A Bifunctional Spray Coating Reduces Contamination on Surfaces by Repelling and Killing Pathogens.

Surface-mediated transmission of pathogens is a major concern with regard to the spread of infectious diseases. Current pathogen prevention methods on surfaces rely on the use of biocides, which aggravate the emergence of antimicrobial resistance and pose harmful health effects. In response, a bifunctional and substrate-independent spray coating is presented herein. The bifunctional coating relies on wrinkled polydimethylsiloxane microparticles, decorated with biocidal gold nanoparticles to induce a "repel and kill" effect against pathogens. Pathogen repellency is provided by the structural hierarchy of the microparticles and their surface chemistry, whereas the kill mechanism is achieved using functionalized gold nanoparticles embedded on the microparticles. Bacterial tests with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa reveal a 99.9% reduction in bacterial load on spray-coated surfaces, while antiviral tests with Phi6─a bacterial virus often used as a surrogate to SARS-CoV-2─demonstrate a 98% reduction in virus load on coated surfaces. The newly developed spray coating is versatile, easily applicable to various surfaces, and effective against various pathogens, making it suitable for reducing surface contamination in frequently touched, heavy traffic, and high-risk surfaces.

Polyurethane With Instant And Persistent Antimicrobial Efficacy Against Bacteria And SARSCoV- 2

Purpose/Objectives: Gram-negative bacteria including E. coli and P. aeruginosa can survive for months on dry hard surfaces, and SARS viruses can persist for days. These contaminated surfaces along with patients' damaged skin barriers, due to wounds or central line insertion sites, increase the risk healthcare-acquired infections (HAI) and subsequent serious complications. Furthermore, with increased frequency and duration of hospitalizations due to the current pandemic, the number of HAIs is on the rise. Currently there are no antimicrobial surfaces that provide both instant and long-lasting antimicrobial protection against a broad spectrum of infectious microbes. Liquid- or radiation-based disinfection techniques are kill microbes quickly, but their effect does not last long before needing reapplication. Antimicrobial surfaces based on heavy metals remain antimicrobial for long durations, but complete disinfection can take hours. In this work, we developed a new class of plant-inspired antimicrobial surfaces and wound dressings that incorporate plant secondary metabolites capable of rapid disinfection (> 4-log reduction) of common bacteria and viruses and maintain their efficacy over time (> 6 months). Methodology: We developed a method for stabilizing naturally antimicrobial essential oils components from plants such as, alpha terpineol (AT) and cinnamaldehyde (CMA), within a polyurethane polymer. Using a modified standard method for evaluating the performance of different nonporous solids (ISO 22196) and median tissue culture infection dose assay, these antimicrobial polyurethane coatings were tested and found to be effective in killing E. coli, P. aeruginosa, methicillin-resistant S. aureus (MRSA), and SARS-CoV-2. The durability of the coatings was tested by linear abrasion, UV and airflow exposure. Application methods such as spray coating and dip coating allow the coating to be applied to a variety of surfaces. Results: Polyurethane surfaces containing 35% AT content (PU-35%AT) showed a ∼5.8-log reduction in E. coli colony forming units per cm2 (CFU/cm2) in under 2 minutes, a shorter time than common commercial disinfectants. Additionally, when subjected to 8 consecutive rounds of inoculation the PU- 35%AT surface reduced the E. coli by >99.99% for all 8 rounds. We achieved a ∼5.8-log reduction of MRSA within 5 minutes on PU-60%AT. The PU-35%AT surfaces showed a 4.0-log reduction in SARS-CoV- 2 in 60 minutes. A PU-70%AT showed a 1.6-log reduction after 10 minutes and maintained virucidal capabilities after 2 weeks. PU+35%AT surfaces maintained a ∼5.3-log reduction in CFU/cm2 in MRSA and E. coli after 1000 abrasion cycles, 12 hours of UV exposure, 25 hours of exposure to -17°C, or 5 months of air flow. Lastly, to demonstrate the coating's real world functionality the PU+35%AT coating was successfully applied to a computer keyboard, cell phone screen protector and medical gauze. Conclusion/Significance: This work demonstrates a novel approach for fabricating a broad-spectrum antibacterial and antiviral polymer surface based on plant essential oil components. This antimicrobial polyurethane coating has not only rapid bactericidal and virucidal capabilities but maintains this efficacy over time. Additionally, the coating can be applied to a variety of surfaces including medical gauze to create wound dressings that significantly reduce bacterial burden and decrease chances of HAIs.

A Copper nanoparticles-based polymeric spray coating: Nanoshield against Sars-Cov-2.

Face masks are an effective protection tool to prevent bacterial and viral transmission. However, commercial face masks contain filters made of materials that are not capable of inactivating either SARS-CoV-2. In this regard, we report the development of an antiviral coating of polyurethane and Copper nanoparticles on a face mask filter fabricated with a spray technology that is capable of inactivating more than 99% of SARS-CoV-2 particles in 30 min of contact.

Monitoring and Optimisation of Ag Nanoparticle Spray-Coating on Textiles.

An automatic lab-scaled spray-coating machine was used to deposit Ag nanoparticles (AgNPs) on textile to create antibacterial fabric. The spray process was monitored for the dual purpose of (1) optimizing the process by maximizing silver deposition and minimizing fluid waste, thereby reducing suspension consumption and (2) assessing AgNPs release. Monitoring measurements were carried out at two locations: inside and outside the spray chamber (far field). We calculated the deposition efficiency (E), finding it to be enhanced by increasing the spray pressure from 1 to 1.5 bar, but to be lowered when the number of operating sprays was increased, demonstrating the multiple spray system to be less efficient than a single spray. Far-field AgNPs emission showed a particle concentration increase of less than 10% as compared to the background level. This finding suggests that under our experimental conditions, our spray-coating process is not a critical source of worker exposure.

Enhancement of Antiviral Effect of Plastic Film against SARS-CoV-2: Combining Nanomaterials and Nanopatterns with Scalability for Mass Manufacturing.

Direct contact with contaminated surfaces in frequently accessed areas is a confirmed transmission mode of SARS-CoV-2. To address this challenge, we have developed novel plastic films with enhanced effectiveness for deactivating the SARS-CoV-2 by means of nanomaterials combined with nanopatterns. Results prove that these functionalized films are able to deactivate SARS-CoV-2 by up to 2 orders of magnitude within the first hour compared to untreated films, thus reducing the likelihood of transmission. Nanopatterns can enhance the antiviral effectiveness by increasing the contact area between nanoparticles and virus. Significantly, the established process also considers the issue of scalability for mass manufacturing. A low-cost process for nanostructured antiviral films integrating ultrasonic atomization spray coating and thermal nanoimprinting lithography is proposed. A further in-depth investigation should consider the size, spacing, and shape of nanopillars, the type and concentration of nanoparticles, and the scale-up and integration of these processes with manufacturing for optimal antiviral effectiveness.