A New Ultrasensitive Single-Molecule Assay for Frataxin Measurement

These investigators propose to develop a sensitive and quantitative assay for measuring frataxin levels that could help drug development in FA as well as advance our understanding of disease mechanisms. Direct measurement of frataxin remains challenging owing to its low abundance and the inherent detection noise of commonly used assays. Dr Jain and Dr Mouro Pinto propose to overcome this hurdle by implementing a technology that allows detection of very small amounts of molecules directly from serum, blood, or tissue extracts. This method, called SiMPull, combines immuno pull-down (isolating a molecule with antibodies) with single-molecule microscopy, allowing the visualization of single protein molecules with a microscope. This assay was recently utilized to measure a variety of biomarkers in blood present at very low concentrations. The investigators hypothesize that the increased sensitivity, quantitative readout, and dynamic range afforded by SiMPull will allow to accurately quantify frataxin levels, including measurements of subtle changes that are undetectable by conventional methods. SiMPull may provide opportunities to use frataxin in accessible biospecimens such as blood, serum, and cerebrospinal fluid as a biomarker for disease progression and for assessing the effectiveness of therapies in clinical trials.