Biodegradation and in vivo biocompatibility of a degradable, polar/hydrophobic/ionic polyurethane for tissue engineering applications

• Published in: Biomaterials Vol. 32; no. 26; pp. 6034 - 6044
• Main Authors: McBane, Joanne E, Sharifpoor, Soroor, Cai, Kuihua, Labow, Rosalind S, Santerre, J. Paul
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.09.2011
• Subjects: Advanced Basic Science; Animals; Biocompatibility; Biocompatible Materials - adverse effects; Biocompatible Materials - metabolism; Biodegradation; Dentistry; Male; Microscopy, Electron, Scanning; Polylactic glycolic acid; Polyurethane; Polyurethanes - adverse effects; Polyurethanes - metabolism; Porosity; Porous scaffold; Rat subcutaneous implant; Rats; Rats, Wistar; Tissue Engineering - methods; Biodegradation; Rat subcutaneous implant; Biocompatibility; Porous scaffold; Polylactic glycolic acid; Polyurethane
• DOI: 10.1016/j.biomaterials.2011.04.048
• ISSN: 0142-9612

Abstract A degradable, polar/hydrophobic/ionic polyurethane (D-PHI) scaffold was optimized in in vitro studies to yield mechanical properties appropriate to replicate vascular graft tissue while eliciting a more wound-healing phenotype macrophage when compared to established materials. The objectives of this study were to characterize the biodegradation ( in vitro and in vivo ) and assess the in vivo biocompatibility of D-PHI, comparing it to a well-established, commercially-available scaffold biomaterial, polylactic glycolic acid (PLGA), recognized as being degradable, non-cytotoxic, and showing good biocompatibility. PLGA and D-PHI were formed into 6 mm diameter disk-shaped scaffolds (2 mm thick) of similar porosity (∼82%) and implanted subcutaneously in rats. Both PLGA and D-PHI scaffolds were well-tolerated at the 7 d time point in vivo. In vitro D-PHI scaffolds degraded slowly (only 12 wt% in PBS in vitro after 120 d at 37 °C). In vivo , D-PHI scaffolds degraded at a more controlled rate (7 wt% loss over the acute 7 d implant phase and subsequently a linear profile of degradation leading to a 21 wt% mass loss by 100 d (chronic period)) than PLGA scaffolds which showed an initial more rapid degradation (14 wt% over 7 d), followed by minimal change between 7 and 30 d, and then a very rapid breakdown of the scaffold over the next 60 d. Histological examination of D-PHI scaffolds showed tissue ingrowth into the pores increased with time whereas PLGA scaffolds excluded cells/tissue from its porous structure as it degraded. The results of this study suggest that D-PHI has promising qualities for use as an elastomeric scaffold material for soft TE applications yielding well integrated tissue within the scaffold and a controlled rate of degradation stabilizing the form and shape of the implant.