FIG. 2.

Mechanical characteristics of PG-1. (A) Scanning electron microscopic images of pullulan-gelatin hydrogel at 27× magnification (left panel) and 75× magnification (center panel). Images at 75× magnification were used to quantify pore sizes. Pore size distribution was plotted (right panel). Average pore size was 61.69 ± 2.76 μm (mean ± SEM) with a range of pore sizes from 20 to 200 μm. (B) The mass of PG-1 over time when submerged in pullulanase microbial is shown. Hydrogels could no longer be placed on a scale after 20 min due to significant degradation. (C) Image shows increase in hydrogel size after being incubated in PBS. Swelling percentage of pullulan-gelatin hydrogel ranged from 1812% ± 25.46%, 1758% ± 31.74%, and 1801% ± 43.49% (mean ± SEM) when incubated in PBS, fibroblast media, and keratinocyte media respectively. (D) Sample stress-strain curve for PG-1 is shown. Elastic modulus of the pullulan-gelatin material was 22.43 ± 4.54 kPa (mean ± SEM). PBS, phosphate-buffered saline; SEM, standard error of the mean. Color images available online at www.liebertpub.com/tea