• The Plant Pathology Journal
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• v.37 no.3
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• pp.291-298
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• 2021

False smut caused by Ustilaginoidea virens is an important rice fungal disease that significantly decreases its production. In the recent past, conventional methods have been developed for its detection that is time-consuming and need high-cost equipments. The research and development in nanotechnology have made it possible to assemble efficient recognition interfaces in biosensors. In this study, we present a simple, sensitive, and selective oxidized graphene-based geno-biosensor for the detection of rice false smut. The biosensor has been developed using a probe DNA as a biological recognition element on paper electrodes, and oxidized graphene to enhance the limit of detection and sensitivity of the sensor. Probe single-stranded DNA (ssDNA) and target ssDNA hybridization on the interface surface has been quantitatively measured with the electrochemical analysis tools namely, cyclic voltammetry, and linear sweep voltammetry. To confirm the selectivity of the device, probe hybridization with non-complementary ssDNA target has been studied. In our study, the developed sensor was able to detect up to 10 fM of target ssDNA. The paper electrodes were employed to produce an effective and cost-effective platform for the immobilization of the DNA and can be extended to design low-cost biosensors for the detection of the other plant pathogens.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1560-1564
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• 2005

The influence of cetyltrimethylammonium bromide (CTAB) on the electrochemical behavior of bisphenol A at the carbon paste electrode (CPE) was investigated. CTAB, with a hydrophobic C-H chain, can adsorb at the CPE surface via hydrophobic interaction and then change the electrode/solution interface, and finally affects the electrochemical response of bisphenol A, confirming from the remarkable oxidation peak current enhancement. The electrode process of bisphenol A was examined, and then all the experimental parameters which affects the electrochemical response of bisphenol A, such as pH value of the supporting electrolyte, accumulation potential and time, potential scan rate and the concentration of CTAB, were examined. Finally, a sensitive and simple voltammetric method was developed for the determination of bisphenol A. Under the optimum conditions, the oxidation peak current of bisphenol A varied linearly with its concentration over the range from $2.5\;{\times}\;10^{-8}\;to\;1\;{\times}\;10^{-6}$ mol/L, and the detection limit was found to be $7.5\;{\times}\;10^{-9}$ mol/L. This method was successfully employed to determine bisphenol A in some waste plastic samples.

• Journal of the Korean Electrochemical Society
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• v.19 no.4
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• pp.134-140
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• 2016

An aptamer-based biosensor using a new redox indicator has been examined for the electrochemical detection of thrombin. The aptamer modified primary aliphatic amine was covalently immobilized onto poly-(5,2':5',2"-terthiophene-3'-carboxylic acid) (polyTTCA) layer. Tetrabromophenolphthalein ethyl ester (KTBPE) was interacted to aptamer and used as an electrochemical indicator. Prior to the detection, the oxidation reaction of KTBPE onto aptamer modified layer was also investigated using differential pulse voltammetry. The characterization of the final sensor (KTBPE/aptamer -polyTTCA) was performed by voltammetry, QCM, and ESCA. After binding of thrombin onto KTBPE/aptamer based sensor, the peak signal of KTBPE was gradually decreased. The sensor exhibited a dynamic range between 10.0 and 100.0 nM with the detection limit of $1.0{\pm}0.2nM$.

• Analytical Science and Technology
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• v.8 no.4
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• pp.887-894
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• 1995

Toward the development of universal, sensitive, and convenient method of DNA (or RNA) detection, two kinds of electrochemically active DNA ligands. acridine - viologen and oligonucleotide - ferrocene conjugate, were prepared. Thermodynamic and electrochemical study revealed that these probes bound strongly to DNA, and showed a typical cyclic voltammograms, indicating a potential for use as a reversible electrochemical labelling agent for DNA. Especially, using the electrochemically active oligonucleotide, we have been able to demonstrate the detection of DNA at femtomole levels by HPLC equipped with ordinary electrochemical detector (ECD). These results lead to the conclusion that the redox-active probes are very useful for the microanalysis of nucleic acid due to the stabilily of the complexes, high detection sensitivity, and wide applicability to the target structures (single- and double strands) and sequences.

• Archives of Pharmacal Research
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• v.24 no.4
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• pp.355-359
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• 2001

A novel HPLC method with electrochemical detection has been developed for the determination of recombinant human epidermal growth factor (rhEGF) in pharmaceutical products. rhEGF was separated from other components in formulation on a reversed-phase C18 column with 24% acetonitrile in 0.1 M phosphate buffer (pH 4.75). The optimum electrochemical oxidation of EGF was obtained at 0.85 V vs. Ag/AgCl in a glassy carbon working electrode due to electroactive tyrosine, tryptophan, methionine, and arginine residues. The quantitation range was from 1.0 to 200 ng of rhEGF with the linear correlation coefficient greater than 0.999. The method was successfully applied for the quantitation of rhEGF in a pharmaceutical preparation.

• 한국전기화학회:학술대회논문집
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• 2004.04a
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• pp.27-27
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• 2004

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.52-57
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• 2023

This study is a basic research for the development of high performance flexible electrode material. To enhance its electrochemical property, CuO nanoparticles (CuO NPs) were introduced and dispersed on surface of CNT fiber through electrochemical deposition method. The CNT fiber/CuO NPs electrode was fabricated and applied to electrochemical non-enzymatic glucose sensor. Surface morphology and elemental composition of the CNT fiber/CuO NPs electrode was characterized by scanning electron microscope (SEM) with energy dispersive X-ray spectrometry (EDS). And its electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The CNT fiber/CuO NPs electrode exhibited the good sensing performance for glucose detection such as high sensitivity, wide linear range, low detection limit and good selectivity due to synergetic effect of CNT fiber and CuO NPs. Based on the unique property of CNT fiber, CuO NPs were provide large surface area, enhanced electrocatalytic activity, efficient electron transport property. Therefore, it is expected to develop high performance flexible electrode materials using various nanomaterials.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.1-14
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• 2023

The overuse of pesticides in agricultural sectors exposes people to food contamination. Pesticides are toxic to humans and can have both acute and chronic health effects. To protect food consumers from the adverse effects of pesticides, a rapid monitoring system of the residues is in dire need. Molecularly imprinted polymer (MIP) on a screen-printed electrode (SPE) is a leading and promising electrochemical sensing approach for the detection of several residues including pesticides. Despite the huge development in analytical instrumentation developed for contaminant detection in recent years such as HPLC and GC/MS, these conventional techniques are time-consuming and labor-intensive. Additionally, the imprinted SPE detection system offers a simple portable setup where all electrodes are integrated into a single strip, and a more affordable approach compared to MIP attached to traditional rod electrodes. Recently, numerous reviews have been published on the production and sensing applications of MIPs however, the research field lacks reviews on the use of MIPs on electrochemical sensors utilizing the SPE technology. This paper presents a distinguished overview of the MIP technique used on bare and modified SPEs for the detection of pesticides from four recent publications which are malathion, chlorpyrifos, paraoxon and cyhexatin. Different molecular imprint routes were used to prepare these biomimetic sensors including solution polymerization, thermal polymerization, and electropolymerization. The unique characteristics of each MIP-modified SPE are discussed and the comparison among the findings of the papers is critically reviewed.

• Journal of Electrochemical Science and Technology
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• v.3 no.2
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• pp.90-94
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• 2012

A simple and sensitive electrochemical sensor for simultaneous and quantitative detection of ranitidine (RT) and metronidazole (MT) was developed, based on a poly(thionine)-modified anodized glassy carbon electrode (PTH/GCE). The modified electrode showed the excellent electrocatalytic activity towards the reduction of both RT and MT in 0.1M phosphate buffer solution (PBS, pH 7.0). The peak-to-peak separations (${\Delta}E_p$) for the simultaneous detection of RT and MT between the two reduction waves in CV and DPV were increased significantly from ca. 100 mV at anodized GCE, to ca. 550 mV at the PTH/GCE. The reduction peak currents of RT and MT were linear over the range from 35 to $500{\mu}M$ in the presence of 200 and $150{\mu}M$ of RT and MT, respectively. The sensor showed the sensitivity of 0.58 and $0.78{\mu}A/cm^2/{\mu}M$ with the detection limits (S/N = 3) of 1.5 and $0.96{\mu}M$, respectively for RT and MT.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1569-1571
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• 2002

The determination of DNA hybridization can apply the molecular biology research, clinic diagnostics, bioengineering, environment monitoring, food science and other application area. So, The determination of hybridization is very important for the improvement of DNA detection system. In this study, we report the characterization of the DNA hybridization by the electricalchemical methods. A new electrochemical biosensor is described for voltammetric detection of gene sequence related to probe oligonucleotide of bacterium Escherichia coli O157:H7. The biosensor involves the immobilization of a 18-mer probe oligonucleotide, which is complemetary to a specific gene sequence related to Escherichia coli O157:H7 on a gold electrode through specific adsorption. The probe oligonucleotide was used to determine the amount of target oligonucleotide in solution using mitoxantrone(MTX) as the electrochemical indicators. The cathodic peak currents $(I_{peak})$ of MTX were linearly related to the concentration of the target oligonucleotide sequence in the range $1[{\mu}M]{\sim}0.1[nM]$. The detection limit of this approach was 0.01[nM]. In addition, these indicators were capable of selectivity discriminating against various mismatching condition.