Bioactive polyacrylamide hydrogels with gradients in mechanical stiffness

摘要: We propose a novel, single step method for the production of polyacrylamide hydrogels with gradient in mechanical properties. In contrast to already existing techniques such as UV photo-polymerization photomasks (limited penetration depth) or microfluidic mixers (complex chip), this technique is not suffering limitations. Young's modulus was varied by changing total monomer concentration hydrogel precursor solution. Using programmable syringe pumps, solution fed mold from 16 wt% down 5 over feeding time obtain compliance ranging 150 kPa 20 length 10 mm 2.5 mm. Polymerization achieved dual initiation system composed ammonium persulfate and N,N,N',N'-tetramethylethylenediamine, which were both through separate capillaries avoid premature polymerization. Functionalized model ligand collagen I, substrates bioactive supported attachment human foreskin fibroblasts (around 30% cells seeded attached after 1 h). A kinetic morphology study on homogeneous different stiffness's indicated that tend spread their final size within 2 h stiff substrates, while spreading much longer (ca. 4-5 h) soft substrates. These trends confirmed gradients, showing well end h, still had small area rounded morphology.