TopoChip-Based High-Throughput Screening of Micropatterned Hydroxyapatite to Guide Stem Cell Behavior and Accelerate Bone Regeneration

Abstract

Surface topography is a key regulator of cell behavior, and high-throughput screening enables the systematic identification of patterns that direct specific cell fates. Hydroxyapatite (HA) is widely used as a bone substitute, yet precise fabrication of micropatterned HA surfaces and their role in contact guidance remain largely unexplored. Here, we report an HA-coated micropatterned TopoChip incorporating groove and pillar arrays with feature sizes ranging from 3 µm to 50 µm. Using bone marrow-derived mesenchymal stem cells (BMSCs), we screened cellular responses to these topographies and identified geometries that strongly promoted osteogenic differentiation. Grooves induced more pronounced contact guidance than pillars, with narrow ridges and small inter-pillar spacing driving cell elongation and alignment. These micropatterns enhanced focal adhesion formation and cytoskeletal tension, leading to upregulated osteogenesis. Importantly, the selected patterns accelerated bone regeneration in rat cranial defect models. This work establishes a facile strategy for fabricating HA micropattern libraries, elucidates the mechanisms by which topography directs osteogenesis, and provides design principles for orthopedic and dental biomaterials aimed at improving bone regeneration.