Biomimetic Nanofiber Membranes Reprogram Macrophages For Improved Osteogenesis

The aim of this study was to develop novel polycaprolactone/laponite (PCL/LAP) nanofiber membranes (NFMs) with decellularized extracellular matrix (dECM) modification and to investigate their effects on macrophages polarization and their role in regulating the osteogenic differentiation of bone marrow stromal cells (BMSCs) through macrophages reprogramming. PCL/LAP-NFMs were prepared by electrospinning and optimized for bioactivity by dECM modification. Decellularization effects were verified by DNA, HYP and collagen assays. SEM and FTIR were used to characterize the physicochemical properties of NFMs. The biocompatibility of NFMs on macrophages were assessed by CCK-8, cytoskeleton staining and live/dead cell staining. Macrophages polarization markers (iNOS, CD206) and inflammatory factors (TNF-α, Il-1b, Il-6, Il-10) expression were detected by qPCR, Western blotting and immunofluorescence staining. Osteogenic effects were evaluated in a macrophages-BMSCs co-culture system by ALP activity, alizarin red staining, and osteogenic markers (Col1a1, Alpl, Runx2, Bmp2) expression. PCL/LAP-dECM-NFMs exhibited good biocompatibility. dECM modification significantly induced M2 macrophages polarization and inhibited the expression of pro-inflammatory factors. In co-culture experiments, PCL/LAP-dECM-NFMs promoted osteogenic differentiation of BMSCs, as evidenced by enhanced ALP activity, increased mineralization, and up-regulation of osteogenic markers expression. The dECM-modified biomimetic NFMs significantly promoted osteogenic differentiation by regulating macrophages polarization and constructing an immune microenvironment conducive to bone regeneration. This study provides an important experimental basis for the development of novel bone repair barrier membranes with immunomodulatory functions.