Accurate and reliable surface-enhanced Raman spectroscopy assay for early detection of SARS-CoV-2 RNA with exceptional sensitivity

Hend Awad; Tarek A El-Brolossy; Tamer Abdallah; Ahmed Osman; Sohair Negm; Ossama I Mansour; Samia A Girgis; Hala M Hafez; Ali M Zaki; Hassan Talaat

doi:10.1016/j.saa.2024.124184

Accurate and reliable surface-enhanced Raman spectroscopy assay for early detection of SARS-CoV-2 RNA with exceptional sensitivity

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Mar 26:315:124184. doi: 10.1016/j.saa.2024.124184. Online ahead of print.

Authors

Affiliations

¹ Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
² Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt. Electronic address: elbrolosyta@gmail.com.
³ Institute of Basic and Applied Science - Egpt-Japan University of Science and Technology (E-JUST), Egypt.
⁴ Department of Physics and Mathematics, Banha University, Banha, Egypt.
⁵ Faculty of Medicine, Ain Shams University, Cairo, Egypt.

PMID: 38608556
DOI: 10.1016/j.saa.2024.124184

Abstract

This research proposes a highly sensitive and simple surface-enhanced Raman spectroscopy (SERS) assay for the detection of SARS-CoV-2 RNA using suitably designed probes specific for RdRp and N viral genes attached to a Raman marker. The sensitivity of the assay was optimized through precise adjustments to the conditions of immobilization and hybridization processes of the target RNA, including modifications to factors such as time and temperature. The assay achieved a remarkable sensitivity down to 58.39 copies/mL, comparable to or lower than the sensitivities reported for commercial fluorescent polymerase chain reaction (PCR) based methods. It has good selectivity in discriminating SARS-CoV-2 RNA against other respiratory viruses, respiratory syncytial virus (RSV), and influenza A virus. The reliability of the assay was validated by testing 24 clinical samples, including 12 positive samples with varying cycle threshold (Ct) values and 12 negative samples previously tested using real-time PCR. The assay consistently predicted true results that were in line with the PCR results for all samples. Furthermore, the assay demonstrated a notable limit of detection (LOD) of Ct (38 for RdRp gene and 37.5 for N-gene), indicating its capability to detect low concentrations of the target analyte and potentially facilitating early detection of the pathogen.

Keywords: COVID-19; Early detection; RNA hybridization; SARS-CoV-2; SERS assay.