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image: (A) Genetic algorithm-driven computational screening and fabrication of the nanoplasmonic SERS aptasensor metasurfaces. Flowchart for genetic algorithm and computational screening of periodic gold nanostructures for maximizing the Raman cross-section of the metasurfaces, Scanning emission microscopy images of the e-beam lithography fabrication for optimized periodic gold nanopattern over 200-μm × 200-μm area. (B) Gold-nanopatterned metasurface is functionalized using a thiol-modified primary aptamer that is specific for SARS-CoV-2 spike glycoproteins. Unprocessed COVID-19 patient saliva or inactive SARS-CoV-2 sample is mixed with fluorescent secondary aptamer, resulting in virus–secondary aptamer complex. Sample is dropped onto the metasurface modified with the primary aptamer to form a sandwich structure (primary aptamer, SARS-CoV-2, and secondary aptamer). Aptamers capture the SARS-CoV-2 by binding to virus glycoproteins, forming a sandwich structure yielding strong plasmonic enhancement of the virus-specific fluorescent and Raman emissions. These Raman spectra are then used in the machine learning classifier model for viral presence, concentration, and variant type. a.n., arbitrary numbers.
Credit: Advanced Devices & Instrumentation
As detailed in "Rapid Nanoplasmonic-Enhanced Detection of SARS-CoV-2 and Variants on DNA Aptamer Metasurfaces," the research focuses on the development of DNA aptamer-based metasurfaces for the enhanced detection of SARS-CoV-2 and its variants. By integrating nanoplasmonic elements with aptamer-functionalized metasurfaces, the study achieved remarkable improvements in sensitivity and specificity. The synergy between the unique properties of metasurfaces and the high affinity of DNA aptamers allows for rapid and reliable detection of the target viruses.
Primary and secondary aptamers capture the viruses on the specifically designed and manufactured for nanoplasmonic enhancement. Primary aptamers are used to functionalize the gold nanopatterned metasurface via thiol bonds and secondary aptamers are used to create fluorescent effect via the Cy5.5 dye modification. The virus is trapped in between primary and secondary aptamers, forming a sandwich structure. Plasmonic enhancement and fluorescent signal paved the way for the detection of viruses through Raman and fluorescent signal. Machine learning is used to classify the SERS and fluorescent spectra and allowed the identification of different variants with near-perfect accuracy. The sensitivity and specificity in 69 clinical SARS-CoV-2 patients was determined as 95.2%.
The rapid nanoplasmonic-enhanced detection enabled by DNA aptamer metasurfaces holds promise for efficient screening of SARS-CoV-2 and its variants in clinical settings, airports, and other high-traffic areas. The sensitivity and speed of this approach open avenues for early detection, contributing to effective disease control and prevention strategies.
Advanced Devices & Instrumentation
News article
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Rapid Nanoplasmonic-Enhanced Detection of SARS-CoV-2 and Variants on DNA Aptamer Metasurfaces
11-Apr-2023
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