scholarly journals Development of an Inverted Epifluorescence Microscope for Long-Term Monitoring of Bacteria in Multiplexed Microfluidic Devices

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4140
Author(s):  
Amaro Torres-Simón ◽  
María Henar Marino ◽  
Clara Gómez-Cruz ◽  
Marina Cañadas ◽  
Miguel Marco ◽  
...  
Keyword(s):  
Single Cell ◽  
Bacterial Resistance ◽  
Single Cell Analysis ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Cell Analysis ◽  
Antibiotic Development ◽  
Long Term Monitoring ◽  
Term Monitoring

Developing more efficient methods for antibiotic susceptibility testing is a pressing issue in novel drug development as bacterial resistance to antibiotics becomes increasingly common. Microfluidic devices have been demonstrated to be powerful platforms that allow researchers to perform multiplexed antibiotic testing. However, the level of multiplexing within microdevices is limited, evidencing the need of creating simple, low-cost and high-resolution imaging systems that can be integrated in antibiotic development pipelines. This paper describes the design and development of an epifluorescence inverted microscope that enables long-term monitoring of bacteria inside multiplexed microfluidic devices. The goal of this work is to provide a simple microscope powerful enough to allow single-cell analysis of bacteria at a reduced cost. This facilitates increasing the number of microscopes that are simultaneously used for antibiotic testing. We prove that the designed system is able to accurately detect fluorescent beads of 100 nm, demonstrating comparable features to high-end commercial microscopes and effectively achieving the resolution required for single-cell analysis of bacteria. The proposed microscope could thus increase the efficiency in antibiotic testing while reducing cost, size, weight, and power requirements, contributing to the successful development of new antibiotic drugs.

scholarly journals More than efficacy revealed by single-cell analysis of antiviral therapeutics

2019 ◽  
Author(s):  
Wu Liu ◽  
Mehmet U. Caglar ◽  
Zhangming Mao ◽  
Andrew Woodman ◽  
Jamie J. Arnold ◽  
...  
Keyword(s):  
Single Cell ◽  
Drug Targets ◽  
Single Cell Analysis ◽  
Single Cells ◽  
Principal Component ◽  
Viral Population ◽  
Cell Analysis ◽  
Toxic Dose ◽  
Time Required

SUMMARYDevelopment of antiviral therapeutics emphasizes minimization of the effective dose and maximization of the toxic dose, first in cell culture and later in animal models. Long-term success of an antiviral therapeutic is determined not only by its efficacy but also by the duration of time required for drug-resistance to evolve. We have developed a microfluidic device comprised of ~6000 wells, with each well containing a microstructure to capture single cells. We have used this device to characterize enterovirus inhibitors with distinct mechanisms of action. In contrast to population methods, single-cell analysis reveals that each class of inhibitor interferes with the viral infection cycle in a manner that can be distinguished by principal component analysis. Single-cell analysis of antiviral candidates reveals not only efficacy but also properties of the members of the viral population most sensitive to the drug, the stage of the lifecycle most affected by the drug, and perhaps even if the drug targets an interaction of the virus with its host.

MAGNETOPHORETIC CIRCUIT BIOCOMPATIBILITY

2020 ◽  
Vol 20 (07) ◽  
pp. 2050050
Author(s):  
ROOZBEH ABEDINI-NASSAB
Keyword(s):  
Shear Stress ◽  
Single Cell ◽  
Single Cell Analysis ◽  
Cell Behavior ◽  
Cell Analysis ◽  
Applied Shear Stress ◽  
Cell Handling ◽  
Magnetic Labeling ◽  
Long Term Studies

Recently, we introduced magnetophoretic circuits, composed of overlaid magnetic and metallic layers, as a novel single-cell analysis (SCA) tool. We showed the ability of these circuits in organizing large single-particle and particle-pair arrays. Assembling the cells in microarrays is performed with the ultimate goal of running temporal phenotypic analyses. However, for long-term studies, a suitable microenvironment for the cells to normally grow and differentiate is needed. Towards this goal, in this study, we run required biocompatibility tests, based on which we make the magnetophoretic-based microchip a suitable home for the cells to grow. The results confirm the ability of these chips in cell handling and show no unwanted cell behavior alteration due to the applied shear stress on them, the magnetic labeling, or the microenvironment. After this achievement, this tool would be ready for running important single-cell studies in oncology, virology, and medicine.

scholarly journals Single-cell Analysis with Microfluidic Devices

2019 ◽  
Vol 35 (6) ◽  
pp. 609-618 ◽  
Author(s):  
Xiaowen OU ◽  
Peng CHEN ◽  
Bi-Feng LIU
Keyword(s):  
Single Cell ◽  
Single Cell Analysis ◽  
Microfluidic Devices ◽  
Cell Analysis

scholarly journals Long-Term Monitoring of Atrazine Contamination in Soil by ELISA

2001 ◽  
Vol 84 (1) ◽  
pp. 150-155 ◽  
Author(s):  
Karl Kramer ◽  
Johann Lepschy ◽  
Bertold Hock
Keyword(s):  
Low Cost ◽  
Threshold Value ◽  
Soil Samples ◽  
Sample Throughput ◽  
Atrazine Contamination ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Selection Of ◽  
Hplc Data

Abstract An enzyme-linked immunoassay (ELISA) was used for screening atrazine residues in soil. Samples were annually collected in Southern Germany between 1993 and 1998. An average of 419.5 samples was analyzed per year amounting to 2517 samples. The fraction of positive samples defined by atrazine concentrations >100 μg/kg soil decreased successively from 8% (corresponding to 33 samples) in 1993 to 0.6% (corresponding to 2 samples) in 1998. All positive samples and a selection of negative samples were subsequently validated by HPLC. Comparison of ELISA and HPLC data yielded correlation coefficient values of r= 0.958–0.981 (n= 18–47), except for 1995 when only a correlation of r= 0.864 (n= 18) was obtained. Four samples were overestimated and another 4 were underestimated with respect to the atrazine threshold value of 100 μg/kg soil as revealed by HPLC validation. Thus, 99.68% of 2517 analyzed samples were correctly evaluated. The precision and reproducibility of the ELISA were adequate for a prescreening tool. The low cost per sample and the high sample throughput are not yet achievable by conventional analytical methods. The described combination of ELISA and HPLC has the potential to take advantage of both methods and to restrict determination errors to a minimum.

High-Throughput, Long-Term Imaging of Salmonella Infecting Macrophages in a Micro-Environmental System

2006 ◽  
Author(s):  
Shih-Hui Chao ◽  
Tim J. Strovas ◽  
Ting-She M. Wang ◽  
Kendan A. Jones-Isaac ◽  
Susan L. Fink ◽  
...  
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Laser Scanning ◽  
Single Cell Analysis ◽  
Cell Analysis ◽  
Cellular Functions ◽  
Laser Scanning Confocal Microscope ◽  
History Of ◽  
Multiple Variables

Real-time single cell analysis is necessary to understand dynamic cellular functions in time and space. Such analyses require the simultaneous measurement of multiple variables in real-time, due to heterogeneity in cellular populations. We report the application of using a micro-environmental chamber on an automatic laser scanning confocal microscope to observe murine macrophage cells in incubation conditions for more than 18 hours. The motorized stage of the microscope was programmed to scan through pre-defined monitoring locations to increase the observation throughput. The acquired images were post-processed to extract the information of each cell. In contrast to current single-cell technologies, such as fluorescence-activated cell sorter (FACS) based systems, the reported architecture records the history of the physiological responses of individual cells.

Microscale Oil-Covered Cell Array (MOCCA): A Droplet Array for High-Content Single-Cell Analysis and Imaging

2009 ◽  
Author(s):  
Liang-I Lin ◽  
Shih-Hui Chao ◽  
Deirdre R. Meldrum
Keyword(s):  
Single Cell ◽  
Single Cell Analysis ◽  
Low Cost ◽  
Cell Number ◽  
Cell Analysis ◽  
Cell Array ◽  
Flat Substrate ◽  
Fabrication Procedure ◽  
Droplet Array ◽  
The Cost

A simple, low-cost technique for high throughput single-cell analysis, Microscale Oil-Covered Cell Array (MOCCA), is presented in this paper. Corresponding to recent research on single cell analysis, simple devices for isolated cell chambers are urgently needed and long sought-after. Instead of using microfabricated solid structures to capture cells, MOCCA isolates cells in discrete aqueous droplets that are separated by oil on the patterned hydrophilic areas on a relatively more hydrophobic flat substrate. In our pioneer study, we created an array of 700-picoliter droplets. The randomly seeded E. coli cell number in each discrete droplet approaches single-cell levels. The total time needed for MOCCA fabrication was no more than 10 minutes. Compared to traditional micro-fabrication techniques, MOCCA dramatically lowers the cost and enhances the efficiency for the fabrication procedure, while producing a microscale array as in those made using traditional methods.

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