Jingying Li

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.

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.

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.

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 oxidase/peroxidase-like activities of aptamer conjugated MoS2/PtCu nanocomposites and their biosensing application

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.

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.

Synthesis of leucine micro/nanocrystals for pharmaceutical applications

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.