Smartphone-assisted self-powered dual-mode biosensor designed on binary 3D DNA Walkers mediated CRISPR/Cas12a system

Malignant tumors are significant diseases that pose a threat to human life and health. The advancement of highly sensitive and specific methods is of excellent significance. This study proposes a novel detection platform that employs a smartphone-assisted self-powered sensing system with binary 3D DNA Walkers mediated CRISPR/Cas12a system and ultra-thin 2D graphdiyne for ultrasensitive dual-mode detection of breast cancer biomarker microRNA-let-7a. The binary 3D DNA Walkers possess high efficiency in movement and multifunctional characteristics. When combined with the CRISPR/Cas12a system, they can retain the advantages of 3D DNA Walker while releasing a large of trigger strands complementary to CRISPR RNA, thereby greatly enhancing the sensitivity of the sensor. In addition, capacitors are also integrated into the sensing system to further amplify the detection signal, resulting in a 20.7-fold increase in sensitivity of the method. Additionally, the adoption of an electrochemical/colorimetric dual-mode detection strategy significantly enhances the accuracy of the new approach. The newly developed detection method exhibits a linear range of 0.0001–10000 pM with a detection limit of 8.11 aM (S/N = 3). This work offers a reliable portable sensor for sensitive and accurate detection of tumor biomarkers, enabling remote disease sensing and on-site monitoring applications.