Microbial Growth Inhibition of Silver-Chitosan (AgNP-CS) Solution Technology Synthesized using Muntingia calabura L. as Silver Bio-reductant and Diadema setosum (Long-spined Sea Urchin) as Chitosan Novel Raw Materia

Abstract

Pathogenic microbes become resistant to antibiotics and pose health threats to humankind. This
led the urgent need for the global healthcare systems to search for novel strategies to combat these infectious
pathogens. Thus, this study aims to develop an antimicrobial nanocomposite solution using novel chitosan
(CS) material from Diadema setosum (Long-spined sea urchin) and silver nanoparticles (AgNPs)
synthesized using aqueous leaf extract Muntingia calabura L. (Aratiles). The chitosan was derived through
decolorization, deproteinization, demineralization, and deacetylation and was validated through Fourier
Transform Infrared Spectroscopy (FT-IR). While, the synthesized AgNP was initially confirmed by dark
brown color and validated using UV Visible Spectroscopy (UV-Vis) and Scanning Electron Microscopy
with Energy Dispersive X-Ray (SEM-EDX). Moreover, five treatments were prepared: T1(25% AgNP+75%
CS), T2 (50% AgNP+50% CS), T3 (75% AgNP+25% CS), T4 (100% AgNP), and T5 (100% CS) along
with Rifampicin as control and were tested for antimicrobial capacity against Escherichia coli
(BIOTECH1634), Staphylococcus aureus (BIOTECH 1582), Serratia marcescens (BIOTECH 1748),
Enterococcus faecalis (BIOTECH 10348), and Candida tropicalis (BIOTECH 2085). Results showed that
the chitosan has similar FT-IR profile with the standard establishing major functional groups like amino
(1632.25cm-1) and hydroxyl (3400.09 cm-1) with 36.09% degree of acetylation and 90% solubility. The
AgNPs had an absorbance of 404nm containing spherical structure in 62-91nm. Moreover, disc diffusion
assay results showed that all the treatments of the AgNP and CS had inhibited microbial growth. It was
found that Treatment 3 containing 75% AgNP and 25% CS had the largest zone of inhibition (ZOI) in test
pathogens except in S. aureus, being the most sensitive to the control. This study implies that AgNP-CS
solution has promising synergized microbial growth inhibition.