Modulation of cell proliferation and differentiation on implantable biomaterials using femtosecond laser micro/nano-patterning technology

Achieving efficient bone regeneration and robust osseointegration stands as the fundamental pursuit in the design of orthopedic implants. To address this need, the surface morphological design of biomaterial is proposed to improve cell-material interaction. This study investigated the behavioral responses of MC3T3-E1 cells to nano-textured micropatterns produced by femtosecond laser texturing treatment on TC4 alloy. It was demonstrated that laser micro/nano-patterning treatment not only did not attenuate the cytocompatibility and surface mechanical stability of the substrate, but also effectively improved the cell adhesion and proliferation due to the increased physical anchoring sites. To further investigate the regulatory mechanism, microgrooves, micropillars and labyrinth patterns with identical characteristic sizes and nano-textures were produced. It was found that cell proliferation behavior was closely related to the enhancement of surface energy/wettability dominated by nanoscale roughness and insensitive to the micrometer-scale topography of the substrate. However, cell osteogenic differentiation was influenced by the cell growth morphology on different surface micropatterns. The more severe the cell nucleus deformation, i.e., the smaller the axial ratio of the cellular nucleus, the stronger the osteogenic differentiation properties of the cells on the corresponding surface. This work provides experimental guidance and experience in the design and selection of surface morphology for orthopedic implants, contributing to their widespread application.