Figure 2.

(A) Primary human NP cells attach to soft LM-111 coupled substrates (0.3 kPa polyacrylamide; left image) as rounded cells forming multi-cell clusters, while cells attaching to stiff (14 kPa; right image) substrates may elongate and form fewer cell clusters. (B) PAAm gels were formed with varying bisacrylamide ratios to achieve compressive moduli of 0.3 kPa (soft) and 14 kPa (stiff) as measured by atomic force microscopy. Conditions not connected by the same letters are significantly different from each other (p<0.0001, Mann-Whitney test). SD are shown. (C) Representative confocal Z-stack images of fluorescently labeled peptides conjugated to polyacrylamide gel. Peptides (green, FITC) and cells (red, mCherry) are shown in relation to each other, superimposed over a scaled diagram of the polyacrylamide gel (top). A three-dimensional isometric confocal image illustrates the even distribution of peptides throughout the gel (bottom). (D) Peptide functionalized substrates were found to have equivalent peptide densities on soft and stiff gels, with differences that vary with the amount of applied peptide. All studies were performed at the highest degree of peptide functionalization, 0.1 mM. SEM are shown.