Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer).
Gels are materials composed of a three-dimensional crosslinked polymer or colloidal network immersed in a fluid. They are usually soft and weak, but can be made hard and tough. Hydrogels are gels that contain more than 99.9% of water.
This protocol describes how to make and use a gelatin-based hypoxia-inducible hydrogel to inject or embed tissue or cells. This enables the cellular responses to controllable hypoxic gradients to be assessed in vitro and in vivo, e.g., in mice.
Most polymeric materials that show sol-gel transitions are unidirectional and stimuli-responsive systems. Here the authors show a block copolymer solution that undergoes autonomous and periodic sol-gel transitions under constant conditions.
Biophysical factors in an optimized three-dimensional microenvironment enhance the reprogramming efficiency of human somatic cells into pluripotent stem cells when compared to traditional cell-culture substrates.