IO4-- stimulated crosslinking of catechol-conjugated hydroxyethylchitosan as a tissue adhesive

Abstract

Catechol-functionalized polymers are of particular interest because of their strong water-resistant adhesive properties. Hydroxymethyl chitosan (HECTS) has been used as an implantable biomaterial having good water solubility, biodegradability and biocompatibility. Here, hydrocaffeic acid (HCA) grafted HECTS (HCA-g-HECTS) was prepared through carbodiimide coupling and the tethered catechol underwent periodate (urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0003)-stimulated mono and double cross-linking with genipin. The gelation time of these cross-linked HCA-g-HECTS hydrogels decreased with increasing molar ratio of cross-linker to grafted catechol group, increasing temperature, or the addition of genipin. Under the same molar ratio of cross-linker to catechol, urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0004-induced cross-linked HCA-g-HECTS hydrogels exhibited much stronger storage modulus and temperature stability than hydrogels made by Fe3+-triggered cross-linking. The urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0005-stimulated HCA-g-HECTS hydrogels were biocompatible on a cellular level when the molar ratio of urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0006 to catechol group was less than 0.5:1. The hydrogels prepared with a 0.125:1 molar ratio of urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0007 to catechol group exhibited high adhesion strength of 73.56 kPa against wet rat skin, and a higher adhesion strength than sutures in a rat wound closure model. This biocompatible urn:x-wiley:15524973:media:jbmb34150:jbmb34150-math-0008-stimulated HCA-g-HECTS hydrogel may represent a promising new tissue adhesive.