Surface Design and Water Vapor-Adsorption Characteristics of Biomimetic Composite Materials Derived from Salmon Resource

Abstract

Biomimetic composites of hydroxyapatite (HAp) and collagen with fast bio-absorption and good biocompatibility were designed utilizing salmon bone and skin at 283-293 K and pH 7.5-7.9 by a dissolution-precipitation method. Simultaneously, dissolved-precipitated HAp (dp-HA) was prepared at pH 9-10 using the calcined bone. The HAp/collagen composites (HA-C) were constituted by Ca2+-deficient HAp, I type-collagen and gelatin. At the synthetic temperature of 283 K, collagen fiber and HAp microcrystals were seen, while at 293 K, frock like-agglomerated particles or fiber like-oriented columnar ones were observed depending on the composition ratio (H/C) of HAp to collagen. Specific surface areas and total pore volumes for the HA-C synthesized at 293 K clearly increased with increasing the H/C, although there were micro-and-meso-pores in the pore diameters of 3-30 nm. Concerning water vapor-adsorption isotherms at 298 K for the HA-C powders, hysteresis-curves of the amounts of water vapor adsorbed (V) were recognized in the adsorption-desorption processes. The V values increased with increasing the H/C under the low relative pressures (P/PS) of 0-0.3 that mean monolayer-adsorption of water molecule. However, for H/C=2.2, the V values were the highest under the high P/PS of 0.70-0.90 that mean multilayer-adsorption and the biggest hysteresis-curve was found under the P/PS of 0.45-0.60, suggesting that the HA-C (H/C=2.2) powder not only adsorb water molecule on the surfaces but also absorb one into the crystal structure. Accordingly, the biomimetic HA-C powders will be applied as water-absorbable adsorption materials for cosmetic products or bone-regeneration therapy.