Ex-vivo glucose sensors using micro-dialysis: importance of on-line recovery rate determination by multi-analyte infrared spectrometry

Abstract

Micro-dialysis has been established in the clinical environment for continuously harvesting body fluids, but a drawback of this process are variable recovery rates, which can be observed especially for subcutaneously implanted catheters. Perfusates with either acetate or mannitol have been investigated as recovery markers. The latter substance is suggested for application with external cavity tuneable quantum cascade lasers, rendering a limited wavenumber interval in contrast to FTIR-spectrometers. Despite the overlap of mannitol and glucose spectra, their simultaneous quantification was successful. By investigating the depletion of the marker substances from the perfusates using different micro-dialysis devices, the theoretical nonlinear relationship between the relative dialysate marker concentration and glucose recovery rate was confirmed for the marker substance-analyte pair of acetate and glucose, rendering a basis for reliable blood glucose measurements. For the pair of mannitol and glucose an almost linear dependency was expected for the microdialysate catheters and experimentally verified, which provides a straightforward correction of any dialysis recovery rate variation during patient monitoring.

A possible Fourier transform infrared‐based plasma fingerprint of angiotensin‐converting enzyme inhibitor‐induced reversal of endothelial dysfunction in diabetic mice

“…The observed bands were labelled and presented in a band assignment table (Table ). FTIR spectroscopy was successfully employed in the quantification of glucose in various bodily fluids and we confirmed unequivocal detection of hyperglycemia by FTIR in our plasma samples. However, for further analysis we chose samples of plasma from db/db and PER‐treated animals with the similar level of HbA1c to find changes induced by PER in FTIR spectra of plasma, that are not related directly to hyperglycemia.…”

“…According to reports showing the quantification of glucose in serum, plasma and blood by means of FTIR spectroscopy , we chose the IR bands at 1033 and 1079 cm −1 as glucose markers, and an increase in their intensity in diabetes is clearly visible in the insets in Figure A,B. The spectral region of 1200 to 950 cm −1 is also specific for carbohydrates; however, absorbances of bands present in this range do not change in the way observed for 1033 and 1079 cm −1 maxima.…”

“…Both drugs are prescribed for the glycemic control and similarly to the previous report on metformin‐treated rats , the combination therapy was more effective than the treatment by gliclazide alone as regards changes in the spectral regions of proteins and glucose. In fact, a growing interest on the application of FTIR spectroscopy has been focused on the fast and reagent‐free quantification of glucose in blood, urea, serum and saliva with a special emphasis on the development of a noninvasive technique for continuous monitoring of blood glucose .…”

Monitoring Neurochemistry in Traumatic Brain Injury Patients Using Microdialysis Integrated with Biosensors: A Review

“…Advantageously, this biosensor quantified other small molecules including glycerol. Since then, numerous biosensors coupled to microdialysis for the quantification of molecules found in body fluids, tissues, and organs other than the brain have been reported [ 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ]. An earlier review of biochemical monitoring of various bodily fluids has been presented elsewhere [ 79 ].…”

“…Various applications of optical sensing have been performed both in a label-free or label-based manner. For label-based detection, the optical signal is acquired by fluorescent or colorimetric techniques [ 95 , 96 , 97 , 98 ], whereas label-free techniques involve light–analyte interactions to facilitate signal detection exemplified by spectroscopic biosensors [ 49 , 64 , 65 , 66 , 67 , 68 , 69 , 99 ]. Other than the widely used offline ISCUSflex colorimetric bedside analyser, all optical based techniques integrated with microdialysis to quantify TBI metabolites have utilised infrared spectroscopic sensors.…”