Synthesis of Silver Nanoparticle-Based Chitosan Nanocomposites Using Neowestiellopsis persica Strain A1387 and Characterization of Their Potential Antimicrobial Activity Against Oral Pathogen

Abstract

Today, overuse and unregulated application of antibiotics and antimicrobial agents have resulted in a substantial increase in drug-resistant pathogens. Therefore, there is a great need for innovative therapeutic methods that can replace ineffective antibiotics. Cyanobacteria are one of the most useful natural candidates in the biosynthesis of nanoparticles to face antibiotic resistance in pathogens. In this study, the antimicrobial effect of different concentrations of silver (AgNPs) nanoparticles based chitosan nanocomposites biosynthesized by <i>Neowestiellopsis persica </i>against oral pathogens was investigated. The NPs biosynthesis were characterized through UV-visible spectroscopy, scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR) and X-ray diffraction analysis (XRD). Results of UV-visible Spectroscopy showed that the amount of absorption increased significantly with increasing time. The SEM and TEM images depict the size of the nanocomposite to be 78.74 to 74.29 and 100 nm respectively and spherical in shape. According to the results of the FT-IR spectrum, the peaks located at a wave number less than 800 cm^-1 are related to the stretching vibration of metal-oxygen bonds in a crystal structure, where due to the presence of silver nanoparticles, these peaks can be related to the symmetric and asymmetric stretching vibration of Ag-O bonds. The results of XRD crystallography confirmed the success of the synthesis of microcoated silver nanoparticles by chitosan. The average crystal size of silver nanoparticles covered by chitosan was 17.6 nm. The antimicrobial efficacy of the biosynthesized AgNP nanocomposite showed that with the increase in the concentration of nanoparticles and nanoparticles coated with chitosan, the diameter of the growth halo increased significantly (<i>p</i> &#60; 0.05). Totally the results of this study confirmed that nanoparticle-based chitosan nanocomposites biosynthesized by cyanobacteria species can be converted into nanomedicine to meet future biomedical needs.