• Journal of Sensor Science and Technology
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• v.17 no.4
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• pp.250-255
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• 2008

A vanadium pentoxide ($V_2O_5$)-based bolometric infrared (IR) sensor has been designed and fabricated using micro electro mechanical systems (MEMS) technology for glucose detection and its resistive characteristics has been illustrated. The proposed bolometric infrared sensor is composed of the vanadium pentoxide array that shows superior temperature coefficient of resistance (TCR) and standard silicon micromachining compatibility. In order to achieve the best performance, deposited $V_2O_5$ thin film is optimized by adequate rapid thermal annealing (RTA) process. Annealed vanadium oxide thin film has demonstrated a linear characteristic and relatively high TCR value (${-4}%/^{\circ}C$). The resistance of vanadium oxide is changed by IR intensity based on glucose concentration.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.415-420
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• 1999

A biochemical oxygen demand (BOD) sensor loaded with Candida sp. was designed and constructed for the quick measurement of the concentrations of biologically assimilable organic substances dissolved in water. The sensitivity of the sensor was higher for glucose, acetic acid, aspartic acid and glutamic acid than that for lactose, sucrose and lactic acid. The sensitivities of BOD sensors loaded with $Zn^{2+}$ tolerant and intact strains were almost identical while the sensitivity of sensor loaded with Cd$^{2+}$ tolerant strain was considerably lower. The sensitivities of the sensors loaded with intact or $Zn^{2+}$ tolerant strains did not change with the concentration of $Cd^{2+}$ in the aqueous solution while the sensitivity of the sensor loaded with $Cd^{2+}$ tolerant strain decreased slightly. The sensitivities of the sensors loaded with intact strain, $Zn^{2+}$ or $Cd^{2+}$ tolerant strains were not affected by the concentration of $Zn^{2+}$ in the aqueous solution.n.

• Journal of Sensor Science and Technology
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• v.25 no.6
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• pp.435-439
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• 2016

We report a novel detection technology for glycated hemoglobin (HbA1c) that is measured primarily to identify the three-month average plasma glucose concentration. In enzymatic measuring of glycated hemoglobin, the generated hydrogen peroxide was then used as a reducing agent of gold (III) for the synthesis of gold (0). Gold nanoparticles obtained from this novel approach were measured by optical and piezoelectric methods. In optical method, we have developed polymer based film-type sensor cartridge filled with all the reagents for glycated hemoglobin analysis and the cartridge worked very well having the detection limit of 0.53% of glycated hemoglobin. On the other hand, quartz crystal microbalance (QCM) sensors also have been developed to determine the abilities of surface modified QCM sensors at various levels of the concentration of glycated hemoglobin to bind gold nanoparticles and limit of detection was 0.90%. Finally, despite of relatively lower sensitivities of QCM sensor and film-type optical sensor than well-plate based optical detection, these two sensors were available to measure the glycated hemoglobin level for diabetes patients and normal person.

• Journal of Digital Policy
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• v.1 no.2
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• pp.61-69
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• 2022

The paper is a study to develop and verify a blood glucose level prediction model based on biosignals obtained from photoplethysmography (PPG) sensors, ICT technology and data. Blood glucose prediction used the MLP architecture of machine learning. The input layer of the machine learning model consists of 10 input nodes and 5 hidden layers: heart rate, heart rate variability, age, gender, VLF, LF, HF, SDNN, RMSSD, and PNN50. The results of the predictive model are MSE=0.0724, MAE=1.1022 and RMSE=1.0285, and the coefficient of determination (R²) is 0.9985. A blood glucose prediction model using bio-signal data collected from digital devices and machine learning was established and verified. If research to standardize and increase accuracy of machine learning datasets for various digital devices continues, it could be an alternative method for individual blood glucose management.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.72-73
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• 1998

A new method for enzyme immobilization has been developed to remove interference by potential interferents in body fluids. Instead of using electron mediators, we chose direct hydrogen peroxide measurement route. Extremely hydrogen peroxide-selective polymer was coated as an inner membrane to exclude interferents and then glucose oxidase(GOx) was entrapped by electropolymerization of inert monomers. There was no solvent casting step throughout the whole fabrication procedure but all membranes on Pt-Ir electrode were formed by electropolymerization. Thus, membrane thickness, quantity of enzyme loaded and can be controlled by electrochemical parameters. As a result, reproducibility of biosensor characteristics becomes remarkably improved in terms of mass production.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1412-1415
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• 2008

A glucose biosensor using a microdisk resonator in polymeric waveguides was developed by observing either the shift in the resonant wavelength or the variation in the optical power. The deformation in the transfer curve of the vertically coupled resonator sensor resulting from the variation in the disk-to-ring coupling, which was incurred by the application of the target analyze, was suppressed. And the refractive index of the polymeric waveguide was devised to closely follow that of the analyze itself for enhancing the sensitivity of the sensor. The sensitivity and measurement range were observed to be respectively 0.14 pm/(mg/dL) and 1500 mg/dL (theoretically up to 4700 mg/dL, for the wavelength shift method and 0.04 dB/(mg/dU and 140 mg/dL the power variation scheme.

• Journal of Computing Science and Engineering
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• v.10 no.3
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• pp.75-84
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• 2016

Medical cyber-physical systems (MCPS) integrate sensors, actuators, and software to improve patient safety and quality of healthcare. These systems introduce major challenges to safety analysis because the patient's physiology is complex, nonlinear, unobservable, and uncertain. To cope with the challenge that unidentified physiological parameters may exhibit short-term variances in certain clinical scenarios, we propose a novel run-time predictive safety monitoring technique that leverages a maximal model coupled with online training of a computational virtual subject (CVS) set. The proposed monitor predicts safety-critical events at run-time using only clinically available measurements. We apply the technique to a surgical glucose control case study. Evaluation on retrospective real clinical data shows that the algorithm achieves 96% sensitivity with a low average false alarm rate of 0.5 false alarm per surgery.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1100-1103
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• 2003

One of the good ways to raise the rate of the electrochemical reaction is to broaden the effective surface area of the electrode by developing cylindrical nano-pores on the surfaces. The numerous pores of several nanometer in diameter can be used to enhance a specific faradaic reaction so that the nano-porous structure attract keen attention in terms of implication of new bio/chemical sensors, in which no chemical modification is involved. Amperometric glucose sensor is a representative example that needs the selective enhancement of glucose oxidation over the current due to physiological interferents such as ascorbic acid. The present paper reports how the ascorbic acid and glucose diffuse around the nano-porous surface by simulation study, for which 2D-FDM (Finite Difference Method) was adopted. The results of the simulation not only consist with those from electrochemical experiments but also reveal valuable potential for more advanced application of the nano-porous electrode.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.35-39
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• 2011

A disposable electrochemical immunosensor system has been developed for the detection of herbicide in aqueous samples. Disposable screen printed carbon electrodes(SPCE) were used as basic electrodes and an enzyme, horseradish peroxidase (HRP), and anti-herbicide antibodies was immobilised on to the working electrode of SPCE by using avidin-biotin coupling reactions. An herbicide-glucose oxidase conjugates have been used for the competitive immunoreaction with sample herbicides. The enzymatic reaction between the conjugated glucose oxidase and glucose added generates hydrogen peroxide, which was reduced by the peroxidase immobilised. The latter process caused an electrical current change, due to direct re-reduction of peroxidase by a direct electron transfer mechanism, which was measured to determine the herbicides in the sample. The optimal operational condition was found to be: $20\;{\mu}gl-1$ deglycosylated avidin loading to the working electrode and working potential +50 mV vs. Ag/AgCl. The total assay time was 15 min after sample addition. The detection limits for herbicides, atrazine and simazine, were found to be 3 ppb and 10 ppb, respectively.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.37-38
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• 2006

Conjugated diacetylene supramolecules are interesting biomimetic materials in view of application to chemical and label-free biological sensors. These supramolecules are unique in changing color from blue to red upon specific binding events. Various binding events including viruses, toxins, glucose, and ionic interactions have been reported detectible. Here, we focus on fabrication of polydiacetylene supramolecule dot array patterns on solid substrates by using a conventional microarrayer. Each dot is found to possess the color-changing property as well as the fluorescence self-emission. This technique allows us, for the first time, to fabricate biochips based on polydiacetylene supramolecules. Label-free detection of small molecules and biological targets will be discussed.