Terahertz pulsed spectroscopy for optical and dielectric properties of demineralized bone matrix, collagen and hydroxyapatite

Abstract

DEMINERALIZED bone matrix (DBM) has osteoinductive potential functioning in many biological applications such as three-dimensional scaffold which assist new bone and cartilage growth by enhanced bioavailability of growth factors. Terahertz pulsed spectroscopy (TPS) was applied to investigate the optical and dielectric properties of camel femoral and cranial DBM, collagen type I, synthetic and natural hydroxyapatite powder (HA) in the range of 0.06-3.5THz. Terahertz (THz) absorption, refractive index (R.I) and dielectric properties (ε' and ε") were found to be intensely differentiated to control and demineralized bone. Results presented the THz absorption fingerprint of all studied materials. The natural HA revealed higher R.I, ε', and ε" values than both synthetic HA and collagen. Cranial DBM exhibited higher R.I compared to the control in all frequency ranges, whereas the femoral DBM behavior was frequency dependent. Demineralization produced significant increase in the values of ε' and ε". THz dielectric properties acted as a sensitive predictor to the composition and microstructure of bone in different biological applications. Amalgamation of Infrared Spectroscopy and THz spectroscopy together with TGA, ICP and EDX can offer deep insight into the sample properties.