Bioinspired Bone Seed 3D-Printed Scaffold via Trapping Black Phosphorus Nanosheet for Bone Regeneration

Significance of endogenous mineralization in bone reconstruction is paramount, as it facilitates the accumulation of calcium ions for bone tissue deposition. However, conventional 3D-printed scaffolds lack the capacity for calcium ion enrichment and mineralization, coupled with their low bone inductive activity. Inspired from the development of natural plant seeds, a biomimetic 3D printing scaffold is developed by implanting photosensitive black phosphorus "bone seeds" (BS), guiding a sequential process mirroring rooting (osteoblast recruitment), sprouting (fibrous callus mineralization), flowering (osseous callus formation), and fruiting (callus plasticity). BS were trapped onto porous 3D polycaprolactone (PCL) scaffolds with aminated surfaces via electrostatic interactions between phosphates and amino groups, creating the PCL-BS scaffold that can actively capture calcium ions for accelerating the endogenous regeneration of critical bone defects. In vitro and in vivo experiments show that the PCL-BS scaffold has good biocompatibility and strong osteogenic ability for rapid new bone regeneration under near-infrared (NIR) stimulation. In addition, whole transcriptome sequencing analysis is performed to reveal the transcriptomic mechanism of BS involved in signal transduction and network regulation during bone regeneration. This NIR light-regulated biomimetic BS inspired by seed planting, introduces a pioneering concept in the design of 3D printing bone repair scaffolds.