A fiber-optic sorbitol biosensor based on NADH fluorescence detection toward rapid diagnosis of diabetic complications

Abstract

Accumulation of sorbitol in the tissue is known to cause microvascular diabetic complications. In this paper, a fiber-optic biosensor for sorbitol which is used as a biomarker of diabetic complications was developed and tested. The biosensor used a sorbitol dehydrogenase from microorganisms of the genus Flavimonas with high substrate specificity and detected the fluorescence of reduced nicotinamide adenine dinucleotide (NADH) by the enzymatic reaction. An ultraviolet light emitting diode (UV-LED) was used as the excitation light source of NADH. The fluorescence of NADH was detected using a spectrometer or a photomultiplier tube (PMT). The UV-LED and the photodetector were coupled using a Y-shaped optical fiber. In the experiment, an optical fiber probe with a sorbitol dehydrogenase immobilized membrane was placed in a cuvette filled with a phosphate buffer containing the oxidized form of nicotinamide adenine dinucleotide (NAD + ). The changes in NADH fluorescence intensity were measured after adding a standard sorbitol solution. According to the experimental assessment, the calibration range of the sorbitol biosensor systems using a spectrometer and a PMT was 5.0-1000 µmol L −1 and 1.0-1000 µmol L −1 , respectively. The sorbitol biosensor system using the sorbitol dehydrogenase from microorganisms of the genus Flavimonas has high selectivity and sensitivity compared with that from sheep liver. The sorbitol biosensor allows for point-of-care testing applications or daily health care tests for diabetes patients.

Immobilized Enzymes in Biosensor Applications

“…The optical transducer can monitor either the absorption change at 340–360 nm, or the fluorescence emission change at 450 nm, and the signal is then correlated to the concentration of the target analytes. Biosensors built on this principle have been developed for the monitoring of glucose, cholesterol or l -amino acids [97], glucose-6-phosphate [98], sorbitol [99], glutamate [100], pyruvate or l -lactate. In a different approach, a fluorescent inhibitor is used to specifically bind to an enzyme in the presence of a specific cofactor.…”

Fiber-Optic Chemical Sensors and Biosensors (2015–2019)

“…A FOBS for sorbitol was constructed by immobilizing sorbitol dehydrogenase on an optical fiber. 329 In the presence of NAD + , the enzymatic oxidation of sorbitol leads to a reduction of NAD + to form blue fluorescent NADH. Sorbitol can be assayed in the 1.0−1000 μM concentration range.…”

Fundamentals and commercial aspects of nanobiosensors in point-of-care clinical diagnostics

“…The major benefit offered by a fluorescence-based biosensors is their greater selectivity as every molecule shows its characteristic fingerprint spectrum (Strianese et al 2012). For instance, the conversion of NAD + to NADH was employed to detect a diabetic biomarker sorbitol, where the fluorescence intensity of NADH is correlated with the quantification of sorbitol (Gessei et al 2015) (The schematic representation has been shown in Fig. 3b).…”