Dual signal amplification in ECL biosensors: A novel approach for argonaute2 detection using SAHARA CRISPR-Cas12a technology

Argonaute 2 (Ago2) is a crucial enzyme in the RNA interference (RNAi) pathway, essential for gene silencing via the cleavage of target messenger RNA (mRNA) mediated by microRNA (miRNA) or small interfering RNA (siRNA). The activity of Ago2 is a significant biomarker for various diseases, including cancer and viral infections, necessitating precise monitoring techniques. Traditional methods for detecting Ago2 activity are often cumbersome and lack the necessary sensitivity and specificity for low-abundance targets in complex samples. This study presents an innovative biosensor utilizing electrochemiluminescence (ECL) technology combined with the SAHARA (Split Activator for Highly Accessible RNA Analysis) CRISPR-Cas12a system to detect Ago2 activity with high sensitivity and specificity. The introduction of Blocker RNA in the activation mechanism enhances the specificity of CRISPR-Cas12a, ensuring accurate signal generation. The dual signal amplification strategy, combining RISC-assisted and CRISPR-Cas12a-mediated cleavage, enhances the biosensor's sensitivity. The developed ECL biosensor demonstrated a remarkable limit of detection (LOD) of 0.145 aM, along with excellent precision, stability, and specificity. These attributes make it a powerful tool for detecting Ago2 activity in clinical diagnostics and research settings.