An electrochemical probe for the ultrasensitive detection of long non-coding RNA biomarkers

Long non-coding RNAs (lncRNAs) are cutting-edge genome sequences of non-coding RNA that have emerged as key gene expression regulators. Homeobox transcript antisense intergenic RNA (HOTAIR) is an lncRNA diagnostic biomarker that directly affects apoptosis regulation and is associated with malignant cancer. Therefore, HOTAIR ultrasensitive detection is vastly crucial. In this study, we constructed a robust biosensor based on an Au-crumpled graphene/polystyrene (PS) substrate for sensing HOTAIR. High-quality chemical vapor deposition (CVD)-grown graphene was attached to the PS substrate, and heated crumpled graphene was formed through physical stacking forces. Subsequently, the gold was uniformly coated using the thermal evaporation method to enhance sensitivity, and the specimen was treated with a low-damage plasma treatment to induce active oxygen functionalization at the surface. The single-stranded DNA probe was then immobilized to the modified electrode, and the device was characterized. A linear working in the range of 1 fM–100 pM was determined with an ultralow detection limit of 149 aM. The biosensor detects HOTAIR selectively in the presence of base-mismatched sequences, and its suitability for human serum analysis was assessed. Thus, this system could be used to monitor HOTAIR as a diagnostic biomarker to detect early cancer and assess disease progression.