Quaternized Polydopamine Coatings for Anchoring Molecularly Dispersed Broad-Spectrum Antimicrobial Silver Salts

Abstract

Because of the broad-spectrum antimicrobial efficacy, silver-based coatings have emerged as the popular choice to apply over frequently touched surfaces for mitigating the spread of nosocomial infections. Despite the advancements through various coating strategies, clustering of the active component remains a bottleneck in achieving the molecular-scale dispersion of silver. To circumvent this, the current study takes advantage of the recent findings of quaternary ammonium moieties forming molecular complexes with silver salts that differ from the simple adduct between the individual components. Here we demonstrate the quaternization of oxidatively cross-linked polydopamine coatings over magnetite nanoparticles to anchor ionic silver at a molecular-scale dispersion. The silver-derivatized materials exhibit remarkable broad-spectrum antimicrobial properties against representative microbes like E. coli, S. aureus, and A. niger. Also, the study reveals the materials’ antibiofilm efficacy (∼80–90%) against both bacteria. Further recyclability studies have proven the sustained bactericidal properties up to five cycles. The surface derivatization strategy has then been extended to cover glass slips that have also shown the retention of the bactericidal properties even after wiping 20 times with artificial sweat. The biocompatibility of the materials has been ascertained with treated water against the mouse fibroblast and human embryonic kidney cell lines. The current study offers insights in developing coatings with molecular-scale dispersion of ionic silver to achieve broad-spectrum antimicrobial properties in an atom-economical and sustainable manner.

Fabrication and Facile Surface Derivatization of Poly(ε‐caprolactone)‐Based Wound Dressing Materials Imparting Anti‐Infective, Excessive Biofluid Drainage, and Easy‐to‐Peel Characteristics

“…The longer time required for the bactericidal activity against the gram‐positive bacteria is attributed to the thicker cell membrane consisting of a peptidoglycan layer, as reported in the literature. [ 37 ][ 41 ][ 46 ] It can be noted that a near‐complete bactericidal activity against E. coli and S. aureus with ES‐4h‐AgCl was realized in 40 and 60 min, respectively. It is also noteworthy that the silver ion leaching was in the range of 0.64–0.72 ppm (Table S3, Supporting Information).…”

“…After washing the unbound spermine with deionized water, the spermine‐immobilized ES fiber was added with 10 mL of an aqueous solution containing 15 µL of GTMAC and the reaction between the amine and epoxy groups was allowed to take place for 3 h. Finally, after rinsing with deionized water, the GTMAC‐immobilized ES fibers were sequentially treated with AgNO 3 and KCl as per the previous report to obtain the AgCl‐derivatized ES fiber. [ 46 ] Based on the initial alkaline hydrolysis duration, the AgCl‐derivatized ES fibers from the lineages of 2 and 4 h of hydrolysis were termed as ES‐2h‐AgCl and ES‐4h‐AgCl, respectively. With PCL‐coated CG samples, the alkaline hydrolysis was carried out for 2 h only, as the solution was found to turn turbid with longer hydrolysis duration, due to the partial release of the polymer into the supernatant.…”

“…[44,45] To enhance the broad-spectrum antimicrobial efficacy of quaternary ammonium moieties, our group has recently developed a strategy to disperse ionic silver in a molecularly dispersed fashion by exploiting the unique interaction between the two to form a molecular complex-like structure. [46] This strategy of accumulating ionic silver at the surface was demonstrated with a polydopamine coating over oxide supports like magnetite and silica glass. Such a combination was also shown to circumvent any de novo resistance development in the representative gram-positive and gram-negative bacteria.…”

Efficient biodiesel production from rice bran oil using magnetite immobilized-recombinant lipase from probiotic Bacillus licheniformis

“…38,39 After APTES functionalization, the core level N 1s signal corresponding to the amino group could be distinguished at ∼400.0 eV (ref. 34 and 40) alongside the characteristic signals from Fe 3 O 4 . Besides, the O 1s narrow scan showed additional features at slightly higher binding energy values, indicating the effective anchoring and crosslinking of alkoxy silane, resulting in the formation of Si–O–Si and Si–O–Fe bonds.…”

Edible Acid–Base Complexes of Caffeic Acid with Histidine and Arginine Exhibit Enhanced Antimicrobial and Antioxidant Characteristics

“…Following the literature procedure, the resazurin assay was employed to ascertain the antimicrobial activity of the CA–amino acid complexes against Escherichia coli and Staphylococcus aureus . , The studies were carried out in triplicate using the CA–amino acid complexes in a concentration range of 0.625 to 25 mM. The percentage reduction of resazurin to resorufin was estimated by measuring the fluorescence intensity of the product at 590 nm using an excitation wavelength of 530 nm (SpectraMax iD3 plate reader; Molecular Devices) and plugging in the values in the below-given formula. …”