A smartphone-based visual biosensor for CRISPR-Cas powered SARS-CoV-2 diagnostics

The pandemic of coronavirus disease 2019 (COVID-19) resulted from novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a worldwide concern. It is imperative to develop rapid, sensitive, and specific biosensing methods. Herein, we developed a CRISPR-Cas12a powered visual biosensor with a smart phone readout for ultrasensitive and selective detection of SARS-CoV-2. Simply, the SARS-CoV-2 derived nucleic acids triggered CRISPR-Cas12a based indiscriminate degradation of a single-stranded DNA that was supposed to link two gold nanoparticles, inducing the dis-aggregation of gold nanoparticles and thus generating observable color changes. This change can be readily distinguished by naked eyes as well as a smartphone with a Color Picker App. The proposed biosensor was successfully applied to detect SARS-CoV-2 gene in synthetic vectors, transcribed RNA and SARS-CoV-2 pseudoviruses. It rendered single copy resolution as evidenced by the 1 copy/mu L limit of detection of pseudoviruses with no cross-reactivity. When the developed biosensor was challenged with SARS-CoV-2 clinical bio-samples, it provided 100% agreement (both positive and negative) with qPCR results. The sample-to-result time was roughly 90 min. Our work provides a novel and robust technology for ultrasensitive detection of SARS-CoV-2 that could be used clinically.

Automated summary

Researchers have developed a CRISPR-Cas12a powered biosensor for ultra-sensitive and selective detection of SARS-CoV-2, with smartphone readout capability. The biosensor showed excellent performance in detecting synthetic vectors, transcribed RNA, and pseudoviruses, providing 100% agreement with qPCR results when tested with clinical samples. It offers a novel and robust technology for clinically sensitive detection of SARS-CoV-2.