Smart soft supramolecular hybrid hydrogels modulated by Zn2+/Ag NPs with unique multifunctional properties and applications

Abstract

The development of low molecular weight molecule-mediated biocompatible soft supramolecular hydrogels, considered to be next-generation materials for biomedical applications, is a challenging task. In this context, the present work reports the synthesis of the hybrid hydrogel (CISZ2H) comprising ternary nanohybrids (Zn²⁺–Ag NPs@β-FeOOH@5′-CMP), consisting of greener components as a building block with hydrophobic tail (containing Zn²⁺ ions, Ag NPs, and β-FeOOH) and hydrophilic head (5′-cytidine monophosphate (5′-CMP)). The presence of Zn²⁺ ions and Ag NPs in the nanohybrids introduces new coordination sites and induces the puckering of the ribose sugar in 5′-CMP to generate the solid-like network in the self-assembly via micellar formation involving building blocks. Extensive cross-linking among organic and inorganic moieties provide these hydrogels with unique physicochemical features of improved mechanical strength (∼71 000 Pa), large water retention capability (600%), self-healing, and injectability as arrived at by thixotropic measurements, low toxicity, and enhanced drug/dye loading capabilities. Thus, the co-doped Zn²⁺ ions and Ag NPs in CISZ2H impart it with enhanced mechanical stability, shear thinning, external stimuli-responsiveness (pH and temperature), sustained slow drug release, surface enhanced Raman scattering (SERS) activity, and antibacterial features, thereby making this hydrogel safer for drug delivery, wound healing, sensing, and tissue engineering. The excellent features of the as-synthesized hydrogels make it a smart soft material for advanced applications with enormous future potential.