Personal protective equipment (PPE), like facemasks and gowns, is generally made of polymers. But not much attention has typically been given to the selection of polymers used, beyond their physical properties. Andy Pye reviews some of the work being conducted in this innovative area.
Researchers from the University of Nottingham, EMD Millipore, and the Philipps University of Marburg have developed a high-throughput approach for analysing the interactions between materials and virus-like particles. They report their method in the journal Biointerphases, “Polymer Microarrays Rapidly Identify Competitive Adsorbents of Virus-Like Particles.”
“We’ve been very interested in the fact that polymers can have effects on cells on their surface,” said co-author Morgan Alexander of the University of Nottingham. “We can get polymers which resist bacteria without designing any particularly clever or smart material with antibiotic in there. You just have to choose the right polymer, extending the thinking on viral binding.”
The group created microarrays of 300 different monomer compositions of polymers representing a wide variety of characteristics. They exposed the polymers to Lassa and rubella virus-like particles – particles with the same structure as their viral counterparts but without the infectious genomes activated – to see which materials were able to preferentially adsorb the particles.
“Knowing that different polymers bind and possibly inactivate virus to different degrees means we may be able to make recommendations. Should I use this existing glove material or that glove if I want the virus to bind to it and die and not fly into the air when I take the gloves off?” Alexander added.
Though this may seem like an obvious method for quickly screening large quantities of materials, the team’s interdisciplinary makeup makes them uniquely positioned to conduct such a study. The surface scientists have the capabilities to create large numbers of chemicals on microarrays, and the biologists have access to virus-like particles.
So far, the tests have only looked at virus-like particles of Lassa and rubella, but the group is hoping to acquire a grant to look at virus-like particles of SARS-CoV-2.
Once a handful of the best-performing materials have been determined, the next step of the project will be to use live viruses to evaluate the viral infectious lifetime on the materials, taking into account real-world environmental conditions, like humidity and temperature. With enough data, a molecular model can be built to describe the interactions.
“Strong binding and quick denaturing of a virus on a polymer would be great,” Alexander said. “It remains to be seen whether the effect is significantly large to make a real difference, but we need to look to find out.”
Additive manufacturing of PPE
Different additive manufacturing technologies have proven effective and useful in remote medicine and emergency or disaster situations and in relation to the continuous supply of personal protective equipment (PPE). One study from the University of Pecs in Hungary aims to give a detailed overview of 3D-printed PPE devices and provide practical information regarding the manufacturing and further design process, as well as describing the potential risks of using them.
Open-source models of a half-facemask, safety goggles, and a face-protecting shield are evaluated, considering production time, material usage and cost. Estimations have been performed with fused filament fabrication (FFF) and selective laser sintering (SLS) technology, highlighting the material characteristics of polylactic acid (PLA), polyamide, and a two-compound silicone.
Spectrophotometry measurements of transparent PMMA samples were performed to determine their functionality as goggles or face mask parts. All the tests were carried out before and after the tetra-acetyl-ethylene-diamine (TAED)-based disinfection process. The results show that disinfection has no significant effect on the mechanical and structural stability of these polymers, meaning that 3D-printed PPE is reusable.
Polymer additives can inactivate pathogens
Facemasks have been proven to be medicine’s best public health tool for preventing transmission of airborne pathogens. However, in situations with continuous exposure, lower quality and “do-it-yourself” face masks cannot provide adequate protection against pathogens, especially when mishandled. In addition, the use of multiple face masks each day places a strain on PPE supply and is not environmentally sustainable. Therefore, there is a significant clinical and commercial need for a reusable, pathogen-inactivating face mask.
A study at Case Western University Reserve proposed adding poly(dimethylaminohexadecyl methacrylate), aka q(PDMAEMA), to existing fabric networks to generate “contact-killing” face masks – effectively turning cotton, polypropylene, and polyester into pathogen-resistant materials. It was found that q(PDMAEMA)-integrated face masks were able to inactivate both Gram-positive and Gram-negative bacteria in liquid culture and aerosolized droplets. Furthermore, q(PDMAEMA) was electro-spun into homogeneous polymer fibres, which makes the polymer practical for low-cost, scaled-up production.
Modified polymers for PPE
A variety of textile composites have been developed to ensure that the PPE products used both in the workplace and in other settings are sufficiently comfortable. Such composites have been used in contoured footwear insoles and air-purifying half-masks. The demand for specialised non-woven products is also on the increase: polymer non-wovens have found many applications, including respiratory protective devices, which contain multilayer non-wovens produced by different methods. An extensive literature search covers the considerable research being conducted in surface modification by means of low-temperature plasma, nanostructures and biodegradable polymers. A popular method of modification of polymer materials is the electrostatic activation involving low-temperature atmospheric-pressure plasma, and in particular corona discharge.
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This was very informative blog..Thank you!