Synthesis of sericin‐conjugated silver nanoparticles and their potential antimicrobial activity

Abstract

Nanoparticles (NPs) are being recognized as antibacterial agents due to their rapidly increasing multidrug resistance in bacterial pathogens. Hence, there is an unmet need to identify the natural antibacterial agent. The present study aimed to evaluate the antibacterial activity of sericin-conjugated silver NPs synthesized by using sericin as a reducing and capping agent. Synthesized NPs were characterized by scanning electron microscope, nanolaser particle size analyzer (BT-90), Fouriertransform infrared analysis, and energy-dispersive X-ray. The biogenic NPs significantly inhibited the growth of Escherichia coli (12-15 mm zone of inhibition), Staphylococcus aureus (14.6-15.4 mm zone of inhibition), and Klebsiella pneumoniae (12.5-18 mm zone of inhibition). The stability of naturally synthesized NPs was examined at various temperatures (i.e., 4°C, 37°C, and 55°C) and pH (i.e., 3, 7, and 11). Temperature variability did not significantly affect the efficacy of NPs. However, NPs performed better at higher pH levels. This study suggested that the sericinbased silver NPs are not only effective against bacteria, but they also maintain the stability at different ranges of temperature and pH. We concluded that the sericinconjugated silver NPs possess the remarkable antibacterial potential, which suggests their large-scale use as a cheap and stable antimicrobial agent in the future. K E Y W O R D Santibacterial activity, nanoparticles, sericin, silver

Green synthesis of silk sericin-embedded silver nanoparticles and their antibacterial application against multidrug-resistant pathogens

“…Sericin served as the reductant of silver ion, the dispersant and stabilizer of the prepared sericin-silver nanoparticle composite [16]. Tahir et al (2020) evaluated the antibacterial activity of sericinconjugated silver NPs synthesized using sericin as a reducing and capping agent [13,17]. Aramwit et al [8] synthesized silk sericin (SS)-capped silver nanoparticles (AgNPs) under alkaline conditions (pH 11) using SS as a reducing and stabilizing agent instead of toxic chemicals.…”

Changes in Number and Antibacterial Activity of Silver Nanoparticles on the Surface of Suture Materials during Cyclic Freezing

“…In addition, sericin has cytocompatibility with mammalian cells and is able to retain AgNPs, as well as efficiently release them directly into the wound [ 55 ]. Moreover, sericin-conjugated AgNPs retain their high antibacterial activity against Escherichia coli (12–15 mm zone of inhibition), Staphylococcus aureus (14.6–15.4 mm zone of inhibition), and Klebsiella pneumoniae (12.5–18 mm zone of inhibition) in environments with different pH levels (3.0–11.0) and temperatures (4–55 °C), which allows them to be used as an antimicrobial agent [ 56 ]. The interaction of silver and sericin can occur due to the hydroxyl group (−OH) of tyrosine, which can manifest itself as a specific signal in FTIR-spectroscopy at 1640cm −1 [ 56 ], as well as by van der Waals interaction with stabilization of the structure of the [AgNP–protein] complex due to hydrophobic regions leading to an increase in the binding constant with increased temperature [ 51 ].…”

“…Moreover, sericin-conjugated AgNPs retain their high antibacterial activity against Escherichia coli (12–15 mm zone of inhibition), Staphylococcus aureus (14.6–15.4 mm zone of inhibition), and Klebsiella pneumoniae (12.5–18 mm zone of inhibition) in environments with different pH levels (3.0–11.0) and temperatures (4–55 °C), which allows them to be used as an antimicrobial agent [ 56 ]. The interaction of silver and sericin can occur due to the hydroxyl group (−OH) of tyrosine, which can manifest itself as a specific signal in FTIR-spectroscopy at 1640cm −1 [ 56 ], as well as by van der Waals interaction with stabilization of the structure of the [AgNP–protein] complex due to hydrophobic regions leading to an increase in the binding constant with increased temperature [ 51 ]. The formation of the [AgNP–protein] complex also provides additional energy transfer between amino acids (tyrosine, tryptophan, phenylalanine) and silver nanoparticles, which can play a role in the regeneration of silver ions during cyclic freezing/thawing of fibers with previously adsorbed nanoparticles.…”

Innovative biosynthesis of silver nanoparticles using yeast glucan nanopolymer and their potentiality as antibacterial composite

“…These reducing capabilities were reinforced via transforming βG to βG NPs, which could be proved by the lesser Ps of biosynthesized Ag NPs and their stabilization [27]. The βG NPs could stabilize Ag NPs, assumingly via the formation of triple‐helical structures capping the metals NPs [5], which was suggested to generate bio‐based nano‐molecules with minimum toxicity toward the human body [28–30]. The appeared deep brown color and the absorbance band at 425 nm are attributed to Ag NPs plasmon resonance, which authenticated the successful Ag NPs formation after reduction with βG NPs [16,31].…”

“…The comparable antibacterial potentialities of Ag NPs and βG–Ag NPs could indicate the dominant bactericidal activity of Ag NPs, either in plain form or in conjugation with βG NPs. The Ag NPs antibacterial action was affirmed from numerous studies, including its composites with biopolymers and proteins [28,30,32]. The bacterial inhibitory actions from plain Ag NPs and βG–Ag NPs composites were comparable with nonsignificant differences between them toward each individual strain, which advocate the application of βG–Ag NPs combination as reduced toxic agents with the same antimicrobial potentials [28,29,32].…”