Minimized virus binding for tests of barrier materials

Abstract

Viruses are used to test the barrier properties of materials. Binding of virus particles during passage through holes in the material may yield misleading test results. The choices of challenge virus and suspending medium may be important for minimizing confounding effects that might arise from such binding. In this study, different surrogate viruses, as well as different support media, were evaluated to determine optimal test parameters. Two membranes with high-binding properties (nitrocellulose and cationic polysulfone) were used as filters to compare binding activities of different surrogate challenge viruses (MS2, X174, T7, PRD1, and 6) in different media. The media consisted of buffered saline with surfactants, serum, or culture broth as additives. In addition, elution rates of viruses that bound to the membranes were determined. The results suggest that viruses can bind by hydrophobic and electrostatic interactions, with X174 displaying the lowest level of binding by either process. The nonionic detergents Triton X-100 and Tween 80 (0.1%) equally minimized hydrophobic interactions. Neither anionic nor cationic surfactants were as effective at nontoxic levels. Serum was effective at reducing both hydrophobic and electrostatic binding, with 2% being sufficient for eliminating binding under our test conditions. Thus, X174 remains the best choice as a surrogate virus to test barrier materials, and Triton X-100 (0.1%) remains a good choice for reducing hydrophobic binding. In addition, binding of viruses by barrier materials is unlikely to prevent passage of blood-borne pathogens.

Impact of Chemical and Structural Anisotropy on the Electrophoretic Mobility of Spherical Soft Multilayer Particles: The Case of Bacteriophage MS2

“…The information derived from the study reported here forms the basis for a quantitative description of the electrostatic and hydrodynamic features of isolated MS2 bacteriophage. Knowledge of these interfacial characteristics is of outmost relevance for understanding on a fundamental level the interfacial phenomena of practical importance that MS2 are involved in, such as transport through groundwater (47)(48)(49)(50)(51)(52), virus filtration through membranes (53)(54)(55), bioadhesion (53,(56)(57)(58)(59)(60)(61)(62), and virus aggregation (63,64).…”

Elution of viruses by ionic and nonionic surfactants

“…It is of interest to know whether the same concentrations of surfactants, in addition to preventing adsorption, can elute adsorbed viruses. The recovery of adsorbed virus by soaking in surfactant did not give satisfactory results (8).…”

“…Test methods to evaluate various barrier devices, such as condoms and gloves (6,9), use bacteriophages (e.g., X174 or PRD1) as challenge viruses and as surrogates for human viruses (10). One possible confounding factor in such laboratory tests is virus adsorption leading to removal of virus, particularly during passage through the barrier (8,10). The nonionic surfactants Triton X-100 and Tween 80 are used in such tests to control the surface tension of the challenge fluid (2,9,12) and are also known to prevent virus adsorption in some situations (3,4,15,17), including to the highly binding membranes Bio-Trace NT (nitrocellulose) and BioTrace HP (cationic polysulfone) (8).…”

“…One possible confounding factor in such laboratory tests is virus adsorption leading to removal of virus, particularly during passage through the barrier (8,10). The nonionic surfactants Triton X-100 and Tween 80 are used in such tests to control the surface tension of the challenge fluid (2,9,12) and are also known to prevent virus adsorption in some situations (3,4,15,17), including to the highly binding membranes Bio-Trace NT (nitrocellulose) and BioTrace HP (cationic polysulfone) (8). It is of interest to know whether the same concentrations of surfactants, in addition to preventing adsorption, can elute adsorbed viruses.…”

Methods for the recovery of a model virus from healthcare personal protective equipment

“…MS2 is a nonpathogenic, nonenveloped virus, and has been used extensively as a surrogate for nonenveloped pathogenic viruses of humans (Allwood et al 2003;Meschke and Sobsey 2003;Dawson et al 2005;Sickbert-Bennett et al 2005;Bae and Schwab 2008). MS2 has also been shown to have a higher binding potential for PPE materials than other viruses traditionally used as viral surrogates, such as FX174 (Lytle et al 1991;Lytle and Routson 1995), making it a conservative surrogate for studies of disruption of viral binding to PPE. These qualities suggest that MS2 may be a promising surrogate for evaluating methods for recovery of viruses from healthcare PPE.…”