Gold-Deposited Laser-Induced Graphene Electrode for Detection of miRNA-141

Oncogenic microRNAs (miRNAs) are frequently upregulated in various cancers, including prostate cancer, and have been implicated in promoting tumor growth, invasion, and metastasis. Here, we developed an electrochemical biosensor for detecting miRNA-141, a key prostate cancer biomarker, using gold nanoparticles (AuNPs) decorated laser-induced graphene (LIG) electrodes. The LIG was stenciled on polyimide film attached to a polyethylene terephthalate sheet, followed by electrochemically depositing AuNPs to enhance the effective surface area and electron transfer kinetics. The morphology of the electrode was characterized using scanning electron microscopy. The average diameter of the AuNPs deposited on the LIG electrode measured around 50-60 nm in diameter. Thiolated ss-DNA was immobilized onto the surface of the LIG/AuNPs electrode as the biorecognition element for miRNA-141. The developed biosensor demonstrated an excellent sensitivity toward miRNA-141 biomarkers over a linear response of 10 fM-10 nM with a detection limit of 0.67 fM. The biosensor exhibited excellent electrochemical activity and sensitivity due to the enhanced surface area for higher ss-DNA loading and the synergistic effects of the LIG and AuNPs. In conjunction with other clinical parameters and biomarkers, this ultrasensitive electrochemical biosensor can potentially improve early diagnosis of prostate cancer.