Fabrication and evaluation of a bilayer hydrogel-electrospinning scaffold prepared by the freeze-gelation method

This study presents a bilayer structure as a skin scaffold comprised of an electrospun sheet layer made of polycaprolactone and polyvinil alcohol and a porous hydrogel layer made of chitosan and gelatin. The hydrogel layer was fabricated by employing the freeze-gelation technique. The bilayer structure was achieved by pouring the hydrogel solution on the electrospun sheet at the bottom of a mold followed by the freeze-gelation technique to obtain a porous structure in the hydrogel. The hydrogel and hydrogel-electrospun samples were characterized by scanning electron microscopy, swelling, tensile strength, in vitro and in vivo analyses. From a mechanical strength standpoint, the combination of hydrogel and electrospun layers produced 110 and 133% increases in mean tensile strength and elastic modulus values, respectively compared to the single layer hydrogel sample. While the results of swelling and cell proliferation tests did not yield significant differences between the two groups, the bilayer scaffold performed better considering the results of the in vivo analysis. It was also seen that there was a good connection between the two layers in the bilayer scaffold, making the necessary manipulations and clinical handling convenient.