Control of cellular adhesiveness in an alginate-based hydrogel by varying peroxidase and H(2)O(2) concentrations during gelation.

An aqueous solution of alginate possessing phenolic hydroxyl (Alg-Ph) groups is gellable via a horseradish peroxidase (HRP)-catalyzed oxidative crosslinking reaction between Ph groups, consuming H(2)O(2) as an electron acceptor. This study evaluates the effect of H(2)O(2) and HRP concentrations on cellular adhesiveness and proliferation on the resultant enzymatically crosslinked Alg-Ph gels. After 4h of seeding, 81.1% of L929 fibroblast cells adhere to an Alg-Ph hydrogel prepared with 1 U ml(-1) HRP and 1mM H(2)O(2). Increasing the concentration of H(2)O(2) to 15 mM decreases the percentage of adhering cells to 28.4%. The cellular adhesion at this H(2)O(2) concentration is increased to 82.6% by increasing the HRP concentration to 10 U ml(-1). The cells adhering to the Alg-Ph hydrogels with higher cellular adhesiveness establish a confluent monolayer during 168 h of culture. A cell sheet can then be harvested within 5 min of immersion in a medium containing alginate lyase at 1.0 mg ml(-1). The harvested cell sheet re-adhere, and the cells contained in the sheet proliferate after being transferred to another cell culture dish. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.