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Published on: April 21, 2022
A smartphone-based platform for ratiometric visualization of SARS-CoV-2 via an oligonucleotide probe
Tingting Zhao1, Weizhen Yan2, Fengqi Dong3
1School of Basic Medical Sciences, Biopharmaceutical Research Institute, Research and Engineering Center of Biomedical Materials, Anhui Medical University, Hefei, 230032, Anhui, China. ttzhao@ahmu.edu.cn.
Abstract:
COVID-19 necessitates the development of reliable and convenient diagnostic tools. In this work, a facile 3D-printed smartphone platform was constructed that achieved reliable visual detection of SARS-CoV-2 by eliminating the effect of ambient light and fixing the camera position relative to the sample. The oligonucleotide probe is modified with orange-red-emitting TAMRA working as an internal standard and green-emitting FAM serving as a sensitive sensing agent. Under 365-nm UV excitation, the emission wavelengths of TAMRA and FAM are 580 nm and 518 nm, respectively. When the probes interact with the targets, the green fluorescence gradually restores while the orange-red fluorescence remains stable. Thus, a striking color transition from orange-red to green could be observed by the naked eye. The detection limit of SARS-CoV-2 nucleic acid is 0.23 nM, and the entire process of color change could be completed in 25 min. Furthermore, the RGB value analysis of the sample solution was conducted using a smartphone for reliable and reproducible discrimination of SARS-CoV-2. The proposed smartphone platform might establish a general method for visual detection of SARS-CoV-2 nucleic acid as well as other virus-related diseases.
