Smartphone-Interfaced Electrochemical Biosensor for microRNA Detection Based on Laser-Induced Graphene with π–π Stacked Peptide Nucleic Acid Probes
Sharat Chandra Barman, Muhsin Ali, Erol Hasan, Nimer Wehbe, Husam N. Alshareef, Dana Alsulaiman
Abstract
High Resolution Image Download MS PowerPoint Slide The development of ultrasensitive, rapid, and robust point-of-care devices for biomarker detection holds great promise to revolutionize clinical diagnostics. Notably, microRNA has demonstrated significant potential as a minimally invasive cancer biomarker; however, conventional approaches for their detection require costly multistep procedures, bulky equipment, and trained personnel. Herein, we develop a peptide nucleic acid (PNA)-functionalized laser-induced graphene biosensor based on a single-step fabrication and single-step probe functionalization strategy, with a smartphone-based readout. Immobilization of a bespoke 1-pyrenebutyryl-N-end-terminated 17 mer PNA through π–π stacking on graphene was validated via Raman and X-ray photoelectron spectroscopy. As a proof-of-concept, the biosensor is applied to the detection of a prostate cancer biomarker, hsa -miR-141, exhibiting excellent analytical performance with high specificity and a limit of detection of 0.6 aM, without requiring amplification, enzymes, or thermal cycling. The versatility of this portable amplification-free platform and its ease of fabrication facilitate its translation into a point-of-care device with the potential to revolutionize clinical diagnostics, even in resource-limited settings.