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 crosslinking changed the effectiveness of pentoxifylline released from the scaffolds. Cs had the highest contact angle (83^o), followed by Alg/Cs/Ca (70°), Alg/Cs (63°), and Alg/Ca (52°). 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-α and 24-33% less IL-6 compared to cells cultured with other pentoxifylline-releasing scaffolds.