Chang-Yun Quan

Dual targeting of a thermosensitive nanogel conjugated with transferrin and RGD-containing peptide for effective cell uptake and drug release

In this paper, both arginine-glycine-aspartic acid (RGD)-containing peptide and transferrin (Tf) were conjugated to the thermosensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (poly(NIPAAm-co-PAAc)) nanogel to prepare a dual-targeting drug carrier. The obtained nanogel was characterized in terms of fluorescence spectroscopy, UV-vis spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). In order to track the dual-ligand conjugated nanogel, fluorescein isothiocyanate (FITC) was further conjugated to the nanogel. A cell internalization experiment showed that the dual-ligand conjugated nanogel exhibited obviously enhanced endocytosis by HeLa cells as compared with non-tumorous cells (COS-7 cells). The drug-loaded dual-ligand conjugated nanogel could be transported efficiently into the target tumor cells and the anti-tumor effect was enhanced significantly, suggesting that the dual-ligand conjugated nanogel has great potential as a tumor targeting drug carrier.

Fabrication of a novel pH-sensitive glutaraldehyde cross-linked pectin nanogel for drug delivery

A novel pH-sensitive nanogel based on pectin cross-linked with glutaraldehyde (PT-GA) was designed and synthesized for drug delivery. Transmission electron microscope observation shows that the nano-sized gel particles exhibit a spherical morphology. The optical absorbance study of nanogel suspension reveals its pH sensitivity. Cytotoxicity study shows that the nanogel has no apparent inhibitory effect on cells. The in vitro drug-release behavior of the drug-loaded nanogel particles in three kinds of media, i.e., simulated gastric fluid, simulated intestine fluid and simulated colon fluid, was studied. PT-GA nanogel exhibits a faster release at a high pH, and the release could be further accelerated in the presence of pectinolytic enzyme, indicating that the nanogel may be used for colon-specific drug delivery.

Galactosyl conjugated N-succinyl-chitosan-graft-polyethylenimine for targeting gene transfer

Through incorporating lactobionic acid (LA) bearing a galactose group to N-succinyl-chitosan-graft-polyethylenimine (NSC-g-PEI), NSC-g-PEI-LA copolymers were synthesized as gene vectors with hepatocyte targeting properties. The molecular weight and composition of NSC-g-PEI-LA copolymers were characterized using gel permeation chromatography (GPC) and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) respectively. Agarose gel electrophoresis assays showed good DNA binding ability of NSC-g-PEI-LA, and the particle size of the NSC-g-PEI-LA/DNA complexes were between 150 and 400 nm as determined by a Zeta sizer. The NSC-g-PEI-LA/DNA complexes observed by scanning electron microscopy (SEM) exhibited a compact and spherical morphology. The zeta potentials of these complexes were increased with the weight ratio of NSC-g-PEI-LA/DNA. NSC-g-PEI-LA has a lower cytotoxicity than PEI (25 kDa) and the toxicity decreased with increasing substitution of LA. The transfection efficiency of different complexes was evaluated by luciferase assay. Compared with PEI (25 kDa) and NSC-g-PEI/DNA, NSC-g-PEI-LA showed good transfection activity and cell specificity to HepG2 cells. The results suggested that NSC-g-PEI-LA has the potential to be used as a safe and effective targeting gene vector.