Understanding the solubility and electrospinnability of gelatin using Teas approach in single/binary organic solvent systems

The aim of this study is to correlate the solubility and electrospinnability of gelatin in different organic solvent systems. Teas graph was employed using the Hansen parameters in this systematic study to map the solvents that dissolve and enable the electrospinning of gelatin. It was found that in some cases, the solvent dissolved gelatin but the solution was not spinnable. Increasing the hydrogen bonding force (f(h)) assisted in the electrospinning of the gelatin solution. Higher dispersion force (f(d)) improves the electrospinnability at lower concentration of gelatin. The viscosity of the solution of pure acetic acid (AA) is higher than the binary solution of 3:1 AA/water and 3:1 AA/tetrahydrofuran (THF) for the same concentration of gelatin; the higher viscosity enhanced the electrospinning properties. Interestingly, field-emission scanning electron microscopy arrayed that the effect of increasing the concentration of gelatin in the pure AA system resulted in the formation of thicker fibres, however, it induced the formation of uniform fibres in the 3:1 AA/water system, whereas beaded morphology was obtained when lower concentration of gelatin was used. The fibres obtained from electrospinning the solution of 3:1 AA/THF resulted in the formation of thicker and non-uniform fibres due to the low electrical conductivity as well as the high volatility of the solution. Attenuated total reflectance-Fourier transform infrared spectroscopy portrayed all the major peaks of gelatin in the electrospun fibres. However, widening of the Amide-A peak of gelatin was observed when the solvent system of formic acid and 3:1 AA/THF were used. Thermal study of the fibre mats depicts that the binary solvent system using AA is more suitable to obtain nanofibres with more analogous structure to pristine gelatin. The electrospun samples of gelatin in the different solvent systems did not exhibit any cytotoxity on the HeLa cell line. Teas graph can be used as a quick solvent selection tool to prepare electrospinning solutions of gelatin blended with synthetic polymers to obtain nanofibres for biomedical applications.

Automated summary

The aim of this study is to investigate the correlation between the solubility and electrospinnability of gelatin in different organic solvent systems. The Teas graph was employed to map the solvents that can dissolve and enable the electrospinning of gelatin. It was found that the hydrogen bonding force and dispersion force of the solvent influenced the electrospinning properties of gelatin. The concentration of gelatin in different solvent systems also affected the morphology of the fibers.