Hydrogels with reversible chemical environments for in vitro cell culture.

Methods to reversibly control the chemical environment of hydrogels have application in three-dimensional cell culture to study cell proliferation， migration and differentiation in environments more representative of in vivo environments. Herein， we have developed a method to temporally control the chemical environment of agarose hydrogels through non-covalent attachment of peptide motifs. Streptavidin-GRGDS conjugates were immobilized in desthiobiotin-modified agarose hydrogels through the desthiobiotin-streptavidin interaction (K 10 M). Streptavidin-GRGDS was then displaced from the gel by the addition of biotin， which has a higher affinity for streptavidin (K 10 M). This process was repeated to sequentially and simultaneously immobilize different biomolecules and model compounds in hydrogels over the course of several hours to weeks. The influence of dynamic chemical environments on cellular activity was demonstrated by monitoring HUVEC tube formation for 30 h.