Fluorescent bionanosensor for picomolar detection of biomarkers in fluids

Fast and simple detection of diseases at their early stage and clinical monitoring of healing progress directly from body fluids, namely from urine, is a hot topic in modern personalized medicine. Functionalized nanofibers seem to be an ideal solution for the construction of specific and highly selective detection systems and microfluidic tools due to their extremely high ratio between their surface and volume, and also tunable sensitivity. The aim of this study is development of biosensors based on functionalized nanofibers leading to signal enhancement which would enable fluorescence detection and improve diagnostic accuracy in human fluids. Functionalized-PolyAcrylNnitrile (fPAN) membranes were fabricated and analyzed via SEM and fluorescence spectroscopy. Biotin-FITC binding was tested using a routine filtration setup and quantified with a Fluoromax4 spectrometer. Avidin-functionalized membranes showed strong, specific binding at picomolar levels Since the collected urine can be easily collected at volumes of more than 100 mL, and fluorescence measurement performed at a significantly smaller volume than 1 mL, our nanofiber-based system serves as an efficient specific enhancer and increases, thus, the detection limit by more than two orders of magnitude. This is already sufficient, for example, for a reliable fluorescence detection of urine markers in subpicomolar concentrations. Thus, this study describes a novel detection approach and application of fluorescence bionanosensors based on specifically functionalized polyacrylonitrile nanofibers for monitoring of subpicomolar concentrated markers in human fluids. These concentrations allow already monitoring of serious diseases at their early stage, which is crucial for distant and precision medicine.