Environmentally responsive hydrogels with dynamically tunable properties as extracellular matrix mimetic

Hydrogels are hydrophilic polymers with three-dimensional cross-linked structure that swell in aqueous solutions without dissolving in them. Environmentally responsive hydrogels have the ability to change their conformation when a specific stimulus such as temperature, pH, light or enzymes is applied. Such hydrogels have been interesting for biomedical uses as they can deform in situ under physiological conditions and provide the advantage of convenient administration. Over the past decade, hydrogels have been studied as materials for the development of artificial extracellular matrices (ECMs). Recently the ability to utilize external stimuli to mimic the dynamic character of natural ECMs has been explored. The scope of this paper is to review the recent developments in stimuli-responsive hydrogels whose properties can be tuned on the time and length scales of cell development.