Supramolecular hydrogels as a captivating class of soft materials have attracted considerable attention across disciplines encompassing in fields of biology, materials, environment, and biomedicine science. The hydrogels derived from low molecular weight gelators sourced from biological molecules hold notable significance importance due to their smart responsiveness to external stimuli and excellent biocompatibility and biodegradability, such as amino acids, peptides, bile acids, and their derivatives.1,2
Supramolecular hydrogels were prepared in mixtures of both the biological surfactant sodium deoxycholate (NaDC) and alkali metal chlorides (LiCl, NaCl, KCl, RbCl, CsCl) in aqueous solution. We characterized their performance through phase behavior observation using fluorescence spectroscopy, Differential Calorimetry (DSC), and temperature-dependent viscosity study. Salt-induced gelation was carried out using a fluorescence anisotropy study. The results demonstrate that the presence of alkali metal salts can enhance the formation of the NaDC gels, whereas the increase in temperature could cause the breakage of the hydrogen bonds and weaken the NaDC gels. The formation of hydrogels and the behavior of the sol–gel transformation of the sample may be obtained by finely modulating the concentrations of the alkali metal chlorides. Moreover, the addition of higher salt concentration (MCl) can lead to lower viscosity due to the formation of a mixture of gel and precipitates. Hence, the mechanical strength of the gels decreases. 1,6-diphenylhexatriene (DPH) was used to monitor the changes in salt-induced NaDC BS. We also observed that the salt concentration required to induce the precipitation process depends on the size of the cation. It follows an order: Li+ > Na+ > K+ > Rb+ > Cs+. Further, the dynamic light scattering (DLS) results show the presence of heterogeneity present in BSs aggregated medium.
References:
1. Y. Zhang, et.al., RSC Adv.,2014, 4, 62262–62271
3. J. Swain, et.al., Photochem. Photobiol. Sci.,2019,18, 2773-2781