Development of Label-Free Colorimetric Assay for MERS-CoV Using Gold Nanoparticles

Abstract

Worldwide outbreaks of infectious diseases necessitate the development of rapid and accurate diagnostic methods. Colorimetric assays are a representative tool to simply identify the target molecules in specimens through color changes of an indicator (e.g., nanosized metallic particle, and dye molecules). The detection method is used to confirm the presence of biomarkers visually and measure absorbance of the colored compounds at a specific wavelength. In this study, we propose a colorimetric assay based on an extended form of double-stranded DNA (dsDNA) self-assembly shielded gold nanoparticles (AuNPs) under positive electrolyte (e.g., 0.1 M MgCl 2 ) for detection of Middle East respiratory syndrome coronavirus (MERS-CoV). This platform is able to verify the existence of viral molecules through a localized surface plasmon resonance (LSPR) shift and color changes of AuNPs in the UV−vis wavelength range. We designed a pair of thiol-modified probes at either the 5′ end or 3′ end to organize complementary base pairs with upstream of the E protein gene (upE) and open reading frames (ORF) 1a on MERS-CoV. The dsDNA of the target and probes forms a disulfide-induced long self-assembled complex, which protects AuNPs from salt-induced aggregation and transition of optical properties. This colorimetric assay could discriminate down to 1 pmol/μL of 30 bp MERS-CoV and further be adapted for convenient on-site detection of other infectious diseases, especially in resource-limited settings.

Recent advances and perspectives of nucleic acid detection for coronavirus

“…The fight against infectious diseases caused by viruses remains a challenging and endless task despite the tremendous efforts and significant advances in public healthcare. Infectious diseases pose a significant risk to human health and have led to approximately onefourth of deaths worldwide [1,2]. Coronaviruses belong to the family of Coronaviridae and may cause respiratory and neurological diseases [3].…”

Laboratory detection methods for the human coronaviruses

“…Free or immobilized DNA probes were tagged with transducing elements in advance or become subjected to them after hybridizing with the targets. Electrochemical [100][101][102][103] and optical agents [24,37,77,[104][105][106] are examples of transducers that have been employed in these gene-based sensors to produce measurable signals corresponding to the presence or absence of viral RNA. Figure 5 presents a schematic of the principle underlying of these biosensors.…”

Biomedical Science to Tackle the COVID-19 Pandemic: Current Status and Future Perspectives

“…In this regard, Kim et al recently reported colorimetric trials to identify targeted biomolecules through LSPR shifts and color changes in spherical AuNP suspensions by selecting a target and a control upstream of the E protein gene (upE) and open reading frames (ORF) 1a of MERS-CoV and tobacco mosaic virus (TMV), respectively [ 218 ]. This is based on the interaction of the negatively charged citrate ion-capped AuNPs with disulfides, salts and targeted probes.…”