Green-Synthesized Nano-Hydroxyapatite using Terminalia arjuna enhancing Osteogenesis in MG-63 Cells: A Promising Approach for Bone Regeneration

Hydroxyapatite (HA) is a biologically unique extremely bioactive, osteoconductive and biodegradable calcium phosphate which is chemically and structurally similar to the mineral phase of natural bone. It is the material of choice for bone regeneration and tissue engineering applications. In the current work nano-hydroxyapatite (nHA) was synthesized by eco-friendly co-precipitation method using Terminalia arjuna bark extract known for its rich phytochemical profile, medicinal properties, reducing and stabilizing potential. The developed nHA materials were then characterized using a number of physicochemical techniques such as UV-Visible spectroscopy in which surface plasmon resonance was observed, X-ray diffraction was performed to calculate the crystallite size, Fourier Transform Infrared Spectroscopy was done to identify the major important functional groups. Particle size distribution analysis reveals the uniform distribution of nanoparticles in the size range from 50 to 100 nm. The antimicrobial activity of the developed nano particle was tested against both Gram-positive and Gram-negative bacterial strains showing strong anti-bacterial property. Besides, the nHA was electrospun into a nanofibrous scaffold through electrospinning which resembles the extracellular matrix (ECM) of native bone tissue. The developed scaffold was then subjected to mechanical characterization to ensure accuracy in stress/strain analysis and biocompatibility by simulated body fluid study. In vitro cytotoxicity testing was done to determine the toxicity of the developed scaffold. Cell viability of 77.16 % in 25 μg/mL sample concentration was observed against chemically induced bone loss. The early osteogenesis process was determined by alkaline phosphatase (ALP) activity in which the highest ALP production was observed as 5.123 ng/ml and late osteogenesis was evaluated by calcium mineralization assay by alizarin red S staining. The results showed that the synthesized nHA from T. arjuna bark extract exhibits osteoprotective effects with increased osteogenic differentiation of MG-63 cells. The results demonstrate the therapeutic potential of Terminalia arjuna mediated nano-hydroxyapatite as a next-generation bioceramic material with potential uses in bone grafts, orthopedic implants and scaffolds for tissue engineering.