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.

In Situ Hydroxyapatite Synthesis Enhances Biocompatibility of PVA/HA Hydrogels

“…The method of HAp incorporation appears to affect the biological properties of scaffolds. Although an optimal pH is 11 for HAp formation in the bulk, in situ synthesis demand pH around 9, as Poursamar et al found out [12]. At higher pH, there are charges more radically formed on the -OH side groups, but the absorption of Ca 2+ ions to them is slower.…”

“…Unfortunately, it does not support cell attachment and due to insufficient protein absorption, biological bond formation is hindered. To avoid these shortcomings, PVA could be modified with other components [12,13].…”

Simultaneous incorporation of PTH(1–34) and nano-hydroxyapatite into Chitosan/Alginate Hydrogels for efficient bone regeneration

“…In addition, hydroxyapatite (HAP), a calcium phosphate bioceramic, is an essential component for bone regeneration [ [31] , [32] , [33] , [34] ]. Combining HAP with hydrogels enables emulation of the natural structures of bone and promotes bone regeneration [ [35] , [36] , [37] ]. The intrinsic mechanical properties of HAP and its interaction with bone tissues are intimately dependent on the size of HAP.…”

Functionalized Porous Hydroxyapatite Scaffolds for Tissue Engineering Applications: A Focused Review

“…Further, the formation of stoichiometric HAP is promoted by the PVA with the degree of hydrolysis and can act as the most desirable system in biomedical applications. Consequently, the composite hydrogels showed better biocompatibility, stability, and swelling properties for the cartilage defect repair …”

“…Consequently, the composite hydrogels showed better biocompatibility, stability, and swelling properties for the cartilage defect repair. 153 Through the photopolymerization process, PVA−glycidyl methacrylate and HAP nanocomposite hydrogels were reported by Zhou et al The developed composite hydrogel exhibits excellent compressive strength and tensile strengths of 0.4 MPa. Importantly, nanocomposites are cytocompatible to the L929 cell line and promote cellular attachment and proliferation to L929 cell lines.…”