Adhesive cell tissue gels

A cell tissue gel, comprising one or more matrix molecules cross-linked with a cross-linking agent, and a quenching agent bound to a reactive group of the cross-linking agent, wherein the quenching agent contains a moiety that is capable of reacting with the reactive group of the cross-linking agent and the one or more matrix molecules contain one or more functional groups that are capable of cross-linking with the reactive group, the moiety being in an amount sufficient to react with any reactive group not cross-linked to the one or more functional groups and to reduce the cytotoxicity of the cell tissue gel cross-linked with the cross-linking agent, wherein the quenching agent is a polyglutamic acid and the cross-linking agent is not glutaraldehyde or N-hydroxysuccinimide ester, wherein the cell tissue gel lacks any fibroblast growth factor, and wherein the cytotoxicity of the cell tissue gel is reduced as compared to in the absence of the quenching agent.