Peptide and Gel Synthesis and Cell Seeding

Polynipaam gels were synthesized and modified with GRGDS peptide as described previously [3]. These lyophilized hydrogels contract volumetrically by approximately 45% when heated from 34°C to 37°C in medium containing 10% fetal bovine serum, and their average pore size changes from approximately 2398 ± 211 μm to 1618 ±108 μm, respectively, as described previously [3]. These gels upon sterilization were coated overnight with Collagen VI at a concentration of 100 ug/ml. A cell pellet consisting of approximately 1×10⁶ Murine BMD-MSCs was carefully injected within the pores of the gel construct using a 25 gauge syringe needle under a dissection microscope, and placed in an incubator set at 34°C and 5% CO₂ overnight. These gels were either kept in the 34°C incubator as a control in their non-shrinking form or moved to an incubator set at 37°C with 5% CO₂ where they subsequently shrank.