Green Synthesis of Controlled Shape Silver Nanostructures and Their Peroxidase, Catalytic Degradation, and Antibacterial Activity

Abstract

Nanoparticles with unique shapes have garnered significant interest due to their enhanced surface area-to-volume ratio, leading to improved potential compared to their spherical counterparts. The present study focuses on a biological approach to producing different silver nanostructures employing Moringa oleifera leaf extract. Phytoextract provides metabolites, serving as reducing and stabilizing agents in the reaction. Two different silver nanostructures, dendritic (AgNDs) and spherical (AgNPs), were successfully formed by adjusting the phytoextract concentration with and without copper ions in the reaction system, resulting in particle sizes of ~300 ± 30 nm (AgNDs) and ~100 ± 30 nm (AgNPs). These nanostructures were characterized by several techniques to ascertain their physicochemical properties; the surface was distinguished by functional groups related to polyphenols due to plant extract that led to critical controlling of the shape of nanoparticles. Nanostructures performance was assessed in terms of peroxidase-like activity, catalytic behavior for dye degradation, and antibacterial activity. Spectroscopic analysis revealed that AgNDs demonstrated significantly higher peroxidase activity compared to AgNPs when evaluated using chromogenic reagent 3,3′,5,5′-tetramethylbenzidine. Furthermore, AgNDs exhibited enhanced catalytic degradation activities, achieving degradation percentages of 92.2% and 91.0% for methyl orange and methylene blue dyes, respectively, compared to 66.6% and 58.0% for AgNPs. Additionally, AgNDs exhibited superior antibacterial properties against Gram-negative E. coli compared to Gram-positive S. aureus, as evidenced by the calculated zone of inhibition. These findings highlight the potential of the green synthesis method in generating novel nanoparticle morphologies, such as dendritic shape, compared with the traditionally synthesized spherical shape of silver nanostructures. The synthesis of such unique nanostructures holds promise for various applications and further investigations in diverse sectors, including chemical and biomedical fields.

Biosynthesis of Functional Silver Nanoparticles Using Callus and Hairy Root Cultures of Aristolochia manshuriensis

“…The results unequivocally prove that aspects of A. manshuriensis culture extracts efficiently reduced silver ions to Ag 0 under the given reaction conditions. The XRD results affirm that the nanocrystals produced from A. manshuriensis are akin to previously described biologically synthesized AgNPs [ 59 , 60 ].…”

“…The results unequivocally prove that aspects of A. manshuriensis culture extracts efficiently reduced silver ions to Ag 0 under the given reaction conditions. The XRD results affirm that the nanocrystals produced from A. manshuriensis are akin to previously described biologically synthesized AgNPs [59,60]. Further analysis of AgNPs was conducted using FTIR to pinpoint the biomolecules that play a fundamental role in the reduction and stabilization of silver ions (Figure 3).…”

Enhanced Antioxidant Activity and Reduced Cytotoxicity of Silver Nanoparticles Stabilized by Different Humic Materials

“…In addition to the obvious environmental advantages, “green synthesis” can also provide more pronounced biological properties (antioxidant, antitumor activity, etc. ), which is due to the intrinsic properties of natural matrices [ 51 , 52 ]. In other words, the “green synthesis” of AgNPs can be particularly useful for creating biomedical nanomaterials with improved properties and high potential for use in medical applications.…”

Confining the Growth of AgNPs onto Epigallocatechin Gallate-Decorated Zein Nanoparticles for Constructing Potent Protein-Based Antibacterial Nanocomposites

“…Naturally occurring macromolecules, such as polyphenols and proteins, are extensively used as building units of nanoarchitecture. − Nature provides almost all the preferences for its creation, including favorable biocompatibility and biodegradability, high abundance, and ease of modification. Due to the presence of similar mussel-like structural units as dopamine, plant-derived polyphenols [such as epigallocatechin gallate (EGCG), epigallocatechin, and tannic acid] also exhibit similarly diverse physical and chemical properties, including universal coating and metal ion complexation. ,, Recently, the green synthesis of AgNPs was increasingly reported using natural-derived polyphenols as reducing agents, while the AgNPs tend to grow randomly, agglomerate, and entangle with the polyphenols, which leads to their poor specific surface area and properties; as a result, the antibacterial activities were compromised. − Therefore, one of the main obstacles to engineer AgNPs using green chemistry principles is how to confine the growth, avoid aggregation and oxidation, and achieve robust antibacterial performance at relatively low doses. A facile and straightforward strategy to enhance the activity of AgNPs is in situ growth on biomacromolecules as supporting materials to direct the nucleation and growth of AgNPs .…”