DEVELOPMENT OF A NOVEL AND BIODEGRADABLE BOROPHENE-MONETITE SCAFFOLD TO TARGET BONE HEALING

Despite limited tissue availability, longer surgical time, increased blood loss, and donor site morbidity, autografts remain the current gold standard to enhance bone growth and healing. Alternative synthetic and osteoconductive calcium-phosphate bioceramic implants, like monetite, have been used to enhance bone healing. Reinforcing bioceramic implants with 2D nanosheets has further improved biological performance and mechanical strength. Ultra-thin and large lateral dimensions of 2D nanostructures create larger surface areas with higher electron mobility and catalytic capabilities, aiding in the adhesion, growth, proliferation, and differentiation of osteoblasts. Borophene is a novel, thin, biocompatible, biodegradable, and graphene-like 2D nanosheet of boron atoms, with desirable properties including thermal and electrical conductivity, strong mechanical resistance, and flexibility. Boron is an essential micronutrient in humans, shown to modulate the Wnt/β-catenin signaling pathway and critically involved in bone healing and skeletal metabolism. Modulating this pathway remains a promising target to accelerate bone healing. We hypothesize that a biodegradable borophene-monetite implant increases osteoblast proliferation and differentiation to accelerate bone repair. Monetite was prepared from monocalcium phosphate monohydrate and β-tricalcium phosphate, while borophene was synthesized by mechanical exfoliation from Boron micropowder. Different ratios of borophene were mixed with monetite for implant fabrication. Physicochemical characterization was performed using ultra-bright Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and compressive mechanical strength testing. The in-vitro responses and osteodifferentiation patterns were assessed through cytoxicity, proliferation, ALP differentiation, and key mRNA expression markers at select timepoints over 21 days using a pre-osteoblastic MC3T3-E1 cell line. Gene expression analysis was performed select osteoblastic markers (osteonectin (Sparc), Runx2, osteocalcin (Bglap)). TEM and SEM imaging confirmed the successful synthesis of thin borophene nanosheets with a mean lateral size of 230nm. Physicochemical characterization confirmed homogenous distribution of borophene over monetite scaffolds with a significantly enhanced mechanical integrity without altering monetite crystallinity. MC3T3-E1 cells cultures demonstrated cell viability well over 70%, along with signicantly elevated proliferative activity, ALP differentiation, and gene expression of osteoblastic markers with patterns expected in osteodifferentation. Through facile and scalable exfoliation of borophene and successful mixing into monetite, our results demonstrate that a biodegradable implant combining these synthetic alternatives may promote osteogenesis through the Wnt/β-catenin pathway. With indispensable ions and beneficial structural properties, borophene remains a favorable candidate in reinforcing bioceramic implants as an accessible, less invasive, and cost-effective treatment modality compared to harvesting autografts.