Degradable poly-L-lysine-modified PLGA cell microcarriers with excellent antibacterial and osteogenic activity

The surface modification of polymeric materials has become critical for improving the bone repair capability of materials. In this study, we used a poly-L-lysine (PLL) coating method to prepare functional poly (lactic acid-glycolic acid) (PLGA) cell microcarriers, and bone morphogenetic protein 7 (BMP-7) and ponericin G1 were immobilized on the surface of microcarriers. The scanning electron microscopy (SEM), water contact angle measurement, and energy-dispersive X-ray spectroscopy (EDX) was used to analyse the surface morphology of PLL-modified PLGA microcarriers (PLL@PLGA) and their ability to promote mineralization. At the same time, the growth factor binding efficiency and antimicrobial activity of the microcarriers were studied. The effects of microcarriers on cell behaviors were evaluated by cultivating MC3T3-E1 cells on different microcarriers. The results showed that the hydrophilicity, protein adsorption, and mineralization induction capability of the microcarriers were significantly improved by PLL surface modification. The biological experiments revealed that BMP-7 and ponericin G1 immobilized-PLL modified microcarriers can effectively inhibit the proliferation of pathogenic microorganisms while enhancing the ability of the microcarriers to promote cell proliferation and osteogenesis differentiation. Therefore, we believe that PLL-modified PLGA cell microcarriers loaded with BMP-7 and ponericin G1 (PLL@PLGA/BMP-7/ponericin G1) have great potential in the field of bone repair.