Lithographic SERS Aptasensor for Ultrasensitive Detection of SARS-CoV-2 in Biological Fluids

Abstract

In this paper, we propose a technology for the rapid and sensitive detection of the whole viral particles of SARS-CoV-2 using double-labeled DNA aptamers as recognition elements together with the SERS method for detecting the optical response. We report on the development of a SERS-aptasensor based on a reproducible lithographic SERS substrate, featuring the combination of high speed, specificity, and ultrasensitive quantitative detection of SARS-CoV-2 virions. The sensor makes it possible to identify SARS-CoV-2 in very low concentrations (the limit of detection was 100 copies/mL), demonstrating a sensitivity level comparable to the existing diagnostic golden standard—the reverse transcription polymerase chain reaction.

Multiplex Lithographic SERS Aptasensor for Detection of Several Respiratory Viruses in One Pot

“…Resonant Raman compounds, i.e., cyanine three (Cy3) or tetramethylrodamine (TAMRA) fluorescent dyes, were introduced at the 5 ends of the aptamers (Figure 2). The same approach was used in previous work for the RBD-1C aptamer [8]. The ratio of surface-enhanced Raman signal to fluorescence intensity was decreased in the presence of the virus, providing an excellent limit of detection of SARS-CoV-2 of 100 copies/mL.…”

“…The overall setup is similar to the previously published one [8]. The aptamers were immobilized on the lithographic metal surface, whereas viruses were captured from liquid samples.…”

“…The aptamers were immobilized on the lithographic metal surface, whereas viruses were captured from liquid samples. The specificity and LoDs of the sensors were using the same lithographic substrates as in previous work [8]. The ratio of SERS to SEL (surface-enhanced luminescence) was changed in the presence of the target viruses and was not changed in the pres- Four aptamers with modifications compatible with SERS-based sensors.…”

“…The virus binding changed the distance between the dye and the lithographic metal surface providing the change in the SERS signal from the dye. The sensor detected as low as two viral particles per assay, reliably enabling the detection of a single pathogen in the probe [8]. This simple one-stage approach has been used to create multiplex sensors for the simultaneous detection of four respiratory viruses.…”

Aptamer-coated track-etched membranes with a nanostructured silver layer for single virus detection in biological fluids

“…It is especially significant for analyte determination with low limit of detection ( Kraemer et al, 2011 ). An example of usage of double modified aptamer in SERS-based technique is provided in our recent work ( Kukushkin et al, 2022a ). In that work the aptamer was immobilized onto the metal surface through a thiol group, whereas the Cyanine-3 dye was used as a reporter which signal decreased when the coronavirus (SARS-CoV-2 virus) bound to the aptamer.…”