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Enzyme Biosensor for Ultrasensitive Detection of Formaldehyde in Urine

Enzyme Biosensor for Ultrasensitive Detection of Formaldehyde in Urine

Gayan Premaratne


Identifying deadly diseases using specific small molecule markers at an early stage of disease would decrease fatality rate. Formaldehyde has recently been recognized as one of the key small molecular biomarkers elevated in body fluids for Dementia, Alzheimer and bladder cancer. Our goal is to develop an electrochemical biosensor for non-invasive detection of low levels of formaldehyde in urine. Our biosensor design involves screen-printed electrodes (SPEs) modified with carbon nanotubes (CNTs) pi-pi stacked with pyrene compounds to covalently attach formaldehyde dehydrogenase (FDH) by carbodiimide chemistry. The enzyme selective catalysis by FDH converts formaldehyde to formic acid, using NAD+ as the electron acceptor to yield NADH. The electrons from NADH is mediated to the electrode surface by 1, 2-napthaquinone sulfonic acid. The main advantage of using NAD-dependent dehydrogenase-based biosensors is that O2 does not interfere with the electrochemical formaldehyde detection. The designed enzyme biosensor offered a detection limit of 6 ppb in 10-times diluted urine with a wide dynamic range of 10 ppb to 10 ppm. Our future research will focus on developing a multiplexed system for detecting key small molecular biomarkers for cancers in clinical matrices.