Drug Release Mechanism of BSA-loaded Electrospun Fibers by AFM
用AFM研究静电纺丝负载药物的缓释机制

Experiments were carried out to study the drug delivery mechanism of bovine serum albumin(BSA) loaded chitosan(CS)-poly(ethylene oxide)(PEO) nanofibers and poly(L-lactic acid)(PLA)-CS nanofibers.Atomic force microscope(AFM) was used to observe the degradation and swelling behavior of fibers in PBS solution.As seen from the SEM images of scaffolds and drug release profiles,their BSA delivery mechanisms were different.96% BSA was released from CS-PEO nanofibers after 10 h and the structure was almost totally degraded in 1 d.AFM images showed a distinct degradation process of CS-PEO fiber and fiber diameter increasing from 0.727 to 1.43 μm from 10 to 120 min.So BSA releasing was mainly controlled by the rapid degradation of CS-PEO fibers.On the contrary,no obvious degradation was observed in the AFM or SEM images of PLA-CS nanofibers.The fiber diameter increased from 1.9 to 2.8 μm from 1 to 30 d,and the amount of BSA in solution was less than 50%.It demonstrated that the BSA delivery of PLA-CS fibers depended on the drug diffusion process.