Modifications of alginate-based scaffolds and characterizations of their pentoxifylline release properties

Lyophilized chitosan scaffolds (Cs) and alginate scaffolds crosslinked with calcium (Alg/Ca), chitosan (Alg/Cs), and calcium and chitosan together (Alg/Cs/Ca) were tested for their contact angles, drug release properties, degradability, and compressional moduli. In vitro tests were done to observe how degrees of cross-linking changed the effectiveness of pentoxifylline released from the scaffolds. Cs had the highest contact angle (83 degrees), followed by Alg/Cs/Ca (70 degrees), Alg/Cs (63 degrees), and Alg/Ca (52 degrees). Alg/Cs/Ca had the highest compressional modulus (9.8 kPa), followed by Alg/Cs (6.3 kPa), Alg/Ca (2.7 kPa) and Cs (2.3 kPa). After 21 days, 2.4% Alg/Cs/Ca degraded in buffered saline while 8.7% of Alg/Ca degraded. The release efficacy of Alg/Cs/Ca was at least 11% less than those of the rest of other scaffolds. In vitro tests showed that activated macrophage cells cultured with Alg/Cs/Ca that released pentoxifylline produced 54-62% less TNF-alpha and 24-33% less IL-6 compared to cells cultured with other pentoxifylline-releasing scaffolds. (C) 2009 Elsevier Ltd. All rights reserved.