Determination of human blood glucose levels using microchip electrophoresis

Abstract

Determination of human blood glucose levels using microchip electrophoresisA high-performance monitoring system for human blood glucose levels was developed using microchip electrophoresis with a plastic chip. The combination of reductive amination as glucose labeling with fluorescent 2-aminoacridone (AMAC) and glucose-borate complex formation realized the highly selective detection of glucose even in a complex matrix such as a blood sample. The migration time of a single peak, observed on an electropherogram of AMAC-labeled plasma, closely resembled that of glucose standard solution. The treatment of plasma with hexokinase or glucokinase for glucose phosphorylation resulted in a peak shift from approximately 145 to 70 s, corresponding to glucose and glucose-6-phosphate, respectively. A double-logarithm plot revealed a linear relationship between glucose concentration and fluorescence intensity in the range of 1-300 mM of glucose (r 2 = 0.9963; p ,0.01), and the detection limit was 0.92 mM. Furthermore, blood glucose concentrations estimated from the standard curves of three subjects were compared with results obtained by conventional colorimetric analysis using glucose dehydrogenase. Good correlation was observed between methods according to simple linear regression analysis (p ,0.05). The reproducibility of the assay was about 6.3-9.1% (RSD) and the within-days and between-days reproducibility were 1.6-8.4 and 5.2-7.2%, respectively. This system enables us to determine blood glucose with high sensitivity and accuracy, and will be applicable to clinical diagnosis.

Highly Sensitive Detection of Monosaccharides on Microchip Electrophoresis Using pH Discontinuous Solution System

“…The LOD for Glc was 0.92 μM in Ref. 12. The LOD of amino monosaccharides GlcNAc and GalNAc were decreased by a factor of 65.9 and 44.4, respectively, using the pH discontinuous solution system.…”

“…A conventional running buffer [11][12][13] including cellulose polymer additives was prepared by adding MC to 200 mM boric acid and stirring slowly until the solution appeared to be homogeneous and transparent. 18 Apparatus A mixture of monosaccharides was separated into each component using a PMMA microchip (i-chip 3 DNA, Hitachi Chemical, Tokyo) and an MCE machine (SV1100 Microchip CE system, Hitachi, Tokyo).…”

“…[3][4][5] This technique has been successfully used to analyze DNA fragments, 6 aminoacids, 7 proteins, 8,9 and carbohydrates. [10][11][12][13] However, a mixture of either neutral or amino monosaccharides is difficult to separate into its components by conventional electrophoresis because of their similarities in structure, molecular weight, and electric charge. 11 We have reported a conformational separation technique for monosaccharides in polymer microchips.…”

“…The technique has been used for many applications. 12,13 However, the sensitivity of conformational separation is inferior to that of conventional capillary electrophoresis (CE).…”

Accurate quantitation of salivary and pancreatic amylase activities in human plasma by microchip electrophoretic separation of the substrates and hydrolysates coupled with immunoinhibition

“…Separation was successfully performed considering the difference in the stability of the complex between the hydroxyl residues of a monosaccharide and the borate ions in 0.2 M borate buffer (pH 8.5) [36]. Human blood glucose has been correctly determined on conformational separation by microchip electrophoresis [38]. We therefore employed this conformational separation method in which a fluorescence-labeled oligosaccharide was used as a substrate for amylase with or without anti-S-AMY mAb for microchip electrophoresis for the detection of human blood isoamylase.…”