peptides. In this work, molecular binding agents were tethered to the C-terminus of β-amyloid peptide 1-42 (Aβ42). The molecular interaction between Aβ42 and molecule tethers was identified at single molecule level by using scanning tunneling microscopy (STM). The mechanistic insight into the feature variation of the self-assembly of Aβ42 peptide caused by molecular tethering at C-terminus was clearly revealed, which could appreciably affect the nucleation of amyloid peptide, thus reducing the membrane disruptions.

Enhancement of biological activities of nanostructured hydrophobic drug species

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.

Porous Pt/Ag nanoparticles with excellent multifunctional enzyme mimic activities and antibacterial effects

Enhancing the activity of Pt-based nanocatalysts is of great significance yet a challenge for the oxygen reduction reaction (ORR). In this work, a series of porous Pt/Ag nanoparticles (NPs) were fabricated from regular PtxAg100–x (x = 25, 50, 75) octahedra by a facile and economical dealloying process. Remarkable enhancement in multiple enzyme-mimic activities related to ORR was observed for the dealloyed Pt50Ag50 (D-Pt50Ag50) NPs. This effect can be attributed to the resulting Pt-rich surface structure, increased surface area, and a synergistic effect of Pt and Ag atoms in the D-Pt50Ag50 NPs. Furthermore, the D-Pt50Ag50 NPs exerted excellent antibacterial effects on two model bacteria (gram-negative Escherichia coli and gram-positive Staphylococcus aureus). The present work represents a significant advance in the exploration of the relation between controllable synthesis of high-quality nanoalloys and their novel catalytic properties for various promising applications, including catalysts, biosensors, and biomedicine.

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.

Synergistic Inhibitory Effect of Peptide–Organic Coassemblies on Amyloid Aggregation

Inhibition of amyloid aggregation is important for developing potential therapeutic strategies of amyloid-related diseases. Herein, we report that the inhibition effect of a pristine peptide motif (KLVFF) can be significantly improved by introducing a terminal regulatory moiety (terpyridine). The molecular-level observations by using scanning tunneling microscopy reveal stoichiometry-dependent polymorphism of the coassembly structures, which originates from the terminal interactions of peptide with organic modulator moieties and can be attributed to the secondary structures of peptides and conformations of the organic molecules. Furthermore, the polymorphism of the peptide-organic coassemblies is shown to be correlated to distinctively different inhibition effects on amyloid-β 42 (Aβ42) aggregations and cytotoxicity.