LAUSR

Abstract This paper describes our recent findings of our on-going research on newberyite (NB, MgHPO4.3H2O), an important bio-ceramic in the MgO-P2O5 binary system. It reports the “Processing-Structure-Property” correlation results of novel multi-functional NB coatings on benchmark Ti6Al4V. The motivation behind this study is to seek newer and multi-functional uses of magnesium phosphates (MgPs) in orthopedics. Therefore, as opposed to extensively explored calcium phosphate (CaP) coatings, one of the prime novelties of this work lies in the development and evaluation of NB coatings to improve osseointegration as an alternative material. The fabrication aspect involves a microwave irradiation technique to synthesize the coatings within a short time. Furthermore, given the havoc created by surgical site infections (SSIs) in orthopedics, efforts have been made for the first time to synthesize single-phasic, antibacterial NB coatings. This is achieved by doping silver (Ag) into NB (Ag-NB) with the help of microwaves. Physical property evaluations such as X-ray diffraction analysis revealed the successful formation of crystalline, single-phase Ag-NB coatings. Scanning electron microscopy (SEM) confirmed the formation of about 50 μm thick coatings comprising of dense, compact, intricate crystals with orthorhombic and tabular-hexagonal shape. Most importantly, in vitro antibacterial assays indicated satisfactory bacteriostatic and bactericidal functionalities of the Ag-NB coatings against both gram-negative Escherichia coli and gram-positive Staphylococcus aureus within 5 h of incubation. This highlights their high efficiency in inhibiting SSIs. Cytocompatibility assays showed no signs of cytotoxicity in the coatings with healthy MC3T3 pre-osteoblast proliferation. Finally, high levels of osteocalcin (OCN) asserted the coatings' high biomineralization capability. Overall, this study proves that multi-functional Ag-NB coatings synthesized with microwaves can be potential alternatives to conventional CaP based coatings.