Gemini-Mediated Self-Disinfecting Surfaces to Address Contact Transmission of Infectious Diseases

According to both the Center for Disease Control (CDC) and the World Health Organization (WHO), contact-transmission (contact between host tissues and a contaminated surface) is the primary transmission route of infectious diseases worldwide. Usually this is mitigated by adherence to a schedule of repeated regular sanitization, yet this approach is inherently limited by sanitization frequency; conventional disinfectants/methods are only germicidal during the period of application, and surfaces are easily re-contaminated in the interim between cleanings. One solution to this problem is to use agents/coatings that impart self-disinfecting properties onto the existing surfaces such that they display sustained virucidal/antimicrobial properties against pathogens that settle upon them. Quaternary-ammonium organosilicon compounds are ideal candidates to achieve this; cationic surfactants are safe and well-established surface disinfectants while organosilanes are used broadly to form durable coatings with altered surface properties on many different materials. Despite their potential to circumvent disadvantages of traditional disinfection methods, extant commercially available quaternary-ammonium silanes do not display comparable efficacy to standard surface disinfectants, nor have their respective coatings been demonstrated to meet the Environmental Protection Agency’s guidelines for residual/extended efficacy. Inspired by powerful surface activity of double-headed “gemini” surfactants, here we present gemini-diquaternary (GQ) silanes with robust residual germicidal efficacy on various surfaces by incorporating a second cationic “head” to the structure of an conventional mono-quaternary-ammonium silane. Aqueous solutions of GQs were tested in suspension- and surface-antimicrobial assays against an array of pathogens, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). GQ performance was benchmarked against the common disinfectants, ethanol, hydrogen peroxide and hypochlorite, as well as against a common antimicrobial mono-quaternary (MQ) silane. Solutions of GQ silanes were efficacious when used for immediate disinfection, showing comparable activity to common disinfectants (>106 fold reduction in 15 seconds). Additionally GQ solutions were demonstrated to impart durable self-disinfecting properties to a variety of porous and nonporous surfaces, efficacious after repeated cycles of abrasion and repeated contaminations, and with superior coating ability and activity (>108 higher activity) than that of the popular MQ silane. GQ solutions as surface treatments show great promise to overcome the limitations of traditional disinfectants in preventing the spread of infectious diseases.