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Chung-Ang University Researchers Show A Gold-Paved Path Towards Faster COVID-19 Diagnosis
Researchers use gold nanoparticles to develop a new molecular diagnostic platform that considerably reduces the time required for COVID-19 detection
The RT-PCR test, the current diagnostic standard for COVID-19, is considerably time-consuming. To shorten the time required for SARS-CoV-2 detection, researchers have developed a nanotechnology-based platform called “SERS-PCR” using a “gold nanoparticle-internalized nanodimple” substrate. This new molecular diagnostic platform reduces the number of PCR cycles required to amplify and detect viral genes as compared to conventional RT-PCR, allowing more rapid diagnosis and helping in the mitigation of COVID-19 transmission.
The new SERS-PCR technique could enable more rapid COVID-19 diagnosis, which will help in curtailing the spread of the disease. "Michigan National Guard" by The National Guard is licensed under CC BY 2.0.
The rapid spread of COVID-19, a disease caused by the SARS-CoV-2 virus, has created a public health crisis around the world. While vaccination campaigns are currently underway, early COVID-19 detection and isolation are key for controlling disease transmission and protecting vulnerable populations. The current standard for COVID-19 diagnosis is reverse transcriptase-polymerase chain reaction (RT-PCR), a technique in which viral genes are detected after they undergo multiples cycles of amplification. However, this technique is time-consuming, creating a testing backlog across diagnostic centers and leading to delayed diagnosis. Given the unpredictable nature of spikes in COVID-19 transmission, new approaches that allow faster diagnosis are the need of the hour.
Providing newfound hope is a recent study published in Biosensors and Bioelectronics, in which researchers from Korea and China have introduced a novel nanotechnology-based platform that can shorten the time required for COVID-19 diagnosis. Their surface-enhanced Raman scattering (SERS)-PCR detection platform—prepared using gold nanoparticles (AuNPs) in the cavities of Au ‘nanodimple’ substrates (AuNDSs)—can detect viral genes after only 8 cycles of amplification. That is almost one-third of the number required with conventional RT-PCR. This paper was made available online on October 31, 2021, and was published in volume 197 of the journal on February 1, 2022.
“Conventional RT-PCR is based on the detection of fluorescence signals, so 3–4 hours are required to detect SARS-CoV-2. This speed is not enough considering how rapidly COVID-19 spreads. We wanted to find a way to cut this time at least by half,” says Prof. Jaebum Choo, explaining the motivation behind the study. Fortunately, the answer was not too far. In a previous study published in 2021, Prof. Choo’s team had developed a novel detection platform in which high-sensitivity SERS signals are produced by AuNPs uniformly arranged in the cavities of AuNDSs through a technique called DNA hybridization. Based on this previous discovery, Prof. Choo and his team developed the novel SERS-PCR platform for COVID-19 diagnosis.
The newly developed SERS-PCR assay uses SERS signals to detect “bridge DNA”—small DNA probes that slowly break down in the presence of target viral genes. Therefore, in samples from patients positive for COVID-19, the concentration of bridge DNA (and therefore the SERS signal) continuously decreases with progressive PCR cycles. In contrast, when SARS-CoV-2 is not present in the sample, the concentration of bridge DNA and the resultant SERS signal remain unchanged. In this way, SARS-CoV-2 can be rapidly detected in patient samples.
The team tested the effectiveness of their system using two representative target markers of SARS-CoV-2, namely, the envelope protein (E) and RNA-dependent RNA polymerase (RdRp) genes of SARS-CoV-2. While 25 cycles were required for RT-PCR-based detection, the AuNDS-based SERS-PCR platform required only 8 cycles, considerably reducing the testing duration. “Although our results are preliminary, they provide an important proof-of-concept for the validity of SERS-PCR as a diagnostic technique. Our AuNDS-based SERS-PCR technique is a promising new molecular diagnostic platform that can considerably shorten the time required for gene detection compared to conventional RT-PCR techniques. This model can be further expanded by incorporating an automatic sampler to develop a next-generation molecular diagnostic system,” explains Prof. Choo.
Indeed, SERS-PCR could be an important tool in our arsenal against the COVID-19 pandemic. It could also create a paradigm shift in the field of molecular diagnostics, revolutionizing how we detect infectious diseases and tackle future epidemics.
Title of original paper
SERS-PCR assays of SARS-CoV-2 target genes using Au nanoparticles-internalized Au nanodimple substrates
Biosensors and Bioelectronics
1 Department of Chemistry, Chung-Ang University, Seoul, 06974, South Korea
2 Nano-Bio Convergence Department, Korea Institute of Materials Science KIMS, Changwon, 51508, South Korea
3 Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China