In Vitro Degradation of PHBV Scaffolds and nHA/PHBV Composite Scaffolds Containing Hydroxyapatite Nanoparticles for Bone Tissue Engineering

Abstract

This paper investigated the long-termin vitrodegradation properties of scaffolds based on biodegradable polymers and osteoconductive bioceramic/polymer composite materials for the application of bone tissue engineering. The three-dimensional porous scaffolds were fabricated using emulsion-freezing/freeze-drying technique using poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) which is a natural biodegradable and biocompatible polymer. Nanosized hydroxyapatite (nHA) particles were successfully incorporated into the PHBV scaffolds to render the scaffolds osteoconductive. The PHBV and nHA/PHBV scaffolds were systematically evaluated using various techniques in terms of mechanical strength, porosity, porous morphology, andin vitrodegradation. PHBV and nHA/PHBV scaffolds degraded over time in phosphate-buffered saline at 37°C. PHBV polymer scaffolds exhibited slow molecular weight loss and weight loss in thein vitrophysiological environment. Accelerated weight loss was observed in nHA incorporated PHBV composite scaffolds. An increasing trend of crystallinity was observed during the initial period of degradation time. The compressive properties decreased more than 40% after 5-monthin vitrodegradation. Together with interconnected pores, high porosity, suitable mechanical properties, and slow degradation profile obtained from long-term degradation studies, the PHBV scaffolds and osteoconductive nHA/PHBV composite scaffolds showed promises for bone tissue engineering application.

A porous medium‐chain‐length poly(3‐hydroxyalkanoates)/hydroxyapatite composite as scaffold for bone tissue engineering

“…The crystallinity of the P(3HO‐ co ‐3HHX) scaffold was decreased after composite formation indicating that crystal structures of both P(3HO‐ co ‐3HHX) and HA have changed after composite formation. Similarly, it was reported that addition of HA particles has led to lower degree of crystallinity of the PHBV matrix in composite scaffold . The XRD peaks, (211) and (300) were shifted to higher 2θ values in case of P(3HO‐ co ‐3HHX)/HA composite as compared to pure HA (i.e.…”

Third generation poly(hydroxyacid) composite scaffolds for tissue engineering

“…Blending of PHB with HA resulted in enhanced osteoblastic response compared to pure PHB owing to increased surface roughness and porosity . Scaffolds fabricated using an emulsion‐freezing/freeze‐drying technique was found to possess uniform pore structures with average pore sizes of 297 and 210 µm and porosity of 77 and 83% for PHBV and the PHBV/10% (w/w)HA composite respectively which were optimum features for osteoblasts . As reported previously, osteoblasts have a preferred pore size ranging from 200 to 400 pm diameter for enhanced migration, attachment and proliferation since the curvature of these pores provides optimum compression and tension on the cell's mechanoreceptors .…”

Comparison on in Vitro Degradation of Polycaprolactone and Polycaprolactone/Gelatin Nanofibrous Scaffold

“…Nanofibrous scaffolds were blotted dry with tissue paper to remove excess water and weighted. Water uptake of nanofibrous scaffolds was calculated using the following equation 1 [12].…”