Hydroxyapatite/Polyvinyl Alcohol Composite Hydrogels for Bone and Cartilage Tissue Engineering

Abstract

Composite hydrogels on the basis of hydroxyapatite (HAp) and polyvinyl alcohol (PVA) has been proposed as a promising materials for bone and cartilage tissue engineering. HAp/PVA composite hydrogels with phase ratio 50:50wt% and 70:30wt% were obtained via in situ wet chemical precipitation technique in combination with the freeze-thawing approach. The XRD studies of sintered products revealed that HAp/PVA composite hydrogels synthesized from PVA with degree of hydrolysis (DH) 98% and molecular weights (MW) 25 kDa and 78 kDa are more suitable for biomedical purposes due to the formation of stoichiometric HAp. Swelling studies indicated that HAp/PVA 50:50 (78 kDa, 88% and 98%) hydrogels after 24h of immersion swell ~4.25-6.5 times less than identical samples with phase composition of 70:30wt%, which is accounted to different number of intermolecular hydrogen bonds formed. After 16 subsequent freeze-thawing cycles (FTC), HAp/PVA 50:50 (78 kDa, 88% and 98%) hydrogels contain ~1.2 times higher content of crosslinked PVA than HAp/PVA 70:30 (78 kDa, 88% and 98%) hydrogel samples.