Rapid Detection of Viable Microorganisms Based on a  Plate Count Technique Using Arrayed Microelectrodes

Bajwa, Avneet; Tan, Shaoqing Tim; Mehta, Ram Krishna; Bahreyni, Behraad

doi:10.3390/s130708188

Cited by 19 publications

(9 citation statements)

References 23 publications

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“…14 A simpler, intermediate alternative is the detection of secreted molecules produced by bacteria growing on agar plates. 24 This paper proposes a disposable screen-printed electrochemical system embedded within growth agar to continually detect the presence and concentration of PYO. 15 Of these factors, the phenazine molecule pyocyanin (PYO) has great potential to be used as a diagnostic marker, as P. aeruginosa is the only species known to produce this particular molecule.…”

Section: Introductionmentioning

confidence: 99%

Improved monitoring of P. aeruginosa on agar plates

et al. 2015

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Described is the fabrication of a disposable electrochemical assay that is integrated with standard King's A agar culture plates, for the selective and specific detection of Pseudomonas aeruginosa. Agar plates provide several advantages over liquid culture, including protecting the sensor from biofouling and faster identification in small sample volumes. Cultures of P. aeruginosa, starting from initial cell counts of 10 2 to 10 8 cells in 5 microliter volumes, were incubated at 23, 37, and 42 C and monitored both visually and electrochemically. Square wave voltammetry scans confirmed the production of a redox species, pyocyanin, over time that was dependent on the initial load of cells. The pyocyanin easily diffuses through the agar to reach the electrode surface. Using this simple and cheap approach, positive identification of P. aeruginosa was achieved several hours faster via electrochemical detection compared to traditional visual analysis. † Electronic supplementary information (ESI) available: ESI contains a calibration curve for PYO measured in TSB media, solid TSB agar, and solid King's A agar; a plot of the measured maximum current vs. time for the bacterial loads used in Fig. 4; curves from which the maximum PYO production rate in Fig. 2B was calculated; and scanning electron microscopy images of P. aeruginosa grown on King's A agar as well as the surface of the electrodes aer cell growth. See

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Section: Introductionmentioning

confidence: 99%

Improved monitoring of P. aeruginosa on agar plates

et al. 2015

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“…Biosensors offer significant advantages in microbial analysis of water and food samples, as they can include fast or real-time detection, portability, and multi-pathogen detection111718192021. Such systems can potentially be deployed at food processing plants and food safety laboratories to allow for rapid detection of foodborne microorganisms and enhance food safety2223.…”

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confidence: 99%

Porous Silicon-Based Biosensors: Towards Real-Time Optical Detection of Target Bacteria in the Food Industry

Massad-Ivanir

Shtenberg

Raz

et al. 2016

Sci Rep

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Rapid detection of target bacteria is crucial to provide a safe food supply and to prevent foodborne diseases. Herein, we present an optical biosensor for identification and quantification of Escherichia coli (E. coli, used as a model indicator bacteria species) in complex food industry process water. The biosensor is based on a nanostructured, oxidized porous silicon (PSi) thin film which is functionalized with specific antibodies against E. coli. The biosensors were exposed to water samples collected directly from process lines of fresh-cut produce and their reflectivity spectra were collected in real time. Process water were characterized by complex natural micro-flora (microbial load of >107 cell/mL), in addition to soil particles and plant cell debris. We show that process water spiked with culture-grown E. coli, induces robust and predictable changes in the thin-film optical interference spectrum of the biosensor. The latter is ascribed to highly specific capture of the target cells onto the biosensor surface, as confirmed by real-time polymerase chain reaction (PCR). The biosensors were capable of selectively identifying and quantifying the target cells, while the target cell concentration is orders of magnitude lower than that of other bacterial species, without any pre-enrichment or prior processing steps.

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“…Existing microfluidic chip methods for bacteria detection mostly rely on molecular biology methods (Baek et al 2015;Chang et al 2015), light detection Zuo et al 2013), or electrochemical detection . Electrochemical impedance is becoming a potential area for bacteria chip detection (Tomkins et al 2013;Bajwa et al 2013), because it is less time-consuming, non-destructive, and easily integrated with additional components.…”

Section: Introductionmentioning

confidence: 99%

An integrated microsystem with dielectrophoresis enrichment and impedance detection for detection of Escherichia coli

Wang

Liu

et al. 2017

Biomed Microdevices

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An integrated microsystem device with matched interdigitated microelectrode chip was fabricated for enrichment and detection of Escherichia coli O157:H7. The microsystem has integrated with positive dielectrophoresis (pDEP) enrichment and in situ impedance detection, whose total volume is only 3.0 × 10 m, and could provide impedance testing voltages of 0 ~ 10 V, detection frequencies of 1 KHz ~ 1 MHz, DEP excitation signals with amplitude of 0 ~ 10 Vpp and frequencies of 1KHz ~ 1 MHz, which fully meets the demands of pDEP enrichment and impedance detection for bacteria. The microfluidic chip with interdigitated microelectrodes was manufactured by microfabrication methods. The interdigital microelectrode array has sufficient contact area with a bacterial suspension to improve enrichment efficiency and detection sensitivity. Bacteria in the interdigital microelectrode area of the microfluidic chip were firstly captured and enriched by pDEP. Then, in situ impedance detection of the enriched bacteria was realized by switching test conditions. Using the self-assembly microsystem, a novel quantitative detection method was established and demonstrated to detect Escherichia coli O157:H7. Experimental results showed that the detection limits of Escherichia coli O157:H7 was 5 × 10 cfu mL, and testing time was only 6 min under the optimized detection voltage of 100 mV and frequency of 500 KHz. The method was successfully used to detect Escherichia coli O157:H7 in synthetic chicken synthetic samples.

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Rapid Detection of Viable Microorganisms Based on a Plate Count Technique Using Arrayed Microelectrodes

Cited by 19 publications

References 23 publications

Improved monitoring of P. aeruginosa on agar plates

Improved monitoring of P. aeruginosa on agar plates

Porous Silicon-Based Biosensors: Towards Real-Time Optical Detection of Target Bacteria in the Food Industry

An integrated microsystem with dielectrophoresis enrichment and impedance detection for detection of Escherichia coli

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