The effects of scaffold thickness on tissue engineered cartilage in photocrosslinked poly(ethylene oxide) hydrogels

The thickness of human articular cartilage has been reported to vary from l ess than 0.5 up to 7 mm. Hence, tissue engineered cartilage scaffolds shoul d be able to span the thickness of native cartilage to fill defects of all shapes and sizes. In this study, we demonstrate the potential fur using pho topolymerization technology to encapsulate chondrocytes in poly(ethylene ox ide) hydrogels, which vary in thickness from 2 to 8 mm. Chondrocytes. encap sulated in an 8 mm thick, photocrosslinked hydrogel and cultured in vitro f or 6 weeks, remained viable and produced cartilaginous tissue throughout th e construct comparable to a 2 mm thick gel as seen both histologically and biochemically. In addition, the total collagen and glycosaminoglycan conten ts per wet weight of the 8 mm thick cell-polymer construct were 0.13 +/- 0. 01 and 0.25 +/- 0.03%, respectively, and did not vary significantly as a fu nction of spatial position in the construct. The histological evidence and the biochemical content were similar in all constructs of varying thickness . The results suggest that photocrosslinked hydrogels are promising scaffol ds for tissue engineering cartilage as cell viability is readily maintained : uniform cell seeding is easy to achieve; and the biochemical content of t he extracellular matrix is not compromised as the scaffold thickness is inc reased from 2 to 8 mm. (C) 2001 Elsevier Science Ltd. All rights reserved.