Synthesis of core-crosslinked zwitterionic polymer nano aggregates and pH/Redox responsiveness in drug controlled release

A new kind of core-crosslinked zwitterionic polymer nano aggregates was prepared by two steps: (1) terpolymers of lipoic acid, polyethylene glycol diglycidyl ether and L-lysine were prepared, forming nano aggregates with hydrodynamic radius of 80 nm-183 nm by self-assembly; (2) the crosslinking of the nano aggregates took place through a reaction of side chain group in lipoic acid structural unit with 1,4-dimercaptothreotol, producing zwitterionic polymer core-crosslinked nano aggregates. The aggregates were stable against dilution and protein adsorption, and they demonstrated good pH/redox dual-responsiveness due to the introduction of disulfide bonds and zwitterionic groups to the nano aggregates. Doxorubicin (DOX) was loaded into the nano aggregates for controlled release. The drug-loaded nano aggregates exhibited obvious pH and reduction sensitivities in response to the environmental conditions in tumor cells. The nano aggregates were biocompatible and could be potentially applied as anticancer drug vehicles for enhancement of cellular uptake of anticancer drugs.