Evaluation of polycaprolactone scaffold degradation for 6 months <i>in vitro</i> and <i>in vivo</i>

TLDR

PCL is widely used in drug delivery and tissue engineering, and its in vivo degradation must be understood to support tissue regeneration. The study examined 3‑D PCL and PCL‑composite scaffolds by in‑vitro PBS immersion and in‑vivo rabbit implantation. After 6 months the scaffolds showed negligible molecular‑weight loss (<7 %), slight crystallinity and stiffness changes, and no adverse host reactions, while 2‑year implants demonstrated gradual molecular‑weight decline and bone regeneration. © 2008 Wiley Periodicals, Inc., J Biomed Mater Res, 2009.

Abstract

Abstract The use of polycaprolactone (PCL) as a biomaterial, especially in the fields of drug delivery and tissue engineering, has enjoyed significant growth. Understanding how such a device or scaffold eventually degrades in vivo is paramount as the defect site regenerates and remodels. Degradation studies of three‐dimensional PCL and PCL‐based composite scaffolds were conducted invitro (in phosphate buffered saline) and in vivo (rabbit model). Results up to 6 months are reported. All samples recorded virtually no molecular weight changes after 6 months, with a maximum mass loss of only about 7% from the PCL‐composite scaffolds degraded in vivo , and a minimum of 1% from PCL scaffolds. Overall, crystallinity increased slightly because of the effects of polymer recrystallization. This was also a contributory factor for the observed stiffness increment in some of the samples, while only the PCL‐composite scaffold registered a decrease. Histological examination of the in vivo samples revealed good biocompatibility, with no adverse host tissue reactions up to 6 months. Preliminary results of medical‐grade PCL scaffolds, which were implanted for 2 years in a critical‐sized rabbit calvarial defect site, are also reported here and support our scaffold design goal for gradual and late molecular weight decreases combined with excellent long‐term biocompatibility and bone regeneration. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009