Amplification-free detection of Mycobacterium tuberculosis using CRISPR-Cas12a and graphene field-effect transistors†

Abstract

Current molecular tests for tuberculosis (TB), such as whole genome sequencing and Xpert Mycobacterium tuberculosis/rifampicin resistance assay, exhibit limited sensitivity and necessitate the pre-amplification step of target DNA. This limitation greatly increases detection time and poses an increased risk of infection. Here, we present a graphene field-effect transistor (GFET) based on the CRISPR/Cas system for detecting Mycobacterium tuberculosis. The CRISPR/Cas12a system has the ability to specifically recognize and cleave target DNA. By integrating the system onto the FET platform and utilizing its electrical amplification capability, we achieve rapid and sensitive detection without requiring sample pre-amplification, with a limit of detection (LoD) as low as 2.42 × 10⁻¹⁸ M. Cas12a-GFET devices can differentiate 30 positive cases from 56 serum samples within 5 minutes. These findings highlight its immense potential in future biological analysis and clinical diagnosis.