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Kim DM, Noh HB, Shim YB. Applications of Conductive Polymers to Electrochemical Sensors and Energy Conversion Electrodes. J ELECTROCHEM SCI TE 2013. [DOI: 10.33961/jecst.2013.4.4.125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Kim DM, Noh HB, Shim YB. Applications of Conductive Polymers to Electrochemical Sensors and Energy Conversion Electrodes. J ELECTROCHEM SCI TE 2013. [DOI: 10.5229/jecst.2013.4.4.125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Chandra P, Zaidi SA, Noh HB, Shim YB. Separation and simultaneous detection of anticancer drugs in a microfluidic device with an amperometric biosensor. Biosens Bioelectron 2011; 28:326-32. [PMID: 21820886 DOI: 10.1016/j.bios.2011.07.038] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 07/16/2011] [Accepted: 07/18/2011] [Indexed: 10/18/2022]
Abstract
A simple and highly sensitive method for simultaneous detection of anticancer drugs is developed by integrating the preconcentration and separation steps in a microfluidic device with an amperometric biosensor. An amperometric detection with dsDNA and cardiolipin modified screen printed electrodes are used for the detection of anticancer drugs at the end of separation channel. The preconcentration capacity is enhanced thoroughly using field amplified sample stacking and field amplified sample injection techniques. The experimental parameters affecting the analytical performances, such as pH, temperature, buffer concentration, water plug length, and detection potential are optimized. A reproducible response is observed during multiple injections of samples with a RSD <5%. The calibration plots are linear with the correlation coefficient between 0.9913 and 0.9982 over the range of 2-60 pM. The detection limits of four drugs are determined to be between 1.2 (± 0.05) and 5.5 (± 0.3) fM. The applicability of the device to the direct analysis of anticancer drugs is successfully demonstrated in a real spiked urine sample. Device was also examined for interference effect of common chemicals present in real samples.
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Affiliation(s)
- Pranjal Chandra
- Department of Chemistry and Institute of BioPhysico Sensor Technology, Pusan National University, Busan 609-735, South Korea
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Jiang L, Wang X, Chi L. Nanoscaled surface patterning of conducting polymers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:1309-1321. [PMID: 21506268 DOI: 10.1002/smll.201002356] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Indexed: 05/27/2023]
Abstract
In continuing the steady development of integrated-circuit-related fabrication, the ability to pattern conducting polymers into smaller and smaller sizes in order to realize devices with enhanced performance or even wholly new properties begins to take a more prominent role in their advanced applications. This review summarizes the recent advances in top-down and bottom-up patterning of conducting polymers on surfaces with different approaches including direct writing, in-situ synthesis or assembly, etching, and nanoscratching. All of the latest emerging strategies have the potential to go beyond the current state of the art towards real progress in terms of high-precision positioning, high resolution, high throughout, higher stability, facile processing, and lower-cost production.
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Affiliation(s)
- Lin Jiang
- Physikalisches Institut, Westfaelische Wilhelms-Universitaet Muenster and Center for Nanotechnology (CeNTech), Muenster, Germany
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Noh HB, Lee KS, Lim BS, Kim SJ, Shim YB. Total analysis of endocrine disruptors in a microchip with gold nanoparticles. Electrophoresis 2010; 31:3053-60. [DOI: 10.1002/elps.201000112] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lee KS, Park SH, Won SY, Shim YB. Electrophoretic total analysis of trace tetracycline antibiotics in a microchip with amperometry. Electrophoresis 2009; 30:3219-27. [DOI: 10.1002/elps.200900117] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Shiddiky MJA, Rahman MA, Cheol CS, Shim YB. Fabrication of disposable sensors for biomolecule detection using hydrazine electrocatalyst. Anal Biochem 2008; 379:170-5. [PMID: 18513487 DOI: 10.1016/j.ab.2008.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/03/2008] [Accepted: 05/05/2008] [Indexed: 11/20/2022]
Abstract
We have developed electrochemical DNA and protein sensors on screen-printed electrodes based on the catalytic activity of hydrazine. The sensors use carboxylic acid-functionalized conductive polymer, poly-5,2',5',2''-terthiophene-3'-carboxylic acid (polyTTCA) to make firm immobilization of dendrimer (DEN) through the covalent bond formation between the carboxylic acid groups of polymer and amine groups of dendrimer. The gold nanoparticles (AuNPs) were adsorbed on the remaining amine groups of dendrimer. The thiolated DNA probe or primary antibody was subsequently immobilized on the AuNP-covered dendrimer surfaces. Avidin-labeled hydrazine (Av-Hyd) was then immobilized on the sensor surfaces through the avidin-biotin interaction between the Av-Hyd unit and the biotinylated DNA or secondary antibody. The electrocatalytic reduction current of H(2)O(2) was measured by differential pulse voltammetry. The detection signal was amplified by the polyTTCA/DEN assembly loaded with AuNPs (approximately 3.5 nm) onto which target analyte-linked Av-Hyd was adsorbed. Linear dynamic ranges for the electrocatalytic detection of DNA and human immunoglobulin G (IgG) extending from 50 fM to 7.5 nM and from 40 fg/ml to 2.5 ng/ml, respectively, were observed along with detection limits of approximately 30 fM and 25 fg/ml, respectively. The low detection limit of the disposable sensors offers good promise for practical DNA and protein detection.
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Affiliation(s)
- Muhammad J A Shiddiky
- Department of Chemistry and Center for Innovative BioPhysio Sensor Technology, Pusan National University, Busan 609-735, South Korea.
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Lee KS, Shiddiky MJA, Park SH, Park DS, Shim YB. Electrophoretic analysis of food dyes using a miniaturized microfluidic system. Electrophoresis 2008; 29:1910-7. [DOI: 10.1002/elps.200700556] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rahman MA, Kumar P, Park DS, Shim YB. Electrochemical Sensors Based on Organic Conjugated Polymers. SENSORS (BASEL, SWITZERLAND) 2008; 8:118-141. [PMID: 27879698 PMCID: PMC3681146 DOI: 10.3390/s8010118] [Citation(s) in RCA: 230] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 01/04/2008] [Indexed: 11/20/2022]
Abstract
Organic conjugated polymers (conducting polymers) have emerged as potentialcandidates for electrochemical sensors. Due to their straightforward preparation methods,unique properties, and stability in air, conducting polymers have been applied to energystorage, electrochemical devices, memory devices, chemical sensors, and electrocatalysts.Conducting polymers are also known to be compatible with biological molecules in aneutral aqueous solution. Thus, these are extensively used in the fabrication of accurate,fast, and inexpensive devices, such as biosensors and chemical sensors in the medicaldiagnostic laboratories. Conducting polymer-based electrochemical sensors and biosensorsplay an important role in the improvement of public health and environment because rapiddetection, high sensitivity, small size, and specificity are achievable for environmentalmonitoring and clinical diagnostics. In this review, we summarized the recent advances inconducting polymer-based electrochemical sensors, which covers chemical sensors(potentiometric, voltammetric, amperometric) and biosensors (enzyme based biosensors,immunosensors, DNA sensors).
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Affiliation(s)
- Md Aminur Rahman
- Department of Chemistry and Center for Innovative Bio.Physio Sensor Technology, Pusan National University, Keumjeong-ku, Busan 609-735, South Korea.
| | - Pankaj Kumar
- Department of Chemistry and Center for Innovative Bio.Physio Sensor Technology, Pusan National University, Keumjeong-ku, Busan 609-735, South Korea.
| | - Deog-Su Park
- Department of Chemistry and Center for Innovative Bio.Physio Sensor Technology, Pusan National University, Keumjeong-ku, Busan 609-735, South Korea.
| | - Yoon-Bo Shim
- Department of Chemistry and Center for Innovative Bio.Physio Sensor Technology, Pusan National University, Keumjeong-ku, Busan 609-735, South Korea.
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Polymer microfabrication technologies for microfluidic systems. Anal Bioanal Chem 2007; 390:89-111. [DOI: 10.1007/s00216-007-1692-2] [Citation(s) in RCA: 467] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/05/2007] [Accepted: 10/09/2007] [Indexed: 01/11/2023]
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Roman GT, Kennedy RT. Fully integrated microfluidic separations systems for biochemical analysis. J Chromatogr A 2007; 1168:170-88; discussion 169. [PMID: 17659293 DOI: 10.1016/j.chroma.2007.06.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/05/2007] [Indexed: 10/23/2022]
Abstract
Over the past decade a tremendous amount of research has been performed using microfluidic analytical devices to detect over 200 different chemical species. Most of this work has involved substantial integration of fluid manipulation components such as separation channels, valves, and filters. This level of integration has enabled complex sample processing on miniscule sample volumes. Such devices have also demonstrated high throughput, sensitivity, and separation performance. Although the miniaturization of fluidics has been highly valuable, these devices typically rely on conventional ancillary equipment such as power supplies, detection systems, and pumps for operation. This auxiliary equipment prevents the full realization of a "lab-on-a-chip" device with complete portability, autonomous operation, and low cost. Integration and/or miniaturization of ancillary components would dramatically increase the capability and impact of microfluidic separations systems. This review describes recent efforts to incorporate auxiliary equipment either as miniaturized plug-in modules or directly fabricated into the microfluidic device.
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Affiliation(s)
- Gregory T Roman
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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Abstract
Planar microfluidic devices have emerged as effective tools for the electrophoretic separation of a variety of different DNA inputs. The advancement of this miniaturized platform was inspired initially by demands placed on electrophoretic performance metrics by the human genome project and has provided a viable alternative to slab gel and even capillary formats due to its ability to offer high resolution separations of nucleic acid materials in a fraction of the time associated with its predecessors, consumption of substantially less sample and reagents while maintaining the ability to perform many separations in parallel for realizing ultra-high throughputs. Another compelling advantage of this separation platform is that it offers the potential for integrating front-end sample preprocessing steps onto the separation device eliminating the need for manual sample handling. This review aims to compile a recent survey of various electrophoretic separations using either glass or polymer-based microchips in the areas of genotyping and DNA sequencing as well as those involving the growing field of DNA-based forensics.
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Affiliation(s)
- Rondedrick Sinville
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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Advances in amperometric and conductometric detection in capillary and chip-based electrophoresis. Mikrochim Acta 2007. [DOI: 10.1007/s00604-007-0802-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Du Y, Wang E. Capillary electrophoresis and microchip capillary electrophoresis with electrochemical and electrochemiluminescence detection. J Sep Sci 2007; 30:875-90. [PMID: 17536733 DOI: 10.1002/jssc.200600472] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Recent advances and key strategies in capillary electrophoresis and microchip CE with electrochemical detection (ECD) and electrochemiluminescence (ECL) detection are reviewed. This article consists of four main parts: CE-ECD; microchip CE-ECD; CE-ECL; and microchip CE-ECL. It is expected that ECD and ECL will become powerful tools for CE microchip systems and will lead to the creation of truly disposable devices. The focus is on papers published in the last two years (from 2005 to 2006).
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Affiliation(s)
- Yan Du
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin, PR China
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Shiddiky MJA, Shim YB. Trace Analysis of DNA: Preconcentration, Separation, and Electrochemical Detection in Microchip Electrophoresis Using Au Nanoparticles. Anal Chem 2007; 79:3724-33. [PMID: 17428034 DOI: 10.1021/ac0701177] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have developed a simple and sensitive on-chip preconcentration, separation, and electrochemical detection (ED) method for trace analysis of DNA. The microchip comprised of three parallel channels: the first two are for the field-amplified sample stacking and subsequent field-amplified sampled injection steps, while the third one is for the microchip gel electrophoresis (MGE) with ED (MGE-ED). To improve preconcentration and separation performances of the method, the stacking and separation buffers containing the hydroxypropyl cellulose (HPC) matrix were modified with gold nanoparticles (AuNPs). The formation of AuNPs and HPC/AuNP-modified buffers were characterized by UV-visible spectroscopy and TEM experiments. The conducting polymer-modified electrode was also modified with AuNPs to enhance detection performances of the electrode. The conducting polymer/AuNP layers act as electrocatalysts for the direct detection of DNA based on their oxidation in a solution phase. The total sensitivity was improved by approximately 25 000-fold when compared with a conventional MGE-ED analysis. The calibration plots were linear (r2 = 0.9993) within the range of 0.003-1.0 pg/microL for a 20-bp DNA sample. The sensitivity was 0.20 nA/(fg/microL), with a detection limit of 5.7 amol in a 50-microL sample, based on S/N = 3. The applicability of the method for the analysis of 13 fragments present in a 100-bp DNA ladder was successfully demonstrated.
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Affiliation(s)
- Muhammad J A Shiddiky
- Department of Chemistry, Pusan National University, Keumjeong-ku, Busan 609-735, South Korea
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Liu YS, Walter TM, Chang WJ, Lim KS, Yang L, Lee SW, Aronson A, Bashir R. Electrical detection of germination of viable model Bacillus anthracis spores in microfluidic biochips. LAB ON A CHIP 2007; 7:603-10. [PMID: 17476379 DOI: 10.1039/b702408h] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In this paper, we present a new impedance-based method to detect viable spores by electrically detecting their germination in real time within microfluidic biochips. We used Bacillus anthracis Sterne spores as the model organism. During germination, the spores release polar and ionic chemicals, such as dipicolinic acid (DPA), calcium ions, phosphate ions, and amino acids, which correspondingly increase the electrical conductivity of the medium in which the spores are suspended. We first present macro-scale measurements demonstrating that the germination of spores can be electrically detected at a concentration of 10(9) spores ml(-1) in sample volumes of 5 ml, by monitoring changes in the solution conductivity. Germination was induced by introducing an optimized germinant solution consisting of 10 mM L-alanine and 2 mM inosine. We then translated these results to a micro-fluidic biochip, which was a three-layer device: one layer of polydimethylsiloxane (PDMS) with valves, a second layer of PDMS with micro-fluidic channels and chambers, and the third layer with metal electrodes deposited on a pyrex substrate. Dielectrophoresis (DEP) was used to trap and concentrate the spores at the electrodes with greater than 90% efficiency, at a solution flow rate of 0.2 microl min(-1) with concentration factors between 107-109 spores ml(-1), from sample volumes of 1-5 microl. The spores were captured by DEP in deionized water within 1 min (total volume used ranged from 0.02 microl to 0.2 microl), and then germinant solution was introduced to the flow stream. The detection sensitivity was demonstrated to be as low as about a hundred spores in 0.1 nl, which is equivalent to a macroscale detection limit of approximately 10(9) spores ml(-1). We believe that this is the first demonstration of this application in microfluidic and BioMEMS devices.
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Affiliation(s)
- Yi-Shao Liu
- Birck Nanotechnology Center, Brindley Bioscience Center, School of Electrical and Computer Engineering, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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Hart JP, Crew A, Crouch E, Honeychurch KC, Pemberton RM. Chapter 23 Screen-printed electrochemical (bio)sensors in biomedical, environmental and industrial applications. ELECTROCHEMICAL SENSOR ANALYSIS 2007. [DOI: 10.1016/s0166-526x(06)49023-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Xu X, Li L, Weber SG. Electrochemical and optical detectors for capillary and chip separations. Trends Analyt Chem 2007; 26:68-79. [PMID: 18167508 PMCID: PMC1832263 DOI: 10.1016/j.trac.2006.11.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In separations in capillaries or on chips, the most predominant detectors outside of the field of proteomics are electrochemical (EC) and optical. These detectors operate in the μM to pM range on nL peak volumes with ms time resolution. The driving forces for improvement are different for the two classes of detectors.With EC detectors, there are two limitations that the field is trying to overcome. One is the ever-present surface of the electrode which, while often advantageous for its catalytic or adsorptive properties, is also frequently responsible for changes in sensitivity over time. The other is the decoupling of the electrical systems that operate electrokinetic separations from the system operating the detector.With optical detectors, there are similarly a small number of important limitations. One is the need to bring the portability (size, weight and power requirements) of the detection system into the range of EC detectors. The other is broadening and simplifying the applications of fluorescence detection, as it almost always involves derivatization.Limitations aside, the ability to make detector electrodes and focused laser beams of the order of 1 μm in size, and the rapid time response of both detectors has vaulted capillary and chip separations to the forefront of small sample, fast, low mass-detection limit analysis.
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Affiliation(s)
- Xiaomi Xu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA USA
| | - Ling Li
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA USA
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA USA
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Crevillén AG, Blasco AJ, González MC, Escarpa A. A fast and reliable route integrating calibration and analysis protocols for water-soluble vitamin determination on microchip-electrochemistry platforms. Electrophoresis 2006; 27:5110-8. [PMID: 17161002 DOI: 10.1002/elps.200600213] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel analytical route to determine water-soluble vitamins (B group and C) using single channel microchip-electrochemistry platforms is presented. The electrochemical detection protocol was carefully optimized, and it was shown that it was crucial to use 1 M nitric acid in the detector compartment to detect folic acid. A phosphate buffer (pH 6, 10 mM) and a separation voltage of 2 kV gave the complete separation of vitamins in less than 130 s, with good reproducibility (RSDs less than 10%) and accuracy (error less than 9%). In addition, a methodological innovation integrating calibration and analysis of water-soluble vitamins on the chip is also proposed. The strategy consisted in sequentially using both reservoirs (named calibration and analysis reservoirs) as well as a calibration factor (defined as signal/concentration of analyte). The analytical route required 350 s in the overall protocol (employing 130 s in calibration plus 130 s in analysis), an improvement over the times used in both conventional and microchip protocols.
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Shiddiky MJA, Won MS, Shim YB. Simultaneous analysis of nitrate and nitrite in a microfluidic device with a Cu-complex-modified electrode. Electrophoresis 2006; 27:4545-54. [PMID: 17058308 DOI: 10.1002/elps.200600240] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A CE microsystem coupled with a microchip and a copper-(3-mercaptopropyl) trimethoxysilane (Cu-MPS) complex-modified carbon paste electrode (CPE) was developed for the simultaneous analysis of nitrite and nitrate. The method is based on the electrocatalytic reduction of both analytes with the modified electrode. The Cu-MPS complex was characterized by voltammetric, XPS, and FT-IR analyses. Experimental parameters affecting the sensitivity of the modified electrode were assessed and optimized. The best separation was achieved in a 60 mm separation channel filled with a 20 mM acetate buffer of pH 5.0 containing 3.0 mM CTAB at separation field strength of -250 V/cm within 90 s. The detection potential for the simultaneous analysis of nitrite and nitrate was found to be -225 mV versus Ag/AgCl. A reproducible response (RSD of 3.2% (nitrite) and 2.8% (nitrate), n = 8) for repetitive sample injections reflected the negligible electrode fouling at the modified CPE. The interference effect was examined for other inorganic ions and biological compounds. A wide hydrodynamic range between 0.25 and 120 microM was observed for analyzing nitrite and nitrate with the sensitivities of 0.069 +/- 0.003 and 0.065 +/- 0.002 nA/microM, and the detection limits, based on S/N = 3, were found to be 0.09 +/- 0.007 and 0.08 +/- 0.009 microM, respectively. The applicability of the method to water and urine samples analyses was demonstrated.
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Affiliation(s)
- Muhammad J A Shiddiky
- Department of Chemistry and Center for Innovative BioPhysio Sensor Technology, Pusan National University, Busan, South Korea
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Shiddiky MJA, Rahman MA, Park JS, Shim YB. Analysis of polymerase chain reaction amplifications through phosphate detection using an enzyme–based microbiosensor in a microfluidic device. Electrophoresis 2006; 27:2951-9. [PMID: 16645977 DOI: 10.1002/elps.200500679] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
An electrochemical method was developed for analyzing PCR amplification through the detection of inorganic phosphates (Pi). This method coupled a microchip to a nanoparticle comprising poly-5,2'-5',2''-terthiophene-3'-carboxylic acid (poly-TTCA)/pyruvate oxidase (PyO) modified microbiosensor. It detects Pi produced from the pyrophosphate (PPi), which is released as a byproduct of PCR. After completion of PCR, PPi is hydrolyzed to Pi by inorganic pyrophosphatase. On the microbiosensor surface, pyruvate was converted to H2O2 by PyO in the presence of Pi and oxygen, and subsequently, the anodic current of enzymatically generated H2O2 was detected at +0.5 V versus Ag/AgCl. The CE-EC analysis was completed within 2 min in a coated channel with 75.0 mm separation length at the field strength of -200 V/cm. Excellent operation stability of poly-TTCA/PyO was observed for a long period of analysis. The reproducibility of the analysis yielded an RSD of 3.4% (n = 22) for the peak areas and 1.8% (n = 22) for the migration times. The sensitivity of the analysis was 0.59 +/- 0.01 nA/cycle with a regression coefficient of 0.971.
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Affiliation(s)
- Muhammad J A Shiddiky
- Department of Chemistry and Center for Innovative BioPhysio Sensor Technology, Pusan National University, Keumjeong-ku, Busan, South Korea
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Shiddiky MJA, Park DS, Shim YB. Detection of polymerase chain reaction fragments using a conducting polymer-modified screen-printed electrode in a microfluidic device. Electrophoresis 2006; 26:4656-63. [PMID: 16283692 DOI: 10.1002/elps.200500447] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A simple and fast method for electrochemical detection of amplified fragments by PCR was successfully developed using CE in a microfluidic device with a modified screen-printed carbon electrode (SPCE). The surfaces of the SPCE were modified with poly-5,2'-5',2''-terthiophene-3'-carboxylic acid, which improves the analysis performance by lowering the detection potential, enhancing the S/N characteristics, and avoiding electrode poisoning. DNA fragments amplified by PCR were separated within 210 s in a 75.5 mm-long coated-separation channel at a separation field strength of -200 V/cm. To minimize the sample adsorption into the inner surface of the capillary wall, which disturbs the separation, a dynamically coated capillary with an acrylamide solution was used. Furthermore, the analysis procedure was simplified and rendered reproducible by using 0.50% w/v hydroxyethylcellulose as a separation matrix in a coated channel. The reproducibility of the analysis employing the coated channel yielded RSD of 4.3% for the peak areas and 1.4% for the migration times in eight repetitive measurements at a modified electrode, compared with 21.3 and 9.4% for a bare electrode. The sensitivity of the assay was 18.74 pAs/(pg/microL) with a detection limit of 584.31 +/- 1.3 fg/microL.
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Affiliation(s)
- Muhammad J A Shiddiky
- Department of Chemistry and Center for Innovative BioPhysio Sensor Technology, Pusan National University, Keumjeong-ku, Busan, South Korea
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