Swelling and BSA Release Behaviors of pH Sensitive Hydrogel Beads

Hydrogel beads was prepared to detect the swelling behavior and kinetics in different pH solutions after bovine serum albumin (BSA) was carried. FTIR, TGA, XRD and polarizing microscopes were utilized to characterize their morphology. The results show that the hydrogel beads had the highest swelling ratio under the same conditions at pH 1.5 and their degradation was detected exclusively. The smallest swelling occurs at pH 6.8. The addition of an enzyme to the solution generally improves the swelling of beads at the test pH values and accelerates erosion at pH 1.5. The kinetics of BSA release revealed that its release is controlled by gel beads expansion and BSA diffusion at acidic pH 1.5 and pH 8.0, but at pH 6.8, mainly determined by the structural relaxation of the beads. Beads have a significant pH responsiveness, which provides an experimental basis for the development of different forms of delivery carrier.