Lectin-Coated Silver/Silver Chloride Nanoparticles in Combination with Gentamicin - A Strategy to Preserve Antibiotic Efficacy at Lower Doses Against Pathogenic Planktonic Bacteria

Sep 29, 2026

Rampant antibiotic overuse has driven the rise of antibiotic resistance, creating a need for antibacterial strategies that reduce reliance on conventional drugs and slow resistance development. Concanavalin A-coated silver/silver chloride nanoparticles (ConA/Ag/AgCl-NPs) are evaluated as an alternative that links metallic silver’s antimicrobial action with ConA’s ability to bind membrane carbohydrates and gentamicin. Results show altered plasmonic resonance and strong synergy, lowering MICs for planktonic Staphylococcus aureus and Pseudomonas aeruginosa, while gentamicin usage drops by over 90%. Killing kinetics confirm bactericidal effects, and biofilm reduction requires concentrations far above planktonic MICs.

LanguageEnglish

CategoryResearch & Report

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Pages11

Reading Time28 min

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Abstract

Introduction

This article is licensed under CC-BY 4.0 [http://pubs.acs.org/journal/acsodf](http://pubs.acs.org/journal/acsodf) Article Lectin-Coated Silver/Silver Chloride Nanoparticles in Combination with Gentamicin: A Strategy to Preserve Antibiotic Efficacy at Lower Doses Against Pathogenic Planktonic Bacteria Viviane Brito Andrade, Diógenes G. da S. Fernandes, Dnane Vieira Almeida, Geomar F. Cruz, Tamara Jarosi Handajevsky, Daiany A. Ribeiro, Claudener S. Teixeira, André Luis Coelho da Silva, Fernanda Dias da Silva, and Wanius Garcia* Cite This: ACS Omega 2025, 10, 58164−58174 Read Online | | | | | | | | --- | --- | --- | --- | --- | --- | | ACCESS | Metrics & More | | Article Recommendations | | *sı Supporting Information | ABSTRACT: The rampant overuse of antibiotics in recent decades has significantly contributed to the emergence of antibiotic resistance. This highlights the need for new antibacterial strategies to reduce dependence on traditional antibiotics and slow the development of resistance. Concanavalin A-coated silver/silver chloride nanoparticles (ConA/Ag/AgCl-NPs) offer a promising alternative, combining the antimicrobial activity of metallic silver with the ability of concanavalin A to interact with both membrane carbohydrates and antibiotic gentamicin. The aim of this study is to investigate the synergistic antibacterial activity of gentamicin combined with ConA/Ag/AgCl-NPs against pathogenic bacteria. Our results confirmed that gentamicin interacts with ConA/Ag/AgCl-NPs, altering their plasmonic resonance properties. The combination of gentamicin with ConA/Ag/AgCl-NPs significantly reduced the minimum inhibitory concentration (MIC) values of both, from 0.19 μg/ mL and 0.04 μg/mL to 0.02 μg/mL and 0.01 μg/mL, respectively, required to inhibit planktonic Staphylococcus aureus. Similarly, the MIC values required to inhibit planktonic Pseudomonas aeruginosa reduced from 0.39 μg/mL and 0.02 μg/mL to 0.02 μg/mL and 0.0012 μg/mL, respectively. In both cases, a reduction of more than 90% in the amount of gentamicin used was observed. These data demonstrate synergistic antibacterial activities, as revealed by the fractional inhibitory concentration indexes below 0.5. Additionally, a killing kinetic assay confirmed bactericidal effects of the combination against both strains tested. Conversely, for both strains, ConA/Ag/AgCl-NPs exhibited substantial reduction in biofilm formation only at a concentration at least 500-fold greater than the MIC values observed for planktonic cells. Therefore, the strategy presented here allows for significantly lower doses of gentamicin to achieve the same level of effectiveness against pathogenic planktonic bacteria. 1. INTRODUCTION Lectins, proteins known for their reversible binding to specific sugars, also exhibit antimicrobial properties.1,2 The first legume lectin reported was the Concanavalin A (ConA) isolated from the seeds of the jack bean (Canavalia ensiformis).3 ConA specifically targets and binds to mannose or glucose sugars on the cell surface through its carbohydrate recognition domain (CRD).4 A recent study demonstrated that gentamicin, an aminoglycoside antibiotic that inhibits bacterial protein synthesis, exhibits enhanced antibacterial activity against multidrug-resistant (MDR) Staphylococcus aureus and Escherichia coli when combined with ConA. However, no significant antibacterial activity was observed against MDR Pseudomonas aeruginosa with the same combination. The study also revealed an interaction between gentamicin and the lectin’s CRD.5 Several types of nanoparticles (NPs), including metal oxides, silver halides, and mesoporous silica NPs,6−11 possess intrinsic antibacterial properties. Additionally, they can serve as nanocarriers to deliver antibiotics or other therapeutic agents. The potential of silver-based NPs in biomedical applications stems from their multifaceted approach to combating bacteria. These NPs exhibit direct antibacte

FAQs

Why are new antibacterial strategies needed in the study?

Antibiotic overuse has contributed to the emergence of antibiotic resistance, requiring approaches that reduce dependence on traditional antibiotics and slow resistance development.

What is the role of ConA/Ag/AgCl-NPs when combined with gentamicin?

ConA/Ag/AgCl-NPs combine metallic silver’s antimicrobial activity with ConA’s ability to interact with membrane carbohydrates and gentamicin, enabling synergistic antibacterial effects.

How did the combination affect MIC values and antibiotic dose usage?

For planktonic Staphylococcus aureus and Pseudomonas aeruginosa, MIC values decreased substantially, and the required amount of gentamicin was reduced by more than 90% in both cases.

Sep 29, 2026

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