Demonstration of labeless detection of food pathogens using electrochemical redox probe and screen printed gold electrodes

Susmel, Sabina; Guilbault, George G.; O’Sullivan, Ciara K.

doi:10.1016/s0956-5663(02)00214-2

Cited by 82 publications

(39 citation statements)

References 20 publications

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“…Amperometric biosensors for detection of in vitro cultivated bacteria using antibody capture or nucleic acid hybridization approaches have been described, but not for detection of bacteria in clinical specimens (1,4,9,10,15,21,26,30,35,40,43). A convergence of technological innovations from several disciplines, including microfabrication, materials science, electrochemistry, and molecular microbiology, contributed to the design of the electrochemical sensor array and the detection strategy utilized in the current study (16,17,42).…”

Section: Discussionmentioning

confidence: 99%

Use of Electrochemical DNA Biosensors for Rapid Molecular Identification of Uropathogens in Clinical Urine Specimens

Liao¹,

Mastali²,

et al. 2006

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We describe the first species-specific detection of bacterial pathogens in human clinical fluid samples using a microfabricated electrochemical sensor array. Each of the 16 sensors in the array consisted of three single-layer gold electrodes-working, reference, and auxiliary. Each of the working electrodes contained one representative from a library of capture probes, each specific for a clinically relevant bacterial urinary pathogen. The library included probes for Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterocococcus spp., and the Klebsiella-Enterobacter group. A bacterial 16S rRNA target derived from single-step bacterial lysis was hybridized both to the biotin-modified capture probe on the sensor surface and to a second, fluorescein-modified detector probe. Detection of the target-probe hybrids was achieved through binding of a horseradish peroxidase (HRP)-conjugated anti-fluorescein antibody to the detector probe. Amperometric measurement of the catalyzed HRP reaction was obtained at a fixed potential of ؊200 mV between the working and reference electrodes. Species-specific detection of as few as 2,600 uropathogenic bacteria in culture, inoculated urine, and clinical urine samples was achieved within 45 min from the beginning of sample processing. In a feasibility study of this amperometric detection system using blinded clinical urine specimens, the sensor array had 100% sensitivity for direct detection of gram-negative bacteria without nucleic acid purification or amplification. Identification was demonstrated for 98% of gram-negative bacteria for which species-specific probes were available. When combined with a microfluidics-based sample preparation module, the integrated system could serve as a point-of-care device for rapid diagnosis of urinary tract infections.Urinary tract infection (UTI) is the most common urological disease in the United States and the second most common bacterial infection of any organ system (12, 32). UTI is a major cause of patient morbidity and health care expenditure for all age groups, accounting for over 7 million office visits and more than 1 million hospital admissions per year (39). Catheterassociated UTI accounts for 40% of all nosocomial infections and more than 1 million cases per year (22,41,49). The total cost of UTI to the United States health care system in the year 2000 was approximately $3.5 billion (13,19,20). An important component of these health care costs involves the processing of urine specimens by clinical microbiology laboratories. Urine is the type of body fluid most frequently submitted to clinical microbiology laboratories for culture. A major drawback of microbiological culture systems is the time lag of approximately 2 days between specimen collection and pathogen identification. The primary cause of the delay between specimen collection and pathogen identification is the time to colony formation after the specimen is plated on solid culture media.

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Section: Discussionmentioning

confidence: 99%

Use of Electrochemical DNA Biosensors for Rapid Molecular Identification of Uropathogens in Clinical Urine Specimens

Liao¹,

Mastali²,

et al. 2006

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“…The exploitation of thiol based SAMs for immobilization of antibodies in immunosensing has also been previously reported [16]. However, immobilization of biocomponents can reduce their activity and several strategies should be tested to obtain optimum coupling of the biocomponent of the particular system under investigation.…”

Section: Introductionmentioning

confidence: 96%

Development of an Amperometric Immunosensor for the Quantification of Staphylococcus aureus Using Self‐Assembled Monolayer‐Modified Electrodes as Immobilization Platforms

et al. 2007

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Amperometric immunosensors for the detection and quantification of S. aureus using MPA self-assembled monolayer modified electrodes for the immobilization of the immunoreagents are reported. Two different immunosensor configurations were compared. A competitive mode, in which protein A-bearing S. aureus cells and antiRbIgG labeled with horseradish peroxidase (HRP) compete for the binding sites of RbIgG immobilized onto the 3-mercaptopropionic acid (MPA) modified electrode, was evaluated. Moreover, a sandwich configuration in which S. aureus cells were immobilized onto the MPA SAM, and RbIgG and antiRbIgG labeled with HRP were further linked to the electrode surface, was also tested. In both cases, TTF was used as the redox mediator of the HRP reaction with H 2 O 2 , and it was co-immobilized onto the MPA-modified gold electrode. After optimization of the working variables for both configurations, the analytical performance of the amperometric measurements carried out at 0.00 V (vs. Ag/ AgCl) showed that the competitive immunosensor exhibited a lower limit of detection (1.6 Â 10 5 S. aureus cells mL À1 ), as well as a better repeatability and reproducibility of the measurements.

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“…In the recent years, microfluidics has generated great excitement due to its potential of providing rapid analyses with high resolutions and low costs for a wide range of biological and chemical applications [25][26][27][28][29][30][31][32]. The integrated microfluidic system will play a key role in biochemistry, molecular biology and synthesis protocols [33], and is expected to have major impacts on biomedical research, clinical diagnosis [29], point of care, food pathogen screening [34] and environmental monitoring by providing automated and portable solutions to a wide range of fluid based problems [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Cascade and staggered dielectrophoretic cell sorters

Yang

Hong

et al. 2011

Electrophoresis

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We have developed two new microfluidic cell sorters based on conventional negative dielectrophoresis (DEP) for continuous flow operations. The first is a cascade configuration sorter designed to increase purity of isolated target cell. The second has two staggered side channels in opposite side walls to increase sample throughput without compromising enrichment factor. Particles (carboxylate microspheres) of different sizes were first used to demonstrate the feasibility of the present DEP sorters for cell isolation. Then biological cells, i.e. human prostate cancer cell line LNCaP and human colorectal cancer cell line HCT116 were used to test the performance of the DEP sorters. In the present work, applied voltage was in the range of 0-20 V(p-p) , and frequency was from 0 to 10 MHz. Comparing to a single side channel DEP cell sorter, the isolation purity was improved from 80 to 96% by a single cascade sorter and the sample throughput was increased from 0.2 to 0.65 μL/min by a single staggered side channel sorter. In this article, we report the cell sorter designs, cell separation and enrichment factors.

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Demonstration of labeless detection of food pathogens using electrochemical redox probe and screen printed gold electrodes

Cited by 82 publications

References 20 publications

Use of Electrochemical DNA Biosensors for Rapid Molecular Identification of Uropathogens in Clinical Urine Specimens

Use of Electrochemical DNA Biosensors for Rapid Molecular Identification of Uropathogens in Clinical Urine Specimens

Development of an Amperometric Immunosensor for the Quantification of Staphylococcus aureus Using Self‐Assembled Monolayer‐Modified Electrodes as Immobilization Platforms

Cascade and staggered dielectrophoretic cell sorters

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