Biosens. Bioelectron. | Nanozyme test strips achieve rapid and highly sensitive nucleic acid detection of the new coronavirus
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*This article was first published on the "Nanozymes" public account. October 18, 2022
* Editor: Du Jiang
The new crown pneumonia epidemic caused by SARS-CoV-2 is still raging around the world, having a serious impact on human health, life and economy. Rapid and highly sensitive screening of positive patients and timely isolation is an effective means to control the epidemic. nucleic acid detection based on reverse transcription polymerase chain reaction (RT-PCR) has higher sensitivity and specificity than antigen and antibody detection, and is the current gold standard for COVID-19 detection. However, the method is long and requires professionals to operate in biosafety laboratory , which is not conducive to large-scale development in remote areas and low-income countries, and cannot be used for home self-testing. To solve this problem, the development of a simple, fast, low-cost and highly sensitive instant detection technology is crucial to the detection and prevention of the new coronavirus.
Yan Xiyun Academician's team has been committed to the development and application research of nanoenzymes (a class of nanomaterials containing enzymatic properties). The developed nanoenzyme test strips have achieved rapid and highly sensitive detection of Ebola and new coronavirus antigens (Biosensors and Bioelectronics, 2015, 2021). Based on this work, we combined nanoenzyme test strips with recombinase polymerase isothermal amplification technology for rapid and highly sensitive detection of new crown nucleic acids (Biosensors and Bioelectronics, 2022). The schematic diagram is as follows. Isothermal amplification technology can amplify the nucleic acid of the new coronavirus at 39°C and 20 minutes, and the amplified product is labeled with biotin and digoxin. The quality control line of the test strip is sprayed with biotin-bovine serum albumin complex, anti-digoxin antibody is present at the detection line, and streptavidin is modified on the FeS2 nanoenzyme to form a nanoenzyme probe. When the new crown amplification product is present, the biotin at one end of the product will bind to the nanoenzyme probe and then be captured by digoxin antibody at the detection line, so that the detection line will show the color of the nanoenzyme. Excess nanoenzyme probes are further combined with the quality control line. The nanoenzymes at the detection line and the quality control line exert their high peroxidase activity to catalyze the substrate TMB for color development, thereby amplifying the signal and improving detection sensitivity.
Figure 1. The principle of nanoenzyme test strips to achieve viral nucleic acid detection
This method can detect new crown nucleic acid within 36 minutes, with a sensitivity of 200 copies/mL, close to the level of RT-PCR.
Figure 2. Nanoenzyme test strips to detect nucleic acid
of SARS-CoV-2 using this method to detect clinical samples of HPV-16. The results are completely consistent with the diagnostic results of RT-PCR, proving the universality and reliability of this method.
Figure 3. Nanoenzyme test strips detect nucleic acid
in clinical samples of HPV-16. Importantly, in previous studies of nanoenzyme test strips, toxic DAB is usually needed to use as a catalytic substrate. The FeS2 nanoenzyme developed in this work, due to its unique catalytic performance, the test strips can use non-toxic TMB as a catalytic substrate and achieve signal amplification and sensitivity improvement. This technology not only expands the application range of nanoenzyme test strips from protein detection to nucleic acid detection, but also has great potential in the development of POCT diagnostic technology for new crown and other viruses.
Academician Yan Xiyun, Researcher Duan Demin and Researcher Gao Lizeng from the Institute of Biophysics, Chinese Academy of Sciences are the corresponding authors of in this article, and Dr. Meng Xiangqin and Master Zou Sijia students are the co-first authors of this article.
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