Eco-friendly and Green Synthesis of Antibacterial Silver-Nanocomposite Hydrogels with Ultra-High Mechanical Properties

Abstract

Physically cross-linked hydrogels are typically prepared without the use of toxic chemicals. Owing to the reversible nature of their bonds, these hydrogels exhibit self-healing ability, fatigue resistance, and enhanced toughness, making them highly attractive for biomedical applications. However, their generally poor mechanical properties often limit their practical utility. To address these challenges, the fabrication of physically cross-linked hydrogels with superior mechanical performance through eco-friendly, facile, and cost-effective methods without employing any toxic chemicals is of considerable interest. In this study, fully physically cross-linked double-network hydrogels with ultra-high mechanical properties were successfully prepared using a simple and environmentally friendly approach. The hydrogels were based on poly (vinyl alcohol) (PVA), agar, and tannic acid (TA), without the use of any toxic reagents. Additionally, a silver nanocomposite hydrogel fabricated by immersing the prepared hydrogel in an aqueous solution of silver nitrate (AgNO₃). The optimized PVA/Agar/TA double-network hydrogel exhibited outstanding mechanical properties, including a high tensile strength of 9.66 MPa and a superior fracture toughness of 16.51 MJ/m³. These values further increased to 12 MPa and 19.5 MJ/m³, respectively, for the PVA/Agar/TA/Ag nanocomposite hydrogel. Moreover, due to the reversible multiple hydrogen bonds within the network structures, the hydrogels demonstrated excellent self-recovery behavior and remarkable anti-fatigue performance. The prepared hydrogels exhibited notable antioxidant activity and excellent biocompatibility. The incorporation of silver nanoparticles (Ag-nanoparticles) further enhanced their antibacterial properties. Moreover, the presence of Ag-nanoparticles imparted electrical conductivity to the corresponding hydrogel.Consequently, these multifunctional hydrogels are promising candidates for various biomedical applications.

Graphical Abstract