Prolonged or extended release of bioactive protein is achieved using an affinity-based approach which exploits the specific binding of Src homology 3 (SH3) domain with short proline-rich peptides. Specifically, methylcellulose was modified with SH3-binding peptides (MC-peptide) with either a weak affinity or strong affinity for SH3. Controlled release of chondroitinase ABC (ChABC) is also described.