Hydrogels for wound management and tissue gluing have
to adhere to tissue for a given time scale and then disappear, either by
removal from the skin or by slow degradation in applications inside the body. Advanced
wound management materials also envision the encapsulation of therapeutic drugs
or cells to support the natural healing process. The design of hydrogels that
can fulfill all these properties with minimal chemical complexity, a stringent
condition to favor transfer into a real medical device, is challenging. Herein,
we present a hydrogel design with moderate structural complexity that fulfills a
number of relevant properties for wound dressing: it can form in situ and encapsulate
cells, it can adhere to tissue, and it can be degraded on demand by light
exposure under cytocompatible conditions. The hydrogels are based on starPEG
macromers terminated with catechol groups as crosslinking units and contain intercalated
photocleavable triazole nitrobenzyl groups. Hydrogels are formed under mild
conditions (HEPES buffer with 9-18 mM of sodium periodate as oxidant) and are
compatible with encapsulated cells. Upon light-irradiation, the cleavage of the
nitrobenzyl group mediates depolymerization, which enables on-demand release of
cells or debonding from tissue. The molecular design and obtained properties
are interesting for the development of advanced wound dressings and cell
therapies, and expand the range of functionality of current alternatives.
Photodegradable Tissue-Adhesive Hydrogels