Novel pH-tunable nontoxic hydrogels of pyrrole-2-carboxylic acid and ethylenediamine derivatives: synthesis and characterization

Abstract

ABSTRACT In this study, attention has been paid to synthesize and investigate pH-sensitive biopolymeric hydrogel from renewable resource-based monomers such as citric acid, pyrrole-2-carboxylic acid, and ethylenediamine through two-step condensation polymerization. The formation of hydrogel and structure of hydrogel were confirmed by Fourier-transform spectroscopy and nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR) analyses. Thermal stability and glass transition temperature of hydrogel were analyzed by thermogravimetric analysis and differential scanning calorimetry analysis. Swelling studies of the hydrogel at various pH media ranging from 3.0 to 10.0 have also investigated. The swelling behavior of hydrogel increased in acidic media than in basic media. Scanning electron microscopic analysis revealed the spherical shape and porous nature of the hydrogel. The antibacterial activity of hydrogel was investigated against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial species at different concentrations. The cytotoxicity study of the hydrogel has been carried out using MTT assay method. Hence, the biopolymeric hydrogel with smart pH sensitivity may be considered an excellent candidate for industrial, environmental, and biological applications.