Tailored Anti-miR Decorated Covalent Organic Framework Enables Electrochemical Detection of Salivary miRNAs for Mild Traumatic Brain Injury

Abstract

MicroRNAs (miRNAs) play pivotal role as biomarkers for various diseases, with salivary miRNAs offering a non-invasive diagnostic tool. For mild traumatic brain injury (mTBI), salivary miRNAs like miR-let7a, miR-21, and miR-30e show promise for early detection of subtle injuries lacking reliable indicators. To advance the detection of mTBI-related salivary miRNAs, this study integrates anti-miRNA and miRNA hybridization-based sensing with the development of a nanoscale covalent-organic framework (COF) platform. COFs, with their highly customizable structures, large surface area, and biocompatibility, serve as a versatile foundation for biosensing applications. Here, post-synthetic modification (PSM) of COFs is introduced for essential covalent conjugation of streptavidin for further immobilization of methylene blue-labeled and biotinylated Anti-miRNAs. Furthermore, the layer-by-layer assembly of conductive polymers enhanced the biosensor's electrical performance, enabling ultrasensitive and multiplexed detection of salivary miRNAs. Validated with samples from mixed martial arts participants and confirmed by polymerase chain reaction (PCR), this COF-based platform demonstrates robust accuracy and reliability. By combining COF functionalization with advanced electrode design, it offers a powerful, non-invasive solution for early mTBI detection and broader biomedical applications.