Hydroxyapatite reinforced collagen scaffolds with improved architecture and mechanical properties

作者：Kane Robert J; Weiss Bilka Holly E; Meagher Matthew J; Liu Yongxing; Gargac Joshua A; Niebur Glen L; Wagner Diane R; Roeder Ryan K^*

来源：Acta Biomaterialia, 2015, 17: 16-25.

DOI：10.1016/j.actbio.2015.01.031

• Bioactivity
• Collagen
• Hydroxyapatite
• Osteoinduction
• Scaffold

Hydroxyapatite (HA) reinforced collagen scaffolds have shown promise for synthetic bone graft substitutes and tissue engineering scaffolds. Freeze-dried HA-collagen scaffolds are readily fabricated and have exhibited osteogenicity in vivo, but are limited by an inherent scaffold architecture that results in a relatively small pore size and weak mechanical properties. In order to overcome these limitations, HA-collagen scaffolds were prepared by compression molding HA reinforcements and paraffin microspheres within a suspension of concentrated collagen fibrils (similar to 180 mg/mL), cross-linking the collagen matrix, and leaching the paraffin porogen. HA-collagen scaffolds exhibited an architecture with high porosity (85-90%), interconnected pores similar to 300-400 gm in size, and struts similar to 3-100 mu m in thickness containing 0-80 vol% HA whisker or powder reinforcements. HA reinforcement enabled a compressive modulus of up to similar to 1 MPa, which was an order of magnitude greater than unreinforced collagen scaffolds. The compressive modulus was also at least one order of magnitude greater than comparable freeze-dried HA-collagen scaffolds and two orders of magnitude greater than absorbable collagen sponges used clinically. Moreover, scaffolds reinforced with up to 60 vol% HA exhibited fully recoverable elastic deformation upon loading to 50% compressive strain for at least 100,000 cycles. Thus, the scaffold mechanical properties were well-suited for surgical handling, fixation, and bearing osteogenic loads during bone regeneration. The scaffold architecture, permeability, and composition were shown to be conducive to the infiltration and differentiation of adipose-derive stromal cells in vitro. Acellular scaffolds were demonstrated to induce angiogenesis and osteogenesis after subcutaneous ectopic implantation by recruiting endogenous cell populations, suggesting that the scaffolds were osteoinductive.

• 出版日期2015-4-15