Antibacterial evaluation of cotton textile treated by trialkoxysilane compounds with antimicrobial moiety

Abstract

Compounds based upon aldehyde functionalities or long chain quaternary ammonium functionalities constitute two major classes of antimicrobial materials. The antibacterial activities of these two classes of compounds were evaluated in the unbound (free compound) aqueous suspension and in the bound surface-treated cotton textile against E. coli. After a one hour incubation, the minimum lethal concentration of AEM 5700, a commercially available quaternary ammonium functional silane from Aegis Environments, was found to be 84 μg/g in the deionized water. The salinity of the test media significantly affected the antibacterial activity of AEM 5700 free compound. The minimum lethal concentration was increased to 8000 μg/g in the artificial seawater. Inactivation against E. coli of either free butyraldehyde or undecanylaldehyde functional triethoxysilylane in the deionized water was not observed. Cotton textile treated with various concentrations of AEM 5700 showed a two-stage antibacterial behavior when immersed in the deionized water. The higher activity in the first stage was due to the combined action of the leachate and the surface-bound AEM 5700, whereas the activity in the second-stage was caused by the contact between the surface-bound AEM 5700 and E. coli. This analysis was confirmed when the AEM 5700 treated cotton textile was tested in the artificial seawater. The leachate in the artificial seawater had no activity. The first-stage antibacterial behavior was not observed. Only the contact between the surface-bound AEM 5700 and E. coli contributed to about a one log reduction plateau with time. For cotton textile treated by either of the examined trialkoxysilylaldehyde compounds, inactivation against E. coli was not found.

Effect of water-aging on the antimicrobial activities of an ORMOSIL-containing orthodontic acrylic resin

“…The result is supportive of a predominant contact-killing mechanism for the QAMS-containing orthodontic acrylic resin. Bromophenol blue assay is a colorimetric method that has been widely used in the textile industry for detecting leached quaternary ammonium salts from antimicrobial fabrics [38]. Degradation of acrylic resin caused by water-aging over time was believed to accelerate leaching of compounds from the polymer network [39].…”

An ORMOSIL-Containing Orthodontic Acrylic Resin with Concomitant Improvements in Antimicrobial and Fracture Toughness Properties

“…Although leaching of quaternary ammonium species was also detected by the bromophenol blue assay, this only occurred when a high concentration of QAMS (6 wt%) was incorporated in the acrylic. Moreover, recent studies have shown that quaternary ammonium silanes (SIQAC) that leached out of substrates had no residual antimicrobial activity [51] , due to association phenomena in aqueous media, such as micellization, formation of ion-pairs and small aggregates [52] . These deactivation processes are significantly enhanced in the presence of NaCl [51] .…”

Optimizing resin-dentin bond stability using a bioactive adhesive with concomitant antibacterial properties and anti-proteolytic activities

“…Hence, incompletely co-polymerized QAMS within the polymer matrix would be expected to be released after aging in water or saliva. The bromophenol blue assay, commonly used in the textile industry for detecting leached quaternary ammonium salts from antimicrobial fabrics [44], was used to monitor the amount of quaternary ammonium moieties released from the QAMS-containing experimental adhesives. Results from the present study demonstrated continuous release of unreacted quaternary ammonium moieties from QAMS-containing resin disks into water during the first 30 days.…”