• KSBB Journal
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• v.20 no.3
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• pp.197-204
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• 2005

Lab-on-a-chip is a miniaturized analytical device in which all of the procedures for the analysis of molecules are carried out, such as pretreatment, reaction, separation, detection, etc. Lab-on-a-chip has increasing concern as a device not only for rapid detection of molecules but also for high throughput screening and point of care, because conventional laborious and time consuming analytical procedures can be substituted. Thus, a lot of microfabrication and analytical techniques for lab-on-a-chip have been developed with microstructures smaller than a few hundreds of micrometers. Separation of the molecules is one of the most important components of lab-on-a-chip, because effective separation method can simplify the design and can provide better sensitivity. The electrokinetic separation based on capillary electrophoresis is most widely employed technique in lab-on-a-chip for the control of fluids and the separation of molecules. In this article, bioseparation techniques and its applications realized in lab-on-a-chip are reviewed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.18-23
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• 2022

Electrohydrodynamic jet (e-jet) printing, a type of direct contactless microfabrication technology, is a versatile fabrication process that enables a wide range of micro/nanopattern arrays by applying a strong electric field between the nozzle and the substrate. In general, the morphology and the thickness of polymers/quantum dot micropatterns show a systematic dependence on the diameter of the nozzle and the ink composition with a fully automated printing machine. The purpose of this report is to provide typical examples of e-jet printed micropatterns of polymers/quantum dots to explain the effect of each process variable on the result of experiments. Here, we demonstrate several operating conditions that allow high-resolution printing of layers of polymers/quantum dots with a precise control over thickness and submicron lateral resolution.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.404-413
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• 2023

In this research, we studied the development of a SUS304 microneedle array based on microfabrication technology and the applicability of Parylene-C thin film, a medical polymer material. First of all, four materials commonly used in the field of medical engineering (SUS304, Ti, PMMA, and PEEK) were selected and a 5 ㎛ Parylene-C thin film was deposited. The applicability of Parylene-C coating to each material was confirmed through SEM analysis, contact angle measurement, surface roughness(Ra) measurement, and adhesion test according to ASTM standards for each specimen. Parylene-C thin film was deposited based on chemical vapor deposition (CVD), and a 5 ㎛ Parylene-C deposition process was established through trial and error. Through characteristic experiments to confirm the applicability of Parylene-C, SUS304 material, which is the easiest to apply Parylene-C coating without pretreatment was selected to develop a microneedle array based on CNC micromachining technology. The CNC micromachining process was divided into a total of 5 steps, and a microneedle array consisting of 19 needles with an inner diameter of 200 ㎛, an outer diameter of 400 ㎛, and a height of 1.4 mm was designed and manufactured. Finally, a 5 ㎛ Parylene-C coated microneedle array was developed, which presented future research directions in the field of microneedle-based drug delivery systems.

• Science of Emotion and Sensibility
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• v.14 no.1
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• pp.157-164
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• 2011

Emotion science is one of the rapidly expanding engineering/scientific disciplines which has a major impact on human society. Such growing interests in emotion science and engineering owe the recent trend that various academic fields are being merged. In this paper we propose the potential importance of the biochip technology in which the human emotion can be precisely measured in real time using body fluids such as blood, saliva and sweat. We firstly and newly name such a biochip an Emotion-On-a-Chip (EOC). EOC consists of biological markers to measure the emotion, electrode to acquire the signal, transducer to transfer the signal and display to show the result. In particular, microfabrication techniques made it possible to construct nano/micron scale sensing parts/chips to accommodate the biological molecules to capture the emotional bio-markers and gave us a new opportunities to investigate the emotion precisely. Future developments in the EOC techniques will be able to help combine the social sciences and natural sciences, and consequently expand the scope of studies.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.55-59
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• 2018

In this paper, we investigated the characteristics of shear stress type piezoresistor on a diaphragm structure formed by MEMS (Microelectromechanical System) technology of silicon-direct-bonding (SDB) wafers with Si/$SiO_2$/Si-sub. The diaphragm structure formed by etching the backside of the wafer using a TMAH aqueous solution can be used for manufacturing various sensors. In this study, the optimum shape condition of the shear stress type piezoresistor formed on the diaphragm is found through ANSYS simulation, and the diaphragm structure is formed by using the semiconductor microfabrication technique and the shear stress formed by boron implantation. The characteristics of the piezoelectric resistance are compared with the simulation results. The sensing diaphragm was made in the shape of an exact square. It has been experimentally found that the maximum shear stress for the same pressure at the center of the edge of the diaphragm is generated when the structure is in the exact square shape. Thus, the sensing part of the sensor has been designed to be placed at the center of the edge of the diaphragm. The prepared shear stress type piezoresistor was in good agreement with the simulation results, and the sensitivity of the piezoresistor formed on the $2200{\mu}m{\times}2200{\mu}m$ diaphragm was $183.7{\mu}V/kPa$ and the linearity of 1.3 %FS at the pressure range of 0~100 kPa and the symmetry of sensitivity was also excellent.