The design of materials for cutaneous
wound dressings has advanced from passive
wound covers to bioactive materials that promote skin regeneration and prevent
infection. Crosslinked
poly(N-isopropylacrylamide) (
PNIPAAm)-based
hydrogels have been investigated for a number of biomedical applications. While these materials can be used for
drug delivery, limited cell interactions restrict their
biological activity. In this article, acryoyl-
lysine (A-Lys) was incorporated into poly(
ethylene glycol) crosslinked
PNIPAAm to enhance
biological activity. A-Lys could be incorporated into the
hydrogels to improve cellular interaction in vitro, while maintaining swelling properties and thermoresponsive behavior.
Polyhexamethylene biguanide, an
antimicrobial agent, could be encapsulated and released from the
hydrogels and resulted in decreased bacteria counts within 2 hours. Two in vivo animal
wound models were used to evaluate the
hydrogel wound dressing. First, application of the
hydrogels to a rodent cutaneous wound healing model resulted in significant increase in healing rate when compared with controls. Moreover, the
hydrogels were also able to decrease bacteria levels in an infected
wound model. These results suggest that
PNIPAAm hydrogels containing A-Lys are promising
wound dressings due to their ability to promote healing and deliver active antimicrobial drugs to inhibit
infection.