Biopolymer-Based Composite Hydrogels Embedding Small Silver Nanoparticles for Advanced Antimicrobial Applications: Experimental and Theoretical Insights

Abstract

In this work, we report a two-step methodology for the synthesis of small silver nanoparticles embedded into hydrogels based on chitosan (CS) and hydroxypropyl methylcellulose (HPMC) biopolymers. This method uses d-glucose as an external green reducing agent and purified water as a solvent, leading to an eco-friendly, cost-effective, and biocompatible process for the synthesis of silver nanocomposite hydrogels. Their characterization comprises ultraviolet-visible spectroscopy, Fourier-transform infrared spectra, differential scanning calorimetry, scanning electron microscopy with energy-dispersive spectroscopy, and transmission electron microscopy assays. Moreover, the structural stability of the hydrogels was investigated through sequential swelling–deswelling cycles. The nanomaterials showed good mechanical properties in terms of their structural stability and revealed prominent antibacterial properties due to the reduced-size particles that promote their use as new advanced antimicrobial agents, an advantage compared to conventional particles in aqueous suspension that lose stability and effectiveness. Finally, theoretical analyses provided insights into the possible interactions, charge transfer, and stabilization process of nanoclusters mediated by the high-electron-density groups belonging to CS and HPMC, revealing their unique structural properties in the preparation of nano-scaled materials.

Synthesis, Characterization, and Evaluation of Silver Nanoparticle-Loaded Carboxymethyl Chitosan with Sulfobetaine Methacrylate Hydrogel Nanocomposites for Biomedical Applications

“…Additionally, to assess the formation of AgNPs within the CMCS-SB hydrogel, SEM images at both lower and higher magnifications are presented ( Figure 4 c,d). The presence of AgNPs within the CMCS-SB hydrogel networks suggests that when Ag + ions on the surface of the swollen hydrogel are reduced by NaBH 4 , the resulting AgNPs increase the gel porosity, providing a pathway for the reducing agents to enter the bulk of the hydrogel and produce the AgNPs/CMCS-SB nanocomposite [ 48 , 49 ]. Furthermore, incorporating AgNPs into the CMCS-SB hydrogel apparently affects the average pore size, which is likely owing to the interaction of the functional groups with the metallic particles, displacing the water molecules and modifying the structural characteristics of the hydrogel.…”

Last Advances on Hydrogel Nanoparticles Composites in Medicine: An Overview with Focus on Gold Nanoparticles

“…In the last years, Ag NPs have been exploited in biomedical applications and beyond, [101] given their biocompatibility, optical properties, and antibacterial nature. [102] In HNCs, they have been mainly used to confine the antibacterial properties in specific regions, for wound healing applications, [56] for NPs stabilization without further functionalization [103] or, coupled with Au NPs, to modify the system plasmonic properties (more details on the peculiar optical response of these noble metal NPs are provided in the following section). [70] The Ag NPs can be designed in different shapes, by tuning the chemical synthesis.…”