SARS-CoV-2 Detection Using Colorimetric Plasmonic Sensors: A Proof-of-Concept Computational Study

Abstract

Traditional molecular techniques for SARS-CoV-2 viral detection are time-consuming and can exhibit a high probability of false negatives. In this work, we present a computational study of SARS-CoV-2 detection using plasmonic gold nanoparticles. The resonance wavelength of a SARS-CoV-2 virus was recently estimated to be in the near-infrared region. By engineering gold nanospheres to specifically bind with the outer surface of the SARS-CoV-2 virus, the resonance frequency can be shifted to the visible range (380 nm -700 nm). Moreover, we show that broadband absorption will emerge in the visible spectrum when the virus is partially covered with gold nanoparticles at a specific coverage percentage. This broadband absorption can be used to guide the development of an efficient and accurate colorimetric plasmon sensor for COVID-19 detection. Our observation also suggests that this technique is unaffected by the number of protein spikes present on the virus outer surface, hence can pave a potential path for a label-free COVID-19 diagnostic tool independent of the number of protein spikes.

Sensing of COVID-19 spike protein in nasopharyngeal samples using a portable surface plasmon resonance diagnostic system

“…Herewith, we show the performance of a portable SPR sensor (Figure 1a) using a direct detection scheme for SARS-CoV-2 using VHH-72-Fc bioreceptors (Figure 1b) referring to VHH-72 fused to a human IgG1 Fc domain by a GS(GGGGS)2 linker, as reported by Wrapp et al 17 The sensing platform is competitive with other optical sensing platforms recently described and developed. 37,38 Despite the nanomolar affinity of VHH-72 for the SARS-CoV-2 RBD reported by SPR, 17 the rapid dissociation is believed to effect negatively the SPR read out. The bivalence of VHH-72-Fc, due to the Fc domain of human IgG1 genetically linked by a HHHHHHRENLYFQG linker to the VHH domain (Figure 1), results in nanomolar affinity constant of K D = 1.5×10 -9 M with a k on of 1.2×10 5 M -1 s -1 and an improved k off equal to 1.8×10 -4 s -1 , as determined by the portable P4 SPR (Affinité Instruments) instrument (Figure 2a).…”

“…The sensing device is competitive with other optical sensing platforms recently described and developed. 37,38 By engineering gold nanospheres to distinctively bind with the outer surface of the SARS-CoV-2 virus, the resonance frequency was adjusted to the visible range (380–700 nm). It was shown that the broadband absorption of the virus merges with the visible spectrum when the virus is partially covered with gold nanoparticles at a specific coverage percentage and this feature can be used in efficient and accurate colorimetric plasmon sensors for COVID-19 detection.…”

Nanoparticles as illuminating allies: Advancing diagnostic frontiers in COVID-19- A review

“…They also serve as signal amplifiers in photothermal-based sensing platforms, converting near-infrared light into localized heat upon binding to viral antigens. Furthermore, they showed potential in colorimetric assays, where color changes indicated the presence of viral components (Baidya & Hassan, 2022;Wang et al, 2022). Gold nanocages, characterized by their porous structure, were functionalized with probes for sensitive and selective detection of viral components.…”

“…Gold nanocages, characterized by their porous structure, were functionalized with probes for sensitive and selective detection of viral components. For instance, they were coated with DNA probes that recognized the SARS-CoV-2 spike protein, allowing rapid and specific detection (Baidya & Hassan, 2022). Gold nanocages enhanced the sensitivity and specificity of PCR-based assays by acting as signal amplifiers.…”

“…Lastly, gold nanostars are functionalized with specific probes for highly sensitive detection of viral components. They are used in biosensors, such as SERS, to detect the presence of the virus in patient samples (Baidya & Hassan, 2022). They can also be utilized in LFA for rapid visual virus detection, providing a simple and accessible diagnostic method.…”