Fast fluorometric enumeration of E. coli using passive chip

Kasap, E.; Dogan, Üzeyir; Çoğun, Ferah; Yıldırım, Ender; Boyaci, İsmail Hakkı; Çetin, Demet; Suludere, Zekiye; Tamer, Uğur; Ertaş, Nusret

doi:10.1016/j.mimet.2019.105680

Cited by 13 publications

(4 citation statements)

References 47 publications

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“…The maximum actual capture rate was 87.27%, and the best capture time was 10 min while the traditional cultivation detection time is 18 to 24 h. There was a good linear relationship (R 2 = 0.9926 > 0.90) between the average fluorescence optical density of the chip and the concentration from 4.91 × 10 to 4.91 × 10 7 cfu/μL. Therefore, the minimum detection limit is 4.91 × 10 cfu/μL, and the maximum is 4.91 × 10 7 cfu/μL, which is in accordance with the passive microfluidic chip trend as well [34]. The cost of the microfluidic chip designed in this experiment is approximately RMB 10, less than one tenth of the current market price.…”

Section: Discussionsupporting

confidence: 78%

Microfluidics for the rapid detection of Escherichia coli O157:H7 using antibody-coated microspheres

Shopsin

Sun

et al. 2021

Bioengineered

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This study developed a novel method for the rapid detection of Escherichia coli (E. coli) O157:H7 on a microfluidic platform. First, the concentration of bacteria in a sample was determined with the adenosine triphosphate (ATP) method. Then, the specific detection of E. coli was achieved in a microfluidic chip by the immune-microsphere technique. The influences of the culture time, flow rate and capture time on the detection of the target bacteria were investigated systematically. Generally, with increasing capture time, more bacteria could be captured by the microspheres, which had a positive effect on bacterial detection. Furthermore, the sensitivity and specificity of the method were also tested. The results showed that this method could specifically detect E. coli with a sensitivity as high as 49.1 cfu/μL; the consumption of bacteria was 1 μL, and the reagent was at the microliter level. The testing time can be controlled within one and a half hours, and the cost of testing was approximately RMB 10. The method described in this article is simple and accurate and has great application value in bacterial detection for medical diagnostics.

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Section: Discussionsupporting

confidence: 78%

Microfluidics for the rapid detection of Escherichia coli O157:H7 using antibody-coated microspheres

Shopsin

Sun

et al. 2021

Bioengineered

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“…In our previous studies, we generated quantum dot nanoparticles (QDs) as labels and fluorescence measurements were described in order to evaluate the applicability of the method using tap water and lake water samples [ 17 , 19 ]. The main limitation in the fluorescence-based immunoassay is the time-consuming modification steps of QDs.…”

Section: Resultsmentioning

confidence: 99%

“…Plate counting (24–48 h) methods should be replaced by novel biosensor systems as an alternative reliable pathogen detection technique, demonstrated by the use of nanoparticles in last few years [ 5 , 6 , 7 ]. In these developed biosensor systems, different analytical techniques are used, such as surface enhanced Raman scattering (SERS) [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], fluorescence [ 16 , 17 , 18 , 19 ], enzyme-linked immunosorbent assay (ELISA) [ 20 , 21 , 22 ], surface plasmon resonance (SPR) [ 23 , 24 ], electrochemical methods [ 25 , 26 , 27 ] and colorimetric methods [ 28 , 29 ]. SERS is a very good alternative analytical technique due to its high sensitivity, which can even detect a single bacterium.…”

Section: Introductionmentioning

confidence: 99%

Escherichia coli Enumeration in a Capillary-Driven Microfluidic Chip with SERS

et al. 2022

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Pathogen detection is still a challenging issue for public health, especially in food products. A selective preconcentration step is also necessary if the target pathogen concentration is very low or if the sample volume is limited in the analysis. Plate counting (24–48 h) methods should be replaced by novel biosensor systems as an alternative reliable pathogen detection technique. The usage of a capillary-driven microfluidic chip is an alternative method for pathogen detection, with the combination of surface-enhanced Raman scattering (SERS) measurements. Here, we constructed microchambers with capillary microchannels to provide nanoparticle–pathogen transportation from one chamber to the other. Escherichia coli (E. coli) was selected as a model pathogen and specific antibody-modified magnetic nanoparticles (MNPs) as a capture probe in a complex milk matrix. MNPs that captured E. coli were transferred in a capillary-driven microfluidic chip consisting of four chambers, and 4-aminothiophenol (4-ATP)-labelled gold nanorods (Au NRs) were used as the Raman probe in the capillary-driven microfluidic chip. The MNPs provided immunomagnetic (IMS) separation and preconcentration of analytes from the sample matrix and then, 4-ATP-labelled Au NRs provided an SERS response by forming sandwich immunoassay structures in the last chamber of the capillary-driven microfluidic chip. The developed SERS-based method could detect 101–107 cfu/mL of E. coli with the total analysis time of less than 60 min. Selectivity of the developed method was also tested by using Salmonella Enteritidis (S. Enteritidis) and Staphylococcus aureus (S. aureus) as analytes, and very weak signals were observed.

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“…In passive microfluidics, the progress of the fluids in the channels is obtained through the internal dynamics of the system, i.e., the system is kept at a certain slope or under pressure [ 21 , 22 ]. In some passive chips, liquids are transferred to the system through access holes by pipetting, and the liquids remain constant in the system while target cells loaded with magnetic particles are moved using an external magnetic field [ 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Simple Staining of Cells on a Chip

2022

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Simple staining of cells is a widely used method in basic medical diagnostics, education, and research laboratories. The stains are low-cost, but the extensive consumption results in excessive toxic waste generation. Thus, to decrease the amount of toxic waste resulting from the cell staining procedure is a need. In this study, we developed a magnetically driven and compartmentalized passive microfluidic chip to perform simple staining of human eukaryotic cells, K562 cells, and lymphocyte cells derived from patients. We demonstrated simple staining on cells with trypan blue, methylene blue, crystal violet, and safranin for high, medium, and low cell densities. The stained cells were imaged using a bright field optical microscope and a cell phone to count cells on the focal plane. The staining improved the color signal of the cell by 25-135-pixel intensity changes for the microscopic images. The validity of the protocol was determined using Jurkat and MDA-MB-231 cell lines as negative controls. In order to demonstrate the practicality of the system, lymphocyte cells derived from human blood samples were stained with trypan blue. The color intensity changes in the first and last compartments were analyzed to evaluate the performance of the chip. The developed method is ultra-low cost, significantly reduces the waste generated, and can be integrated with mobile imaging devices in terms of portability. By combining microfabrication technology with cell staining, this study reported a novel contribution to the field of microfluidic biosensors. In the future, we expect to demonstrate the detection of pathogens using this method.

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Fast fluorometric enumeration of E. coli using passive chip

Cited by 13 publications

References 47 publications

Microfluidics for the rapid detection of Escherichia coli O157:H7 using antibody-coated microspheres

Microfluidics for the rapid detection of Escherichia coli O157:H7 using antibody-coated microspheres

Escherichia coli Enumeration in a Capillary-Driven Microfluidic Chip with SERS

Simple Staining of Cells on a Chip

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