STUDY OF HYDROXYAPATITE NANO COMPOSITES WITH PHOTOLUMINESCENCE PROPERTIES

Abstract

Hydroxyapatite (HAp) is the major inorganic component in human bones and well known for its biocompatibility. It has been widely prepared in many forms for orthopedic and dental applications. Color-center-doped HAps are also prevalently used as fluorescent materials. Further, HAp based photoluminescent material might be an ideal agent for bioimaging. Moreover, self-assembly of HAp in calcium- and phosphate-containing solutions gains a lot of attention because organic–inorganic HAp hybrids can be tailor-made. In this study, the author used a biomimetic process to synthesize organic–inorganic HAp nano hybrid at room temperature. The natural and synthesized polymeric templates used to prepare the organic–inorganic HAp hybrids were collagen, PEG–PLGA (di block), and PEG–PLGA–PEG (tri block), respectively. X-ray diffraction (XRD) diagrams revealed that the synthesized powders had crystalline HAp phase, and transmission electron microscope (TEM) photographs showed their nano grain structure. Characterization using XRD, TEM, and Fourier transform infrared spectrometer (FTR) indicated the existence of crystalline HAp phase and the variation in HAp shape versus different polymers in the composite powders. The measurement of photoluminescent (PL) spectra used a 325 nm He–Cd laser as source. The di HAp and tri HAp emitted light with a wide range of wavelength from 350 to 550 nm, much stronger than pure HAp. Collagen alone emitted brighter fluorescence peaked around 410 nm but was quickly quenched, while collagen–HAp composite powders emitted sustaining PL light peaking around 415 nm. The developed PL bioceramics are of great potential in bio sensing and bio optoelectronics.