Work

Optical label-free detection of SARS-CoV-2: investigating platform spectroscopic properties for oligonucleotide targeting

Year: 2025

Type: article

Abstract: We characterized a DNA/gold interface designed for the detection of the SARS-CoV-2 RNA-dependent RNA polymerase/Helicase (RdRp/Hel) sequence. Using broadband spectroscopic ellipsometry (SE) and a difference spectra approach, we monitored molecular modifications at the interface, from probe sequence deposition to the insertion of a molecular spacer and subsequent hybridization with the target. The UV region revealed the characteristic DNA absorption peak around 260 nm, while changes in δΔ in the NIR correlated with increased optical thickness following each deposition step. The optical response was analyzed as a function of target concentration, and the binding affinity curve, derived from δΔ values at 800 nm, was fitted using a first-order Langmuir model, yielding a dissociation constant K D = (70 ± 10) nM, consistent with literature values. Selectivity studies demonstrated that the interface effectively discriminates the SARS-CoV-2 sequence from the SARS-CoV HKU variant, even in a crowded environment. A complementary platform targeting the SARS-CoV HKU sequence confirmed selective detection of HKU over SARS-CoV-2. These findings highlight the potential for parallel detection of different viral sequences.

Source: European Biophysics Journal

DOI: 10.1007/s00249-025-01787-3

Authors: Silvia Maria Cristina Rotondi, Paolo Canepa, Silvia Dante, Maurizio Canepa, Ornella Cavalleri

Institutions: University of Genoa, Italian Institute of Technology

Language: English

Topic: Advanced biosensing and bioanalysis techniques

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $2,490

Funders: Dipartimenti di Eccellenza, Università degli Studi di Genova