A CRISPR-amplified label-free electrochemical aptasensor for the sensitive detection of HbA1c†

Glycated hemoglobin (HbA1c) is a pivotal biomarker for the monitoring and early diagnosis of diabetes. The CRISPR-Cas system has fascinating application prospects in the next generation of biosensors due to its high specificity, efficiency, flexibility, and customization. Herein, a label-free electrochemical aptasensor was designed for the detection of HbA1c by combining the specific recognition ability of aptamers with the signal amplification effect of the CRISPR-Cas12a system. In the presence of HbA1c, the cis–trans cleavage ability of Cas12a protein was activated, causing the pre-formed probe DNA to be heavily cleaved and the electrochemical signal to increase. With CRISPR-assisted signal amplification, the developed electrochemical aptasensor can detect as low as 0.84 ng mL⁻¹ HbA1c. Moreover, this aptasensor can detect 10 ng mL⁻¹ HbA1c in 50% human serum due to its high selectivity, reproducibility, and long-term stability, which is lower than its physiological level in human blood samples. All results proved that the proposed aptasensor has a promising application in the early diagnosis and long-term monitoring of diabetes.