Na Kong

A novel graphene nanodots inlaid porous gold electrode for electrochemically controlled drug release.

A uniform graphene nanodots inlaid porous gold electrode was prepared via ion beam sputtering deposition (IBSD) and mild corrosion chemistry. HRTEM, SEM, AFM and XPS analyses revealed the successful fabrication of graphene nanodots inlaid porous gold electrode. The as-prepared porous electrode was used as π-orbital-rich drug loading platform to fabricate an electrochemically controlled drug release system with high performance. π-orbital-rich drugs with amino mioety, like doxorubicin (DOX) and tetracycline (TC), were loaded into the graphene nanodots inlaid porous gold electrode via non-covalent π-π stacking interaction. The amino groups in DOX and TC can be easily protonated at acidic medium to become positively-charged NH3(+), which allow these drug molecules to be desorbed from the porous electrode surface via electrostatic repulsion when positive potential is applied at the electrode. The drug loading and release experiment indicated that this graphene nanodots inlaid porous gold electrode can be used to conveniently and efficiently control the drug release electrochemically. Not only did our work provide a benign method to electrochemically controlled drug release via electrostatic repulsion process, it also enlighten the promising practical applications of micro electrode as a drug carrier for precisely and efficiently controlled drug release via embedding in the body.

Real-time electrochemical monitoring of covalent bond formation in solution via nanoparticle–electrode collisions

We describe an alternative electrochemical technique to monitor covalent bond formation in real-time using nanoparticle-electrode collisions. The method is based on recognising the redox current when MP-11 functionalised chemical reduced graphene oxide (rGO) nanosheets collide with Lomants reagent modified gold microelectrode. This facile and highly sensitive monitoring method can be useful for investigating the fundamental of single-molecule reactions.

Size-dependent effects of gold nanoparticles on osteogenic differentiation of human periodontal ligament progenitor cells

Gold nanoparticles (AuNPs) have been reported to promote osteogenic differentiation of mesenchymal stem cells and osteoblasts, but little is known about their effects on human periodontal ligament progenitor cells (PDLPs). In this study, we evaluated the effects of AuNPs with various diameters (5, 13 and 45 nm) on the osteogenic differentiation of PDLPs and explored the underlying mechanisms. 5 nm AuNPs reduced the alkaline phosphatase activity, mineralized nodule formation and expression of osteogenic genes, while 13 and 45 nm AuNPs increased these osteogenic markers. Compared with 13 nm, 45 nm AuNPs showed more effective in promoting osteogenic differentiation. Meanwhile, autophagy was up-regulated by 13 and 45 nm AuNPs but blocked by 5 nm AuNPs, which corresponded with their effects on osteogenic differentiation and indicated that autophagy might be involved in this process. Furthermore, the osteogenesis induced by 45 nm AuNPs could be reversed by autophagy inhibitors (3-methyladenine and chloroquine). These findings revealed that AuNPs affected the osteogenic differentiation of PDLPs in a size-dependent manner with autophagy as a potential explanation, which suggested AuNPs with defined size could be a promising material for periodontal bone regeneration.