Fabrication of superparamagnetic nanofibrous poly(l-lactic acid)/γ-Fe₂ O₃ microspheres for cell carriers

Nanofibrous poly(l-lactic acid) (PLLA) microspheres are extensively studied to be used as cell carriers in the field of tissue engineering because the unique structure can promote cell proliferation and migration. But as injectable scaffold materials, PLLA microspheres easily run off to the soft tissue space because of the lack of cohesive force. It will affect the treatment efficiency and even cause additional inflammatory response. In order to overcome this disadvantage, superparamagnetic γ-Fe₂ O₃ nanoparticles assisted with oxidative polymerization of dopamine were used for surface modification of PLLA microspheres in this study. The results showed that this surface modification had no obvious cytotoxicity, and the modified microspheres possessed the ability to carry seed cells to controllably move to the defect sites with the guidance of magnetic field, which may be able to increase the repair efficiency. Moreover, the characteristic nanofibrous structure was not destroyed after modification, which was able to promote biological activity of cells. This work provides a novel way to produce superparamagnetic nanofibrous microspheres designed for cell microcarriers. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 511-520, 2019.