Reduction-responsive zwitterionic nanogels based on carboxymethyl chitosan for enhancing cellular uptake in drug release

Stimuli-responsive nanoparticles as drug carriers have promising applications in chemotherapy. To increase stability of nanogels in the bloodstream and to enhance intracellular drug uptake, reduction-responsive zwitterionic nanogels were prepared using carboxymethyl chitosan as a material. The preparation included modification of carboxymethyl chitosan and crosslinking by of N,N-Bis(acryloyl) cystamine. The nanogels possessed zwitterions of carboxyl and amino groups, and showed excellent non-fouling behavior against protein adsorption. In the presence of a reduction agent such as glutathione (GSH), the nanogels were dissociated due to scission of disulfide bonds in the crosslinking structure, leading to drug release in tumor cells. The nanogels were non-cytotoxic, biocompatible, biodegradable, and would be potentially used as anticancer drug delivery carriers in controlled release for enhancing cellular drug uptake.