Facile Synthesis of Bioactive Silver Nanocomposite Hydrogels with Electro-Conductive and Wound-Healing Properties

Bioactive metal and metal oxide-based nanocomposite hydrogels exhibit significant antibacterial properties by interacting with microbial DNA and preventing bacterial replication. They offer potential applications as coating materials for human or animal skin injuries to prevent microbial growth and promote healing. In this study, silver nanoparticles (AgNPs) were synthesized using a chemical reduction method and incorporated into a polymer network to fabricate silver nanocomposite hydrogels (AgNCHGs) through a simple free radical polymerization method. N-isopropylacrylamide (NIPA), which has lower critical solution temperature (LCST) at about body temperature, or acrylamide (AAm) was used as the main monomer, while one or more ionic co-monomers, such as acrylic acid (AAc) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), were incorporated to obtain AgNCHGs. AgNPs were introduced into the hydrogel network via three different approaches. In the first method, the synthesized hydrogel was immersed in a silver nitrate (AgNO₃) solution and reduced in situ using sodium borohydride (NaBH₄) as a reducing agent. The second method involved mixing AgNO₃ with gel precursors before reduction with NaBH₄ to form AgNPs within the hydrogel. The final approach synthesized the AgNCHGs directly in a dispersion of pre-fabricated AgNPs. The incorporation of AgNPs in different AgNCHGs was confirmed through various characterization techniques. Varying temperature and pH conditions can trigger the release of bioactive AgNPs from the hydrogels. Furthermore, the antimicrobial and wound-healing properties of the AgNCHGs were evaluated against bacteria and fungi, demonstrating their potential in biomedical applications. In addition, AgNCHGs exhibit excellent electrical conductivity. The electrical conductivity of the hydrogels can be finely tuned by adjusting the concentration of AgNPs, making these materials promising candidates for energy, sensor, and stretchable electronics applications. This study presents facile synthesis methods of AgNCHGs, which integrate bioactivity, wound healing, and electrical conductivity in the same matrix, addressing a significant challenge in designing multifunctional hydrogels for next-generation technologies.