In this study, growth factor binding found in natural extra-cellular matrix (ECM) was mimicked by a modified polymer scaffold that could attract either Insulin-Like Growth Factor-I (IGF-I), a growth factor known to stimulate ECM production by chondrocytes, and Transforming Growth Factor-B1 (TGF-B1), a growth factor known to induce chondrogenesis in mesenchymal stem cells.

Short growth factor-binding peptides were synthesized and covalently attached to an alginate polymer scaffold. Using self-assembled monolayer (SAM) chemistry, these modified alginate layers were characterized using Imaging Ellipsometry (IE). Affinity of each growth factor for its respective synthetic peptide was quantified via Surface Plasmon Resonance (SPR). The density of binding peptides bound to alginate was determined using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). Computational diffusion modeling was used to design an ELISA-based diffusion experiment. Mesenchymal stem cells and chondrocytes were grown in chemically modified-alginate beads with and without added growth factor; modification increased ECM production in both kinds of cells. Thus, through this novel system of peptide-modified alginate scaffolds, growth factors were specifically but non-covalently retained by alginate, allowing for controlled release of growth factors.