Porous and responsive hydrogels for cell therapy

Cell therapy is an emerging and promising regenerative approach by cell replacement for the treatment of diseases or injuries. Hydrogels, featuring high biocompatibility, tunable physicochemical properties, controllable structures, and multiple functionalization possibilities, have been developed as most-frequently-used cell reservoirs. Aiming at treating diseases or injuries with high efficiency, a series of porous and responsive hydrogels have been fabricated for the encapsulation of therapeutic cells. These cell-laden hydrogels have been applied in a broad range of pre-clinical researches of which results have demonstrated hopeful prospects in cell therapy. In this review, we highlight the recent progress of porous and responsive hydrogels used for cell encapsulation towards cell therapy. The hydrogels used for cell therapy are firstly classified. The porosity fabrication strategies of hydrogels are summarized and discussed. The responsive functionalities of hydrogels are surveyed, focusing on temperature-sensitivity, photo-sensitivity, pH-responsivity and biomolecule-sensitivity. Moreover, preclinical researches of hydrogels towards cell therapy, including the treatment of several diseases, such as diabetes mellitus, cancer, neuro disorders, cardiac diseases and bone injuries are discussed.