Xiao Xi Yang

Antibacterials loaded electrospun composite nanofibers: release profile and sustained antibacterial efficacy

Synthetic polyacrylonitrile (PAN)/agar composite nanofibers were fabricated by introducing agar during the electrospinning process, and it was found that the nanofibers could be used for efficient, controlled drug release. Hydrophilic drugs such as ampicillin (AMC) were successfully encapsulated inside the agar, allowing the formation of uniform and smooth AMC/agar/PAN composite nanofibers. Cell viability assays showed that the as-prepared agar/PAN composite nanofibers had a good biocompatibility, and the antibacterial activity of the designed drug delivery system was investigated against Gram negative E. coli with a sustained release profile. The good biocompatibility and enhanced thermal properties—as well as the long-lasting antibacterial activity—of these agar/PAN composite nanofiber-containing drugs indicate their significant promise for a variety of potential medicinal applications. We believe that this approach could serve as a model technique in the fields of drug delivery and controlled release when considering the compatibility between polymers and drugs.

Gold nanoparticle-based enhanced ELISA for respiratory syncytial virus

Respiratory syncytial virus (RSV) mediates severe respiratory illness in infants and young children worldwide, and it is also a significant pathogen of the elderly and immune compromised. Due to the low infectious dose and high infectious rate of RSV, remarkably rapid and sensitive RSV detection is important for infection control and discovery of antiviral drugs. In this work, we described a highly sensitive enzyme-linked immunosorbent assay (ELISA) utilizing gold nanoparticles (AuNPs) for the detection of RSV. Gold nanoparticles were used as carriers of the signalling antibody anti-RSV–HRP (horseradish peroxidase) in order to achieve an amplification of the signal. Compared to conventional ELISA procedures, this assay resulted in higher sensitivity and shorter assay time in the range between 0.5 and 50 pg mL−1. The application of AuNPs to the enhanced ELISA showed acceptable reproducibility, stability, and could be readily applied to determination of other pathogens in clinical diagnostics.

Real-time imaging of intracellular drug release from mesoporous silica nanoparticles based on fluorescence resonance energy transfer

In this study, a targeted cancer therapy imaging and sensing system is designed based on doxorubicin (DOX)-loaded green fluorescent mesoporous silica nanoparticles (FMSN) conjugated with folic acid (FA), by linking with α-amine-ω-propionic acid hexaethylene glycol (NH2-PEG-COOH). An in situ formation method is adopted to prepare luminescent MSNs, which then act as the donor for the fluorescence resonance energy transfer (FRET), as their emission at 500 nm overlaps with the absorption of the acceptor DOX at 485 nm. NH2-PEG-COOH is conjugated to the outer surface of the FMSN at one end and modified by folic acid at the other, so that the formed mesoporous silica composite has the merits of fluorescence imaging, mesoporous nanostructure for drug loading, receptor-mediated targeting and real-time monitoring of intracellular drug release. It was found that the FA-grafted and PEGlated nanocomposite has excellent biocompatibility towards Hep2 cells, and that the cytotoxicity of the loaded-DOX nanoparticles, containing the folate targeting units in the folate-receptor-rich Hep2 cancer cells, is higher than that without folate targeting units, under the same conditions. When the resultant nanoparticles enter into the cells, the green fluorescence of FMSN gradually recovers along with the release of DOX, to achieve the purpose of real-time monitoring of intracellular drug release.

A cancer-targeted drug delivery system developed with gold nanoparticle mediated DNA–doxorubicin conjugates

Clinical therapies of cancers are generally unsatisfactory with poor patient compliance because of low therapeutic efficiency and strong side effects in normal tissues. To overcome these shortcomings and improve the efficacy of medicines, it is necessary to design some new targeting ligands, comparable to the folic acid ligand that is commonly used. Here we report a new drug delivery system for the targeted therapy of neuroblastoma cancer by functionalizing the surface of gold nanoparticles (AuNPs) with DNA that contains cellular prion protein (PrPC) aptamers. Owing to the specific identification between the aptamer and PrPC expressed on the surface of human bone marrow neuroblastoma (SK-N-SH) cells, the DNA–drug conjugates were delivered to the target cancer cells, and thus apoptosis of these cells occurred. The in vitro toxicity assay and fluorescence imaging results showed that the AuNP mediated DNA–doxorubicin conjugates (AuNPs–DNA(Dox)) could be demonstrated as a specific and effective therapeutic agent for neuroblastoma cancer.