Rational Design of PMPC/PDMC/PEGDA Hydrogel Micropatterns onto Polylactic Acid with Enhanced Biological Activity.

Polylactic acid (PLA) is one of the biodegradable materials that has been used in the areas of surgical healing lines, cancer treatment, and wound healing. However, the application of PLA is still rather limited due to its high hydrophobicity and poor antibacterial activity. In order to enhance the antifouling and antibacterial performances of PLA, here we modified the surface of PLA with various sizes of hydrogel micropatterns in negative or positive mode using plasma treatment, the photomask technique, and UV-graft polymerization. The hydrogel micropatterns consist of poly(ethylene glycol) diacrylate (PEGDA), poly(2-methacryloyloxyethylphosphorylcholine) (PMPC), and poly(methacryloyloxyethyltrimethylammonium chloride) (PDMC). Compared to PLA, the patterned PLA (PLA-PMPC/PDMC/PEGDA) shows obviously enhanced antifouling and antibacterial activities. For PLA-PMPC/PDMC/PEGDA with either positive or negative micropatterns, the antifouling and antibacterial properties are gradually increasing with decreasing the size of micropatterns. Compared with PLA-PMPC/PDMC/PEGDA bearing positive and negative micropatterns in the same size, the PLA-PMPC/PDMC/PEGDA with negative micropatterns exhibits slightly better biological activity and the PLA-PMPC/PDMC/PEGDA with 3 μm negative hydrogel micropatterns shows the best hydrophilicity, antifouling, and antibacterial properties. Combining the in vitro hemolysis assay, cytotoxicity, water absorption test, and degradation test results, it is suggested that the fabrication of hydrogel micropatterns onto the PLA surface could significantly improve biological activities of PLA. We expect that this work would provide a new strategy to potentially develop PLA as a promising wound dressing.