In Situ Surface-Enhanced Raman Scattering Detection of a SARS-CoV-2 Biomarker Using Flexible and Transparent Polydimethylsiloxane Films with Embedded Au Nanoplates

Abstract

Coronavirus disease 2019 (COVID-19) remains an ongoing issue worldwide and continues to disrupt daily life. Transmission of infection primarily occurs through secretions when in contact with infected individuals, but more recent evidence has shown that fomites are also a source of virus transmission, especially in cold-chain logistics. Traditional nucleic acid testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contamination in cold-chain logistics is time-consuming and inaccurate because of the multiplex sampling sites. Surface-enhanced Raman spectroscopy (SERS) provides a rapid, sensitive, and label-free detection route for various molecules, including viruses, through the identification of the characteristic peaks of their outer membrane proteins. In this study, we embedded arbitrarily orientated gold nanoplates (Au NPLs) in polydimethylsiloxane (PDMS) elastomer and used it as biosensor for the ultrasensitive detection of the SARS-CoV-2 spike protein in cold-chain logistics. This transparent and flexible substrate can be wrapped onto arbitrary surfaces and permits light penetration into the underlying contact surface, enabling in situ and point-of-care SERS diagnostics. The developed assay displayed high reproducibility (8.7%) and a low detection limit of 6.8 × 10–9 g mL–1, indicating its potential to serve as a promising approach with increased accuracy and sensitivity for the detection of the S protein.

SARS-CoV-2 proteins monitored by long-range surface plasmon field-enhanced Raman scattering with hybrid bowtie nanoaperture arrays and nanocavities

“…45 Notably, the LOD of this assay was considerably superior to that of the commonly used polymerase chain reaction-based technique and some other previously reported label-free SERS-based detection methods. [46][47][48] Even though the LOD of our method cannot compare with that of some labeled SERS methods and some other optical, electrochemical, and field-effect transistor sensors, [49][50][51][52][53] our assay takes ∼30 min to complete without any sample pretreatment. Thus, our work stands out for its rapid detection speed, noninvasiveness, and nonautofluorescence interference and provides a solid platform for protein testing.…”

Recent Advances in Molecular and Immunological Diagnostic Platform for Virus Detection: A Review

“…On the other hand, the surface-enhanced Raman scattering (SERS) technique has been extensively adopted for virus detection, owing to its ultrahigh sensitivity and label-free detection. As a potent analytical technique for diagnostic investigations, many researchers have adopted SERS for the detection of various viruses such as SARS-CoV-2 [ 30 ], influenza viruses A and B [ 31 ], rotavirus [ 32 ], and hepatitis C virus [ 33 ]. Therefore, several studies have suggested that combining SERS with LFA can improve assay sensitivity.…”

Surface enhanced Raman spectroscopy based analysis of SARS-CoV-2 spike protein binding to ACE2 receptor

“…This technique has the advantage to be used non-invasively, label-free and can enable a fast analysis. Experiments with SERS already revealed that an analysis and detection of the SARS-CoV-2 virus and other variants is possible [8][9][15][16][17][18].…”