GCSP research stipend | Fall 2025

Evaluation of Aging of Calcium and Phosphate Sol-gel Precursor Solutions of Conformal Orthopedic Hydroxyapatite (HA) Implant Coating Quality

Given developments in advanced biomaterials, there is a growing interest in replacing metal with non-metal fixation devices. This study is a continuation of an initial FURI project where the natural bioceramic, hydroxyapatite (HA), was synthesized by sol-gel chemistry technology using calcium nitrate tetrahydrate and triethyl phosphate precursors. The goal of this project is to determine if viscosity measurements, made at various times during the gelation process, is a useful indicator of HA-derived dip coatings. Sol gel-derived HA dip coatings, derived from sol-gel solutions at different gelation times and viscosities, and further processed with heat treatment using a muffled furnace, were evaluated for HA coating quality. Sol-gel precursor mixtures at various stages of gelation were evaluated using contact angle and Fourier Transform Infrared Spectroscopy (FTIR) measurements, while HA coating quality was assessed with microscopy and X-ray diffraction (XRD) measurements. HA dip coating quality was analyzed statistically to determine if viscosity measurement is a good indicator of sol-gel processing conditions and enhanced dip coating quality.