Fig shows the SEM images of starch hydrogel

The three-dimentional (3D) porous nano-biocomposites from pure starch and SF nanofibers were prepared via particulate leaching and freeze drying methods. Potato starch (12 g) and different amounts of chopped electrospun SF nanofibers were added to 100 ml distilled water containing 75 µl ml−1 glutaraldehyde and stirred thoroughly for 20 min. Starch and SF nanofibers were mixed with different weight ratios of 100/0, 95/5, 90/10, and 85/15. Afterwards, the LB42708 of the solution was adjusted to 2 by adding drops of 1 N HCl to the SF nanofibers-starch suspension and heating it with continuous stirring at 80 °C. Prior to gelatinization, 65 wt% sugar (150–350 µm) was added to the paste, stirred carefully and then poured into 24-well tissue culture polystyrene plates. The casted mixture was cooled in refrigerator at 4 °C, frozen at −20 °C for 12 h and then freeze-dried at −55 °C for 48 h. In order to leach out the sugar, prepared samples were soaked in isopropanol (70%) for 4 days. Next, the samples were rinsed with 1% glycine solution to remove uncrosslinked glutaraldehyde and then washed several times with distilled water. The structural analysis of each scaffold after crosslinking by glutaraldehyde was investigated by FTIR-ATR. The internal morphology of starch-based scaffolds was observed by SEM. Using Image J software, the size of the pores in each sample, the total area of the pores in each cross section (AP), and the total area of each cross section (AT) were measured. The measurements were carried out from the five SEM images of each sample (n=5). Next, the porosity percentage of the fabricated scaffolds was calculated using the following equation [18]:equation(1)Porosity(%)=APATAs mentioned in the previous study, the swelling ratio and porosity of hydrogels have an vascular cylinder effect on the amount of biomimetic CaP deposition [14]. For determination the swelling ratio (SR), three disks (n=3) of each composition with the initial weight of (Wo) were soaked in deionized water (T=37 °C) for several hours and allowed to completely swell. Afterwards, the excess water was removed by filter paper and then weight (Ws). The SR (%) was measured based on the following equation [14]:equation(2)SR(%)=Ws−WoWo×100.