Fabrication of morphologically modified strong supramolecular nanocomposite antibacterial hydrogels based on sodium deoxycholate with inverted optical activity and sustained release

摘要

Low Molecular Weight (LMWG) gelators are small molecules that form supramolecular self-assembly involving physical forces and are highly biocompatible. However, fragility of these physical gels restricts their applicability where gels of higher mechanical strength are required. Herein, we have developed two different types of 2-D carbon nanomaterials viz. graphene oxide (GO) and carbon nanosheet (CNS) embedded sodium deoxycholate (NaDC) hydrogels. XRD, scanning electron microscopy (SEM), rheology and CD studies suggest significant modification of morphological, mechanical, viscoelastic and optical properties of the nanocomposite gels which is ascribed to the presence of the 2D nanotemplates and participation of different surface functionalities of GO and CNS in the gelation process. The overall shear resistance of both the nanocomposite hydrogels upto a shear rate of 300 shears/s(-1) and above reveals tremendously improved mechanical stability with respect to the pure gels. The increased shear strength of the GO/NaDC and CNS/NaDC hydrogels is attributed to their 3-4 times broader and longer ribbon like structures in comparison to the fibrous structure of pure gels. The intact ribbon like morphology and greater entanglement impart 10 folds greater viscosity to GO-NaDC hydrogels as compared to better elasticity of CNS-NaDC hydrogels possessing broken ribbon edges. Most interestingly both GO and CNS influence the optical activity of the gels and presence of GO results in inversion of optical activity. The GO-NaDC gels are also found to demonstrate antibacterial activity against E. coli, and S. aureus. Thus, these extraordinarily modified mechanically strong gels have enhanced potential for use in tissue engineering, enantioselective and sustained drug delivery, topical antibiotics and other biomedical applications.