Glucose and pH dual-responsive concanavalin A based microhydrogels for insulin delivery.

Glucose and pH dual-responsive microhydrogels based on concanavalin A (Con A) were prepared and used for insulin delivery. The combination of the specific saccharide-binding affinity of Con A and the cationic groups of N-(2-(dimethylamino) ethyl)-methacrylamide (DMAEMA) led to dual-responsive systems. SEM, fluorescence microscopy and particle size analysis showed that the obtained microhydrogels had a dense surface morphology and an average size of 38 μm. The in vitro insulin release study revealed that the microhydrogels could quickly respond to the changes of glucose concentrations in the medium and small change in pH value of the environment. The kinetics of insulin release was analyzed by using empirical equation and the apparent diffusion coefficient was calculated according to a solution of Fick's second law. The released insulin was proved to remain active. The result suggested that this microhydrogel might find potential applications for self-regulated insulin delivery, actuators and separation systems with sensitivity to glucose.