Poster Y6 - Point-of-care Approach With Post-synthetic Modification in Covalent Organic Nanosheets For Rapid Quantitative Detection Of Mild Traumatic Brain Injury

Introduction: Traumatic brain injury (TBI) in the US causes 2 million fatalities annually and costs $76.3 billion. Accurate, timely, and quick diagnosis of mild TBI is crucial for successful intervention. Current diagnostics rely on expensive, time-consuming, and inaccessible MRIs and CT scans. Biofluid-based biomarkers have been introduced for early diagnosis, but blood-based biomarkers remain challenging. A quick bio-diagnostic test can identify individuals needing CT imaging, and a technology for accurately measuring three mTBI-related microRNAs in saliva can improve medical care. We have fabricated a portable potentiostat-based electrochemical sensor with phloroglucinol-based covalent organic framework (COF) for a point-of-care device. With the combination of redox pair, host-guest chemistry and COF-based additive on the surface of the electrode, we have reached picomolar sensitivity with the electrochemical sensor for accurate mTBI detection. The surface-functionalization of the gold electrodes required designed post-synthetic COF modification and host-guest complex conjugation to attain such sensitivity for a ready-to-use device.

Materials and

Methods: A phloroglucinol-based covalent organic framework (COF) was post-synthetically modified with (3-glycidoxypropyl)trimethoxysilane (GPTMS) to introduce epoxy groups, enabling the immobilization of streptavidin. These streptavidin-functionalized COFs were conjugated with methylene blue-labeled and biotinylated antisense oligonucleotides (ASOs) targeting mTBI-specific microRNA (miRNA) sequences. To enhance electrochemical detection, the ASO-functionalized COFs were deposited onto gold electrodes modified with a nafion layer, followed by a PEDOT:PSS coating. Hybridization of target miRNAs with the ASOs on the electrode surface resulted in detectable changes in the electrochemical signal, allowing for the quantification of miRNA levels.

Results, Conclusions, and Discussions: Picomolar quantities of miRNA were successfully found in saliva samples from patients who had mild traumatic brain damage (mTBI) with electrochemical detection. The sensitivity and specificity of the sensor with COF's post-synthetic alteration and the use of PEDOT:PSS for signal amplification, present a viable option for mTBI non-invasive diagnostics. Interestingly, our findings are consistent with research finding particular miRNAs (miR-let7a, miR-21, miR-30e) linked to mTBI in saliva and other biofluids. The approach raises the possibility of creating a multi-marker panel to enhance diagnostic precision and comprehend the fundamental mechanisms of mTBI. There are around 30 miRNA markers that can be upregulated during mild traumatic brain injury. Targeting all of them through multiplexing our approach can provide immense benefits for brain injury-related diagnosis. Other Covalent organic frameworks can also be used for multi-modal detection of the miRNAs through differential post-synthetic modifications.

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