Nanocomposites of Terbium Sulfide Nanoparticles with a Chitosan Capping Agent for Antibacterial Applications

Abstract

This study aims to investigate the effect of alkaline pH on the bottom-up synthesis of nanocomposites (NCs) containing terbium sulfide nanoparticles (Tb2S3 NPs), where chitosan (CS) was employed as a capping agent, along with evaluation of the antibacterial activity of these NCs. The NCs were characterized using spectroscopy (FESEM-EDX, Raman, FTIR, XRD, XPS, and DLS), zeta-potential, and TGA. The results of FE-SEM, XPS, Raman, and FTIR characterization support the formation of CS-Tb2S3 NPs. A pH variation from 9 to 11 during composite formation was shown to affect the size and composition of NCs. The antibacterial activity of CS-Tb2S3 NCs was studied by coating onto commercial contact lenses, where the best loading efficiency of NCs was 48%. The NCs prepared at pH 10 (without contact lenses) had greater antibacterial activity against Staphylococcus aureus, with a zone of inhibition diameter of 7.15 mm. The coating of NCs onto commercial contact lenses was less effective for inhibition of Staphylococcus aureus, in contrast with the greater activity observed for tetracycline. CS-Tb2S3 NCs offer promising antimicrobial properties that can be further optimized by control of the surface loading and accessibility of Tb2S3 NPs through further study of the role of the chitosan capping agent, since steric effects due to CS are likely to attenuate antimicrobial activity via reduced electron transfer in such nanocomposite systems.

Potential Biomedical Applications of Terbium-Based Nanoparticles (TbNPs): A Review on Recent Advancement

“…Chitosan functions as the capping agent and the steric effect it causes aids in reducing the antibacterial activity by facilitating electron transfer in the produced nanocomposite systems. 54 Tb is utilized in the synthesis of metal−organic frameworks to achieve potent antibacterial properties while also enabling the real-time detection of bacterial spores. Therefore, Yin Y et al investigated the usage of a Tb functionalized silver-driven metal−organic framework for its potent antibacterial activity against Bacillus subtilis and E. coli.…”

“…Nevertheless, Tb has demonstrated exceptional biocompatibility and minimal harm to neighboring cells when present at low doses. Several research has explored the possible utilization of Tb ions in biological and medical contexts, particularly in the fields of imaging and diagnosis. , Furthermore, because of the robust fluorescent characteristics of Tb, it is often employed as a biomolecule tracer. Tb is utilized in the identification of the Anthrax biomarker dipicolinic acid (DPA) .…”

“…These nanocomposites have been found to be highly successful in their ability to combat bacterial infections. Chitosan functions as the capping agent and the steric effect it causes aids in reducing the antibacterial activity by facilitating electron transfer in the produced nanocomposite systems . Tb is utilized in the synthesis of metal–organic frameworks to achieve potent antibacterial properties while also enabling the real-time detection of bacterial spores.…”