• Journal of Life Science
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• v.23 no.9
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• pp.1104-1108
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• 2013

Ethylene glycol (EG) is the most commonly used for automotive antifreeze, and it's easily misuseful for human. EG poisoning occurs in suicide attempts and infrequently, either intentionally through misuse or accidentally because of sweet taste. Though EG itself is mild toxic to the human body, it becomes higher toxic organic acids by in vivo broken down that are responsible for extensive cellular damage in various tissues caused principally by the metabolites. It is already well known that various cellular stresses induce gene expression of endoplasmic reticulum (ER) chaperones and ER stress sensors. This study demonstrated that regulation of gene expression of ER chaperones and ER stress sensors was induced by EG in rat tissues, and in tissues histological changes are also detected by both staining H&E and immunofluorescent.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.403-411
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• 2023

The shift in the medical paradigm from treatment to prevention and diagnosis has underscored the growing significance of biosensors. Notably, the recent COVID-19 pandemic has spurred the widespread adoption of biosensors for the detection of viral genes and antigens. Consequently, there has been a substantial increase in both the demand for biosensors and the industries associated with their production. Furthermore, biosensors find applications not only in healthcare but also in diverse fields such as environmental monitoring, food quality control, military defense, and industrial processes. In this brief review, we delve into the essential attributes of biosensors, namely sensitivity, selectivity, and stability. We provide an overview of the latest research trends aimed at improving these attributes. Additionally, we introduce recent research cases in which these attributes are being applied both in vivo and in vitro.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.3
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• pp.38-47
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• 1995

A new automatic cardiac output control algorithm for the motor-driven electromechanical total artificial heart(TAH) was developed based on the motor current waveform analysis without using any extra transducer. The basic control requirements of artificial heart can be described in terms of three features : preload sensitivity, afterload insensitivity, and balanced ventricular outputs. In the previous studies, many transducers were utilized to obtain informations of hemodynamic states for the automatic cardiac output control, But such automatic control systems with sensors have had reliability problems. We proposed a new sensorless automatic cardiac output control algorithm providing adequate cardiac output to the time-varying physiological demand without causing right atrial collapse, which is one of the critical problem in an active-filling type device. In-vitro tests were performed on a mock circulation system to evaluate the performance of the developed algorithm and the results show that the new algorithm satisfied the basic control requirements on the cardiac output response and the possibility of application of the developed algorithm to in vivo experiments.

• Journal of Sensor Science and Technology
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• v.23 no.6
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• pp.409-415
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• 2014

We had presented an inductive type intraocular pressure sensor (L-sensor) in previous work. The distance between a micro coil and a ferrite on the membrane was modulated by pressure, and as a result the inductance and resonant frequency were changed. However, L-sensor has some problems to implant in eyes. First problem is low sensitivity. When L-sensor was implanted in rabbit's eyes, resonant frequency of L-sensor was very hard to detect. Second problem is biocompatibility. Size of L-sensor is $6{\times}7{\times}1.2mm$. When L-sensor was implanted in the eyes, it caused the inflammation. Therefore, this study suggests an inductive and capacitive type IOP sensor (LCsensor). The sensitivity of the LC-sensor 27.3 kHz/mmHg under 60mmHg. It is much larger than 14 kHz/mmHg of the L-sensor. And the size of LC-sensor is 47% smaller than L-sensor. After 2 weeks from the implantation of LC-sensor into rabbit eyes, we measured the changes of resonant frequency of LC-sensor according to increased IOP by Balanced Salt Solution (BSS) injection. As a result, the sensitivity of LC-sensor in in vivo test is 25 kHz/mmHg. That is similar to the sensitivity of in vitro test.

• Journal of Sensor Science and Technology
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• v.14 no.4
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• pp.211-218
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• 2005

As the cause and the treatment about gastrointestinal disease has been issued recently, the importance of measuring the pressure in the gastrointestinal tract has been increased. However, the conventional measurement methods of the pressure in the gastrointestinal tract cause the patients' pain and inconvenience as well as an inaccurate pressure measurement. In this paper, the pressure monitoring telemetry system has been designed and implemented for an accurate pressure measurement inside the gastrointestinal tract with minimizing pain and inconvenience. The pressure monitoring telemetry system is composed of a pressure measurement capsule and an external receiver. The capsule has been miniaturized into the same size of a vitamin tablet so that the capsule can be swallowed through the oral cavity. After the capsule acquires and encodes the pressure data in the gastrointestinal tract, the encoded pressure data are modulated by frequency shift keying (FSK) and transmitted with ultrahigh frequency (UHF) band signal to the outside of a body. The performance of the telemetry capsule for monitoring pressure in the gastrointestinal tract is demonstrated by the results of animal in-vivo experiments.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1627-1628
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• 2006

In this paper, mesoporous only platinum electrode and micro pore platinum electrode with mesoporous Pt are fabricated and characterized on a silicon substrate to check their usability as enzymeless sensing electrodes for developing non-disposable glucose sensors integrated with silicon CMOS read out circuitry. Since most of electrochemical glucose sensors are disposable due to the use of the enzymes that are living creatures, these are limited to use in the in-vivo and continuous monitoring system applications. The proposed mesoporous Pt electrode with approximately 2.5nm in pore diameter and 150nm in height was fabricated by using a nonionic surfactant $C_{16}EO_8$ and an electroplating technique. The micro pore Pt electrode with mesoporous Pt means the mesoporous Pt electrode fabricated on top of micro pore arrayed Pt electrode with approximately $10{\mu}m$ in pore diameter and $80{\mu}m$ in height. The measured current responses at 10mM glucose solution of plane Pt, micro pore Pt, micro pore with mesoporus Pt, and mesoporous Pt electrodes are approximately $9.9nA/mm^2$, $92.4nA/mm^2$, $3320nA/mm^2$ and $44620nA/mm^2$, respectively. These data indicate that the mesoporous Pt electrode is much more sensitive than the other Pt electrodes. Thus, it is promising for non-disposable glucose sensor and electrochemical sensor applications.

• Journal of Sensor Science and Technology
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• v.24 no.1
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• pp.22-28
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• 2015

This study demonstrates a polyimide nerve cuff electrode with a conductive polymer for improving recording signal quality at peripheral nerve. The nerve cuff electrodes with platinum (Pt), iridium oxide (IrOx), and poly(3,4-ethylenedioxythiophene): p-toluene sulfonate (PEDOT:pTS) were fabricated and investigated their electrical characteristics for improving recorded nerve signal quality. The fabricated nerve cuff electrodes with Pt, IrOx, and PEDOT:pTS were characterized their impedance and CDC by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The impedance of PEDOT:pTS measured at 1 kHz was $257{\Omega}$, which was extremely lower than the value of the nerve cuff electrodes with IrOx ($15897{\Omega}$) and Pt ($952{\Omega}$), respectively. Furthermore, the charge delivery capacity (CDC) of the nerve cuff electrode with PEDOT:pTS was dramatically increased to 62 times than the nerve cuff electrode with IrOx. In ex-vivo test using extracted sciatic nerve of spaque-dawley rat (SD rat), the PEDOT:pTS group exhibited higher signal-to-interference ratio than IrOx group. These results indicated that the nerve cuff electrode with PEDOT:pTS is promising for effective implantable nerve signal recording.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.148-155
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• 2001

A pressure sensor on the tip of a catheter which is utilized to measure the in-vivo pressure in a human body was fabricated and the characteristic of the pressure sensor as measured. To fit into a catheter with 1 mm caliber, samples of $150\;{\mu}m$(thickness) ${\times}$ (600, 700, 800, 900, 1000) ${\mu}m$(width) ${\times}2\;mm$(length) was fabricated. The thicker face with $450\;{\mu}m$ thickness of SDB wafer was made thin to $134\;{\mu}m$ thickness using KOH etchant and it made possible to fabricate sensor cell with the width shorter than 1 mm. Different to the whitstone bridge sensor, we formed one piezoresistor and one reference resistor in sensor. Therefore there are possibilities of reduction of the sensitivity, then by using the simulation tool ANSYS 5.5.1, the location and the type of the piezoresistor was optimized. Another piezoresistor type of sensor which contain one longitudinal and one transverse piezoresistor was fabricated at the same time, but the sensitivity was not improved very much. To get the output versus the pressure, a constant current source and a implementation amplifier was used. As a result, the maximum sensitivity of the sensor with one piezoresistor was $1.6\;{\mu}V/V/mmHg$.

• Journal of Sensor Science and Technology
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• v.18 no.2
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• pp.122-127
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• 2009

We have developed and reported several micro-spikes for minimally invasive biopsy. In this paper, a micro-tissue collecting tool for tissue diagnosis extracted by micro-spike is presented. Using proposed polydimethy-siloxane (PDMS) micro-tissue collecting tool, which has a negative micro-spike structure in a porous chamber, the extracted tissue in a micro-spike is effectively detached. The gastro-intestinal tissue of a pig is extracted in an in vivo environment, and then it is detached from a micro-spike using the PDMS micro-tissue collecting tool. A fine clinical picture of the detached tissue is acquired.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.309-314
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• 2013

Glass micropipettes are widely used for drug injection in neurological studies. To enable these devices to monitor neural activity simultaneously with drug injection, an electrode such as Ag/AgCl must be located near or inserted into the glass micropipette to detect electrical signals in vivo. Here, we report carbon-nanotube-modified glass micropipettes (CNGs), which have excellent electrochemical properties such as low impedance and large electrochemical surface area suited for neural recording. In addition, using a standard pressure pump, CNGs can deliver drugs to the target region without bending. Because they are based on standard glass micropipettes, CNGs can readily be applied to traditional equipment, creating opportunities to monitor precisely the drug-injected area.