H2O2-sensitive delivery microparticles based on the boronic acid chemistry: (Phenylboronic –alginate derivative/dextran) system

Oxidative stress is mainly due to the accumulation of hydrogen peroxide (H2O2), enabling to distinguish between inflamed tissues from a healthy one. Hydrogen peroxide is then a very promising stimulus for targeted drug delivery to diseased tissue. Herein, we design a new bio-compatible and -degradable polymeric multilayer film stable in aqueous solution at physiological pH, but which is destabilized upon exposure to a critical hydrogen peroxide concentration. More precisely, we exploit the possibility to form "boronate ester" linkage between a boronic derivative (the phenylboronic acid-modified alginate) and a diol biopolymer (the dextran) as a driving force for the multilayer build-up. We show that the resulting LbL films present H2O2-responsiveness at physiological pH. The film disruption is induced in response to H2O2 addition which causes the breakage of the boronate ester bond under this oxidative condition. This strategy is then extended for the fabrication of H2O2-responsive microparticles (coating of the calcium carbonate microsphere). The porosity of these microparticles has been judiciously employed to load a probe (rhodamine b). This approach represents a complementary approach to biodegradable H2O2-triggered release systems.