Revealing the Significance of the Glycan Binding Property of Butea monosperma Seed Lectin for Enhancing the Antibiofilm Activity of Silver Nanoparticles against Uropathogenic Escherichia coli

Abstract

The incompetence of conventional antibiotics against bacteria residing in biofilms demands newer therapeutic intervention. In this study, we demonstrated that the interaction between silver nanoparticles (AgNPs) and Butea monosperma seed lectin (BMSL) forms efficient surface-functionalized AgNPs with excellent antibiofilm competency against uropathogenic Escherichia coli (UPEC). The minimum biofilm inhibitory concentration (MBIC) of AgNPs and the BMSL−AgNP conjugate (BAgNP) against UPEC was 75 and 9.37 μM, respectively. The eight-fold reduction in the MBIC of AgNPs was attributed to lectin functionalization. The chemical modification of serine amino acids affects the hemagglutination activity of BMSL but not its interaction with the AgNPs. At the same time, AgNPs surface-functionalized with modified BMSL display poor antibiofilm activity. Molecular docking studies revealed that BMSL binds to galactose with a free energy of −5.72 kcal/mol, whereas the serine residue-modified BMSL showed the lowest free energy values, suggesting incompetence for binding galactose. These results showcase that the sugar binding site of BMSL aids in the adhesion of AgNPs to the biofilm matrix and disturbs the formation of the biofilm, which was confirmed by light microscopy using crystal violet staining. At 37.5 μM, BAgNPs also have the capability to eradicate preformed biofilm. As a proof of concept, UPEC biofilm prevention and eradication were demonstrated on a urinary catheter. A scanning electron microscopy study showed that BAgNPs prevent bacterial colonization and thereby curtail biofilm growth. In addition to antibiofilm activity, BAgNPs exert antibacterial activity at 18.75 μM, which is four-fold lower than the MIC of AgNPs. A mechanistic study revealed that BAgNPs affect the integrity of the bacterial outer membrane and generate an imbalance in the antioxidant defense, which induces cell death. The results highlight that lectin functionalization can be extended to other nanoparticles and different antibiotics to enhance their efficacy against drug-resistant bacteria.

Insights into Shape-Based Silver Nanoparticles: A Weapon to Cope with Pathogenic Attacks

“…Microalgal-extracted exopolysaccharide-mediated AgNPs showed prominent antibacterial activity against S. aureus , E. coli , and antibiotic-resistant methicillin-resistant S. aureus . Some plant seed extracts such as Silybum marianum and Butea monosperm were employed to synthesize AgNPs, which later proved to have antimicrobial and anticancer activity. Kenaf seed-mediated AgNPs exhibit potent activity against E. coli and S. aureus , which increases synergistically with the combination of ampicillin .…”

Antibacterial and antibiofilm potential of silver nanoparticles against antibiotic-sensitive and multidrug-resistant Pseudomonas aeruginosa strains

“…Some studies suggest that the main mechanism of biofilm destruction occurs through the binding of AgNPs in the exopolysaccharide matrix, disrupting the biofilm structure by recognizing the peptidoglycan structure present in bacterial membranes, causing physical damage, ion release, ROS production, leading to oxidative stress, and DNA damage (Fig. 2) [88,89]. When bacteria is treated with AgNPs, morphological changes are revealed in biofilm's architecture, such as uneven cell surface, suggesting cell lysis [70], relevant morphological damages in the cell wall, membrane corrugation damage, changes in membrane polarization and/or permeability [90], and distinct EPS-matrix formation surrounding the bacterial strains [91].…”

Shrimp lectin (Md-Lec) conjugated copper sulfide nanoparticles enhance the elimination of aquatic pathogens in infected Nile tilapia (Oreochromis niloticus)

“…For example, Butea monosperma lectin functionalized AgNPs were better than AgNPs in inhibiting the biolms formed by E. coli. 10 Parkia platycephala seed lectin enhances the antibiotic activity of gentamicin against the multi-drug resistant E. coli and S. aureus. 11 Lectins are glycoproteins that possess one or more Carbohydrate Recognition Domains (CRD) which can reversibly and specically bind to certain sugar molecules.…”