Synthesis, Structural Characterization, and Antimicrobial Evaluation of Silver Nanoparticle-embedded Layered Double Hydroxides for Delivery in Polymeric Hydrogel Matrices

This study aimed to synthesize and characterize silver nanoparticle-embedded layered double hydroxides (Ag-LDH) nanohybrids for potential antimicrobial applications. The research also focused on identifying suitable polymeric hydrogel matrices for embedding the Ag-LDH nanohybrids.

Ag-LDH nanohybrids were synthesized and the resulting nanohybrids underwent comprehensive characterization using various techniques, including UV-Vis spectroscopy, FTIR spectroscopy, XRD, TGA, DSC, DTA, particle size analysis, zeta potential measurement, and transmission electron microscopy. The antimicrobial activity of the LDH, Ag-NPs, and Ag-LDH was evaluated against a panel of Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and a fungus (Candida albicans) using the agar diffusion method. Polymeric hydrogel matrices, including sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, Carbopol 940, polyvinyl alcohol, and chitosan, were prepared and characterized for their rheological properties using a viscometer.

Characterization techniques confirmed the successful synthesis and intercalation of Ag-NPs within the LDH structure. Antimicrobial studies demonstrated enhanced antibacterial and antifungal activities of the Ag-LDH nanohybrid compared to individual LDH and Ag-NPs. The inhibition zone diameters for Ag-LDH against S. aureus, B. subtilis, E. coli, P. aeruginosa, and C. albicans were 16 ± 0.4 mm, 21 ± 0.8 mm, 16.8 ± 0.7 mm, 19.1 ± 1.1 mm, and 21.3 ± 0.9 mm, respectively. Rheological profiling of the Ag-LDH embedded polymeric matrices revealed varying viscosity profiles, indicating different flow behaviors and potential suitability for various delivery approaches.

The study successfully synthesized, characterized, and demonstrated the enhanced antimicrobial activity of Ag-LDH nanohybrids. Polymeric hydrogel matrices suitable for embedding these nanohybrids were also identified and characterized. Further research, including preclinical studies, could lead to the development of a scalable Ag-LDH hybrid suitable for clinical practice.