scholarly journals Detection of Cellular Parameters Using a Microfluidic Chip-Based System

2002 ◽  
Vol 7 (4) ◽  
pp. 85-89 ◽  
Author(s):  
Tobias Preckel ◽  
Gerd Luedke ◽  
Samuel D. H. Chan ◽  
Benjamin N. Wang ◽  
Robert Dubrow ◽  
...  
Keyword(s):  
Lab On A Chip ◽  
Microfluidic System ◽  
Microfluidic Channels ◽  
Microfluidic Chips ◽  
Fluorescence Detector ◽  
Single File ◽  
Chip Technology ◽  
Cell Assays ◽  
Pressure Driven Flow

Lab-on-a-chip technology achieves a reduction of sample and reagent volume and automates complex laboratory processes. Here, we present the implementation of cell assays on a microfluidic platform using disposable microfluidic chips. The applications are based on the controlled movement of cells by pressure-driven flow inside networks of microfluidic channels. Cells are hydrodynamically focused and pass the fluorescence detector in single file. Initial applications are the determination of protein expression and apoptosis parameters. The microfluidic system allows unattended measurement of six samples per chip. Results obtained with the microfluidic chips showed good correlation with data obtained using a standard flow cytometer.

Determination of pore-scale hydrate phase equilibria in sediments using lab-on-a-chip technology

Lab on a Chip ◽  
2017 ◽  
Vol 17 (23) ◽  
pp. 4070-4076 ◽  
Author(s):  
Stian Almenningen ◽  
Josef Flatlandsmo ◽  
Anthony R. Kovscek ◽  
Geir Ersland ◽  
Martin A. Fernø
Keyword(s):  
Porous Media ◽  
Phase Equilibria ◽  
Lab On A Chip ◽  
Pore Scale ◽  
Experimental Protocol ◽  
Fast Determination ◽  
Chip Technology ◽  
Hydrate Phase ◽  
Hydrate Stability

We present an experimental protocol for fast determination of hydrate stability in porous media for a range of pressure and temperature conditions.

Lab-on-a-chip technology for determination of protein isoform profiles

2006 ◽  
Vol 1127 (1-2) ◽  
pp. 175-182 ◽  
Author(s):  
Maria Lönnberg ◽  
Jan Carlsson
Keyword(s):  
Lab On A Chip ◽  
Chip Technology ◽  
Protein Isoform

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

scholarly journals Microfluidic Network Simulations Enable On-Demand Prediction of Control Parameters for Operating Lab-On-A-Chip-Devices

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1320
Author(s):  
Julia Sophie Böke ◽  
Daniel Kraus ◽  
Thomas Henkel
Keyword(s):  
Fluid Management ◽  
Lab On A Chip ◽  
Microfluidic System ◽  
Flow Rates ◽  
Demand Prediction ◽  
Fast Running ◽  
Microfluidic Network ◽  
Fluid Properties ◽  
Network Simulations ◽  
User Friendly

Reliable operation of lab-on-a-chip systems depends on user-friendly, precise, and predictable fluid management tailored to particular sub-tasks of the microfluidic process protocol and their required sample fluids. Pressure-driven flow control, where the sample fluids are delivered to the chip from pressurized feed vessels, simplifies the fluid management even for multiple fluids. The achieved flow rates depend on the pressure settings, fluid properties, and pressure-throughput characteristics of the complete microfluidic system composed of the chip and the interconnecting tubing. The prediction of the required pressure settings for achieving given flow rates simplifies the control tasks and enables opportunities for automation. In our work, we utilize a fast-running, Kirchhoff-based microfluidic network simulation that solves the complete microfluidic system for in-line prediction of the required pressure settings within less than 200 ms. The appropriateness of and benefits from this approach are demonstrated as exemplary for creating multi-component laminar co-flow and the creation of droplets with variable composition. Image-based methods were combined with chemometric approaches for the readout and correlation of the created multi-component flow patterns with the predictions obtained from the solver.

scholarly journals Microscopic Analysis of Bacterial Inoculum Effect Using Micropatterned Biochip

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 300
Author(s):  
Jung Ho Hwang ◽  
Sang Young Lee ◽  
Jungil Choi
Keyword(s):  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Microscopic Analysis ◽  
Microfluidic System ◽  
Timely Manner ◽  
Testing Conditions ◽  
Bacterial Inoculum ◽  
Clinical Environments ◽  
Inoculum Effect

Antimicrobial resistance has become a major problem in public health and clinical environments. Against this background, antibiotic susceptibility testing (AST) has become necessary to cure diseases in an appropriate and timely manner as it indicates the necessary concentration of antibiotics. Recently, microfluidic based rapid AST methods using microscopic analysis have been shown to reduce the time needed for the determination of the proper antibiotics. However, owing to the inoculum effect, the accurate measurement of the minimal inhibitory concentration (MIC) is difficult. We tested four standard bacteria: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis, against five different antibiotics: piperacillin, cefotaxime, amikacin, levofloxacin, and ampicillin. The results showed that overall, the microfluidic system has a similar inoculum effect compared to the conventional AST method. However, due to the different testing conditions and determination protocols of the growth of the microfluidic based rapid AST, a few results are not identical to the conventional methods using optical density. This result suggests that microfluidic based rapid AST methods require further research on the inoculum effect for practical use in hospitals and can then be used for effective antibiotic prescriptions.

scholarly journals Design and experimental investigation of a novel spiral microfluidic chip to separate wide size range of micro-particles aimed at cell separation

2021 ◽  
pp. 095441192110297
Author(s):  
Seyed Ali Tabatabaei ◽  
Mohammad Zabetian Targhi
Keyword(s):  
Point Of Care ◽  
Diagnostic System ◽  
Average Diameter ◽  
Microfluidic System ◽  
Microfluidic Chips ◽  
Medical Sciences ◽  
Blood Samples ◽  
Micro Particles ◽  
Monodisperse Polystyrene ◽  
Device Size

Isolation of microparticles and biological cells on microfluidic chips has received considerable attention due to their applications in numerous areas such as medical and engineering fields. Microparticles separation is of great importance in bioassays due to the need for smaller sample and device size and lower manufacturing costs. In this study, we first explain the concepts of separation and microfluidic science along with their applications in the medical sciences, and then, a conceptual design of a novel inertial microfluidic system is proposed and analyzed. The PDMS spiral microfluidic device was fabricated, and its effects on the separation of particles with sizes similar to biological particles were experimentally analyzed. This separation technique can be used to separate cancer cells from the normal ones in the blood samples. These components required for testing were selected, assembled, and finally, a very affordable microfluidic kit was provided. Different experiments were designed, and the results were analyzed using appropriate software and methods. Separator system tests with polydisperse hollow glass particles (diameter 2–20 µm), and monodisperse Polystyrene particles (diameter 5 & 15 µm), and the results exhibit an acceptable chip performance with 86% of efficiency for both monodisperse particles and polydisperse particles. The microchannel collects particles with an average diameter of 15.8, 9.4, and 5.9 μm at the proposed reservoirs. This chip can be integrated into a more extensive point-of-care diagnostic system to test blood samples.

scholarly journals Testing Lab-on-a-Chip Technology for Culturing Human Melanoma Cells under Simulated Microgravity

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 402
Author(s):  
Dawid Przystupski ◽  
Agata Górska ◽  
Olga Michel ◽  
Agnieszka Podwin ◽  
Patrycja Śniadek ◽  
...  
Keyword(s):  
Simulated Microgravity ◽  
Lab On A Chip ◽  
Human Keratinocytes ◽  
Melanoma Cells ◽  
Short Exposure ◽  
Biological Research ◽  
Cell Physiology ◽  
Caspase Activity ◽  
Chip Technology ◽  
Cells Cultured

The dynamic development of the space industry makes space flights more accessible and opens up new opportunities for biological research to better understand cell physiology under real microgravity. Whereas specialized studies in space remain out of our reach, preliminary experiments can be performed on Earth under simulated microgravity (sµg). Based on this concept, we used a 3D-clinostat (3D-C) to analyze the effect of short exposure to sµg on human keratinocytes HaCaT and melanoma cells A375 cultured on all-glass Lab-on-a-Chip (LOC). Our preliminary studies included viability evaluation, mitochondrial and caspase activity, and proliferation assay, enabling us to determine the effect of sµg on human cells. By comparing the results concerning cells cultured on LOCs and standard culture dishes, we were able to confirm the biocompatibility of all-glass LOCs and their potential application in microgravity research on selected human cell lines. Our studies revealed that HaCaT and A375 cells are susceptible to simulated microgravity; however, we observed an increased caspase activity and a decrease of proliferation in cancer cells cultured on LOCs in comparison to standard cell cultures. These results are an excellent basis to conduct further research on the possible application of LOCs systems in cancer research in space.

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