Neurofilament light chain (NFL) is widely used as a marker of neuronal damage in MS. Increased NFL levels in MS patients correlate with patient disability, disease activity, brain atrophy, and spinal cord volume loss. Single Molecule Array (SIMOA), the state-of-the-art technique for detecting NFL in biological fluids, requires time, specialized equipment and a dedicated laboratory with trained personnel.
Electrolyte-dependent organic field-effect transistors (EGOFETs) are emerging as a highly versatile biosensing platform. EGOFET biosensors possess the ideal characteristics needed to monitor chronic disease biomarkers: they require relatively low power to operate, can be fabricated on cheap and disposable substrates, can be miniaturized and integrated with microfluidics. We have recently developed an EGOFET biosensor that detects NFL with high sensitivity and specificity, making it capable of detecting NFL at pathophysiological concentrations. In parallel, we have developed an EGOFET device capable of monitoring. We have also developed a second biosensor capable of detecting mitochondrial DNA (mtDNA) with high specificity and sensitivity, also considered a marker of cell damage and which we have recently demonstrated to increase in patients with SP-MS. In this project, we intend to test the developed biosensors on serum and plasma samples of MS patients with PP and SP forms, to evaluate i) if the EGOFET biosensor can detect NFL in real samples of MS patients and ii) if its performance (accuracy, specificity and sensitivity) is comparable to that of SIMOA; iii) whether the performance of the device for mtDNA quantification is comparable to the current standard (ddPCR). From a clinical point of view, we will determine serum levels of NFL and mtDNA and le in patients with and without progression, to evaluate the prognostic utility of baseline levels in determining disease progression in patients with PP- and SP-SM.
To this end, we will evaluate the specificity and sensitivity of the NFL and mtDNA biosensors on samples of increasing complexity (from PBS to serum) with known concentrations of NFL and mtDNA. Then, we will determine the LOD of the biosensors under these conditions and optimize the electrical parameters to maximize the intra-assay and inter-assay reproducibility. Finally, we will analyze serum and plasma samples from 34 PP- MS and SP-MS enrolled in the study, at baseline and after 6 months. The concentrations of NFL and mtDNA will be evaluated with the two biosensors, and compared with the standard technologies used today. Longitudinal changes in NFL and mtDNA will be correlated with clinical parameters to determine if baseline levels are predictive of disease worsening.