A process for preparing three-dimensional hydrogel objects comprising living cells is disclosed. A cell suspension is provided, the suspension comprising a first hydrogel precursor, which exhibits a transition into a gel state by a reduction in temperature below the gel point, comprising a second hydrogel precursor, which is chemically cross-linkable by a non-cytotoxic cross-linking agent, and comprising living cells. The cell suspension is deposited onto a substrate by printing or plotting and cooled to a temperature below the gel point of the cell suspension to solidify the deposited cell suspension. Thereafter a cross-linking agent is added to the solidified cell suspension so as to induce chemical cross-linking of the second hydrogel precursor. In this process, initial structural stability is achieved rapidly by temperature-dependent gelation, while long-term stability is ensured by chemical cross linking. Also disclosed is a composition of matter comprising the first and second hydrogel precursor and living cells, and a device for carrying out the process.
