Injectable supramolecular hydrogels based on host–guest interactions with cell encapsulation capabilities

Abstract

Injectable hydrogels, which can deliver cells or drugs directly to tissue sites by minimally invasive injection methods, have attracted considerable attention. In this work, using β-cyclodextrin-grafted alginate as the host polymer and adamantane-grafted polyacrylamide as the guest polymer, an injectable supramolecular hydrogel system was developed based on the host–guest interaction between β-cyclodextrin (βCD) and adamantane (Ad). Simple physical mixing and stirring methods allowed the hydrogels to be prepared in a short time (<1 min). The rheological and mechanical properties and microscopic morphology of the hydrogels were conveniently regulated by changing the grafting degree of βCD and Ad in alginate or polyacrylamide. The shear-thinning and self-healing properties induced by reversible host–guest interactions and a natural, plant-based polysaccharide endow the developed hydrogels with good injectability and biocompatibility, respectively. Experiments showed that the hydrogels effectively adhered to pork tissue. Moreover, human umbilical vein endothelial cells and human ovarian cancer cells encapsulated in the hydrogels showed good viability and three-dimensional distribution after being cultured for three days. Overall, the rapid preparation method and the advantages of injectability, self-healing and cytocompatibility endow the proposed injectable hydrogel system with great potential as a tissue engineering material.