Spike- and nucleocapsid-based gold colloid assay toward the development of an adhesive bandage for rapid SARS-CoV-2 immune response detection and screening

Abstract Immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies are important biomarkers used for the diagnosis and screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in both symptomatic and asymptomatic individuals. These antibodies are highly specific to the spike (S) and nucleocapsid (N) proteins of the SARS-CoV-2 virus. This paper outlines the development steps of a novel hybrid (vertical-lateral-vertical) flow assay in the form of a finger-stick point-of-care device, similar to an adhesive bandage, designed for the timely detection and screening of IgM and IgG immune responses to SARS-CoV-2 infections. The assay, comprising a vertically stacked plasma/serum separation membrane, conjugate pad, and detection (readout) zone, utilizes gold nanoparticles (AuNPs) conjugated with SARS-CoV-2 S and N proteins to effectively capture IgM and IgG antibodies from a pinprick (~15 µL) of blood in just one step and provides results of no immune IgM−/IgG−, early immune IgM+/IgG−, active immune IgM+/IgG+ or immune IgM−/IgG+ in a short amount of time (minutes). The adhesive bandage-like construction is an example of the design of rapid, low-cost, disposable, and easy-to-use tests for large-scale detection and screening in households. Furthermore, the bandage can be easily adjusted and optimized to detect different viral infections as they arise by simply selecting appropriate antigens related to pandemics and outbreaks

Characterization of Arsenic Contamination on Rust from Ton Containers

The speciation and spatial distribution of arsenic on rusted steel surfaces affect both measurement and removal approaches. The chemistry of arsenic residing in the rust of ton containers that held the chemical warfare agents bis­(2-chloroethyl)­sulfide (sulfur mustard) and 2-chlorovinyldichloroarsine (Lewisite) is of particular interest, because while the agents have been decontaminated, residual arsenic could pose a health or environmental risk. The chemistry and distribution of arsenic in rust samples were probed using imaging secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX). Arsenic in the III and or V oxidation state is homogeneously distributed at the very topmost layer of the rust samples and is intimately associated with iron. Sputter depth profiling followed by SIMS and XPS shows As at a depth of several nanometers, in some cases in a reduced form. The SEM/EDX experiments show that As is present at a depth of several micrometers but is inhomogeneously distributed; most locations contained oxidized As at concentrations of a few percent; however, several locations showed very high concentrations of As in the zerovalent form. These results indicate that the rust material must be removed if the steel containers are to be cleared of arsenic