Handheld biofluorometric system for acetone in the exhaled breath condensates

Abstract

As a marker of human metabolism, acetone is important for lipid metabolism monitoring and early detection of diabetes. In this study, we developed a handheld acetone biosensor based on fluorescence detection by utilizing the enzymatic reaction of secondary alcohol dehydrogenase (S-ADH) with β-nicotinamide adenine dinucleotide (NADH, λex = 340 nm, λem = 490 nm). In the reaction, NADH is oxidized when acetone is reduced to 2-propanol by S-ADH, and acetone concentration can be measured by detecting the amount of NADH consumed in this reaction. First, we constructed the compact and light weight fluorometric NADH detection system (209 g for the sensing system and 342 g for PC) which worked with battery. Then, sensor characteristics were evaluated after optimization of working conditions. The developed system was able to quantify the acetone at a range of 510 nM to 1 mM within 1 minute. The developed battery-operated acetone biosensor demonstrated its ability to measure acetone concentration in exhaled breath condensate of 10 healthy subjects at rest (23.4±15.1 μM) and 16 h of fasting (37.7±14.7 μM) and distinguish with significant differences (p = 0.011). With the advantages of handholdable, high sensitivity and selectivity, this sensor is expected to be widely used in clinical diagnosis and wearable biochemical sensors in the future.