A CRISPR-Cas12a powered electrochemical sensor based on gold nanoparticles and MXene composite for enhanced nucleic acid detection

Rapid and accurate detection of nucleic acids plays a critical role in public health, food safety and environmental management. Clustered regularly interspaced short palindromic repeats powered electrochemical sensor (E-CRISPR) is attractive as a point-of-care (POC) testing platform to fulfil this purpose. Yet, bulk noble metals (e.g., gold and platinum) based electrodes that have been widely adopted in E-CRISPR suffer from limited analytical performance and high manufacturing costs. Here, to address this limitation, we present a carbon-based E-CRISPR modified with gold nanoparticles and MXene Ti3C2 (a class of two-dimensional transition metal carbide nanomaterials) that provides highly stable and sensitive transduction of CRISPR-Cas12a trans-cleavage activity. Through systematic evaluation and optimization, our AuNPs/MXene Ti3C2 based E-CRISPR achieve the quantification of human papillomavirus 18 (HPV-18) DNA with a wide range of concentrations from 10 pM to 500 nM with a detection limit of 1.95 pM. We further evaluate the selectivity, degradation resistance and detection capability of the developed sensor during long-term storage. Notably, AuNPs/MXene based E-CRISPR retain more than 70% of initial current after 2 months and deliver reliable analytical results that are unaffected over 42-day storage. Owing to its excellent biofouling-resistant and analytical performance and robust shelf life, our E-CRISPR sensor offers a universal, scalable and low-cost strategy for POC nucleic acid testing.