Provided herein are biocompatible hydrogel polymer matrices, which are prepared from biocompatible pre-formulations. The biocompatible pre-formulations comprise at least one nucleophilic compound, at least one electrophilic compound, and at least one cell. The biocompatible hydrogel polymer matrix is bioabsorbable and releases the cell at a target site, achieving a controlled delivery. The biocompatible hydrogel polymer matrix provides a solid support conducive for cell viability and functionality. The cells may grow on the hydrogel polymer surface of inside the hydrogel polymer matrix.
