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

https://doi.org/10.1016/j.bios.2021.113646Get rights and content

Highlights

  • A smartphone-read CRISPR-Cas12a powered visual biosensor was developed.

  • This biosensor was capable of detecting SARS-CoV-2 gene in synthetic vectors, transcribed RNA and SARS-CoV-2 pseudoviruses.

  • The limit of detection for SARS-CoV-2 pseudoviruses was 1 copy/μL with no cross-reactivity.

  • The biosensor showed 100% positive and 100% negative agreement with qPCR results for clinical samples detection.

Abstract

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 smartphone 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/μL 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.

Keywords

CRISPR-Cas12a
Gold nanoparticles
SARS-CoV-2 detection
Smartphone-based diagnostics
Visual biosensor
Clinical samples

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1

The first four authors contributed equally and shared the joint first authorship.

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