• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.371-378
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• 1998

Pesticide has played important role in Korean and Austrailian agriculture. In addition, pesticides are the most reliable tools pests in agriculture. Recently, it is highly recommended that the use of pesticide should be concerned with both atricultural and environmental aspect, also legislation on environmental contamination has been fortified to the world. Particularly, the attention on agrochemicals has been focused on the soil abuse and the water contamination at present time. In spite of this kind of concern, a few research about pesticides using in Australia and Korean have been conducted to their behaviors under australian and korean environment to avoid environmental contamination by pesticides. Thus, the research organizations need facilities to analyze the characteristics of each pesticide and the environmental fate of pesticides. The conventional analytical method to detect pesticides and their metabolites can not be overcome to reduce time, expenditure, and complexity of analysis even though the methods are accurate and precise. For example, High performance liquid chromatography(HPLC), and gas chromatography (GC) used until now are less choice detectors and often lower sensitive. In contrast to the conventional analytical methods, biosensors are so fast in analysis and has high productivity and analyze multi=sample simultaneously. Therefore, it is biosensing analytical method that we could consider as an alternative method intead of the conventional methods.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.69-75
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• 2012

Five-channel electrochemical chips were fabricated based on the Micro-electromechanical System (MEMS) technology and were used as platforms to develop DNA arrays. Different kinds of thiolated DNA strands, whose sequences were related to white spot syndrome virus (WSSV) gene, were separately immobilized onto different working electrodes to fabricate a combinatorial biosensor system. As a result, different kinds of target DNA could be analyzed on one chip via a simultaneous recognition process using potassium ferricyanide as an indicator. To perform quantitative target DNA detection, a limit of 70 nM (S/N=3) was found in the presence of 600 nM coexisting noncomplementary ssDNA. The real samples of loop-mediated isothermal amplification (LAMP) products were detected by the proposed method with satisfactory result, suggesting that the multichannel chips had the potential for a high effective microdevice to recognize specific gene sequence for pointof-care applications.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.373-377
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• 2003

Various groups of industrial and agricultural pollutants (heavy metal ions, cyanides, and pesticides) can be detected by enzymes. Since heavy metal ions inhibit urease, cyanides inhibit peroxidase, organophosphorus and carbamate pesticides inhibit butyrylcholinesterase, these enzymes were co-immobilized into a bovine serum albumin gel on the surface of an ion-sensitive field effect transistor to create a bioprobe that is sensitive to the compounds mentioned above. The sensitivity of the present sensor towards KCN corresponded to $1\;\mu\textrm{M}$ with 1 min of incubation time. The detection limits for Hg(II) ions and the pesticide carbofuran were 0.1 and $0.5\;\mu\textrm{M}$, respectively, when a 10 min sensor incubation time in contaminated samples was chosen. The total time for determining the concentrations of all species mentioned did not exceed 20 min.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.103-112
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• 2009

Neuron-on-a-Chip technology is based on advanced neuronal culture technique, surface micropatterning, microelectrode array technology, and multi-dimensional data analysis techniques. The combination of these techniques allowed us to design and analyze live biological neural networks in vitro using real neurons. In this review article, two underlying technologies are reviewed: Microelectrode array technology and Neuronal patterning technology. There are new opportunities in the fusion of these technologies to apply them in neurobiology, neuroscience, neural prostheses, and cell-based biosensor areas.

• Vacuum Magazine
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• v.2 no.1
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• pp.10-16
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• 2015

With the recognition of nanotechnology as one of the future strategic technologies, the R&D efforts have been performed under exclusive supports of governments and private sectors. At present, nanotechnology is at the focus of research and public attention in almost every advanced country including USA, Japan, and many others in EU. Keeping tracks of such technical trends, center for nanoscale mechatronics and manufacturing (CNMM) was established in 2002 as a part of national nanotechnology promotion policy led by ministry of science and technology (MOST) in Korea. It will hold widespread potential applications in electronics, optical electronics, biotechnology, micro systems, etc, with the promises of commercial visibility and competitiveness. In this paper, wafer scale multilayer nanoimprint lithography technology which is well-known the next generation lithography, roll-typed nanoimprint lithography (R-NIL), roll-typed liquid transfer imprint lithography (R-LTIL), the key technology for nanomanufacturing and nanoscale measurement technology will be introduced. Additionally, its applications and some achievements such as solar cell, biosensor, hard disk drive, and MOSFET, etc by means of the developed multilayer nanoimprint lithography system are introduced.

• KSBB Journal
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• v.15 no.5
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• pp.497-500
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• 2000

Liposomes and proteoliposomes, artificial membranes, can interact with many solutes, such as drugs, peptides and proteins. The immobilization of (prot대)liposomes as supramolecular aggregates on gold surfaces have potential applications in nano and biosensor technology. We demonstrated a quartz crystal analyzer (QCA) based method to monitor the construction of multi-layers of unilamellar liposomes based on avidin-biotin binding on gold surfaces using a quartz crystal microbalance (QCM). Thus, the QCA provides an on line and efficient method of detecting the construction of protein membranes, which has applications in biosensing systems.

• BioChip Journal
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• v.12 no.4
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• pp.268-279
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• 2018

Flower-shaped organic-inorganic hybrid nanostructures, termed nanoflowers, have received considerable recent attention as they possess greatly enhanced activity, stability, durability, and even selectivity of entrapped organic biomolecules, which are much better than those from the conventional methods. They can be synthesized simply via co-incubation of organic and inorganic components in aqueous buffer at room temperature and yield hierarchical nanostructures with large surface-to-volume ratios, allowing for low-cost production by easy scale-up, as well as the high loading capacity of biomolecules without severe mass transfer limitations. Since a pioneering study reported on hybrid nanoflowers prepared with protein and copper sulfate, many other organic and inorganic components, which endow nanoflowers with diverse functionalities, have been employed. Thanks to these features, they have been applied in a diverse range of areas, including biosensors and biocatalysis. To highlight the progress of research on organic-inorganic hybrid nanoflowers, this review discusses their synthetic methods and mechanisms, structural and biological characteristics, as well as recent representative applications. Current challenges and future directions toward the design and development of multi-functional nanoflowers for their widespread utilization in biotechnology are also discussed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.141-146
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• 2017

In this letter, we propose the use of tunneling field effect transistors (TFET) as a biosensor that detects bio-molecules on the gate oxide. In TFET sensors, the charges of target molecules accumulated at the surface of the gate oxide bend the energy band of p-i-n structure and thus tunneling current varies with the band bending. Sensing parameters of TFET sensors such as threshold voltage ($V_t$) shift and on-current ($I_D$) change are extracted as a function of the charge variation. As a result, it is found that the performances of TFET sensors can surpass those of conventional FET (cFET) based sensors in terms of sensitivity. Furthermore, it is verified that the simultaneous sensing of two different target molecules in a TFET sensor can be performed by using the ambipolar behavior of TFET sensors. Consequently, it is revealed that two different molecules can be sensed simultaneously in a read-out circuit since the multi-sensing is carried out at equivalent current level by the ambipolar behavior.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2387-2392
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• 2009

A composite film of multi-walled carbon nanotube (MWCNT)/sol-gel-derived zinc oxide(ZnO)/Nafion has been utilized as an efficient immobilization matrix for the construction of a highly sensitive and stable tris(2,2'-bipyridyl) ruthenium(II) (Ru(${bpy)_3}^{2+})$ electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behaviors of Ru(${bpy)_3}^{2+})$ ion-exchanged into the composite film were strongly dependent upon the sol-gel preparation condition, the amount of MWCNT incorporated into the ZnO/Nafion composite film, and the buffer solution pH. The synergistic effect of MWCNTs and ZnO in the composite films increased not only the sensitivity but also the long-term stability of the ECL sensor. The present ECL sensor based on the MWCNT/ZnO/Nafion gave a linear response ($R^2$ = 0.999) for tripropylamine concentration from 500 nM to 1.0 mM with a remarkable detection limit (S/N = 3) of 15 nM. The present ECL sensor showed outstanding long-term stability (94% initial signal retained for 5 weeks). Since the present ECL sensor exhibits large response towards NADH, it could be applied as a transduction platform for the ECL biosensor in which the NADH is produced from the dehydrogenase-based enzymatic reaction in the presence of NA$D^+$ cofactor.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.684-689
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• 2021

In this paper, we develop a cost effective and disposable voltammetric sensing platform involving screen-printed carbon electrode (SPCE) modified with the nanocomposites composed of multi-walled carbon nanotubes, polyelectrolyte, and tyrosinase for bisphenol A. This is known as an endocrine disruptor which is also related to chronic diseases such as obesity, diabetes, cardiovascular and female reproductive diseases, precocious puberty, and infertility. A negatively charged oxidized multi-walled carbon nanotubes (MWCNTs) wrapped with a positively charged polyelectrolyte, e.g., polydiallyldimethylammonium, was first wrapped with a negatively charged tyrosinae layer via electrostatic interaction and assembled onto oxygen plasma treated SPCE. The nanocomposite modified SPCE was then immersed into different concentrations of bisphenol A for a given time where the tyrosinase reacted with OH group in the bisphenol A to produce the product, 4,4'-isopropylidenebis(1,2-benzoquinone). Cyclic and differential pulse voltammetries at the potential of -0.08 V vs. Ag/AgCl was employed and peak current changes responsible to the reduction of 4,4'-isopropylidenebis(1,2-benzoquinone) were measured which linearly increased with respect to the bisphenol A concentration. In addition, the SPCE based sensor showed excellent selectivity toward an interferent agent, bisphenol S, which has a very similar structure. Finally, the sensor was applied to the analysis of bisphenol A present in an environmental sample solution prepared in our laboratory.