scholarly journals Microfluidic System for Observation of Bacterial Culture and Effects on Biofilm Formation at Microscale

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 606 ◽  
Author(s):  
Xiao-Yan Zhang ◽  
Kai Sun ◽  
Aliya Abulimiti ◽  
Pian-Pian Xu ◽  
Zhe-Yu Li
Keyword(s):  
Membrane Fouling ◽  
Continuous Flow ◽  
Biofilm Formation ◽  
Natural World ◽  
Microfluidic System ◽  
Fluorescence Labeling ◽  
In Situ Observation ◽  
Time Observation ◽  
On Chip ◽  
Bacteria Culture

Biofilms exist in the natural world and applied to many industries. However, due to the variety of characteristics caused by their complex components, biofilms can also lead to membrane fouling and recurrent infections which pose threats to human health. So, to make the best use of their advantages and avoid their disadvantages, knowing the best time and methods for improving or preventing biofilm formation is important. In situ observation without fluorescence labeling in microscale and according to a time scale is useful to research biofilm and confine its formation. In this study, we developed a microfluidic system for real-time observation of bacteria culture and biofilms development at microscale. We cultured E. coli ATCC 25922 on a chip at continuous flow of the velocity, which could promote bacterial formation. Biofilms formation under the condition of adding amoxicillin at different times is also discussed. In addition, the mixed strains from sludge were also cultured on chip, and possible factors in biofilm formation are discussed. Our results show that a microfluidic device could culture microorganisms in continuous flow and accelerate them to adhere to the surface, thereby promoting biofilm formation. Overall, this platform is a useful tool in research on initial biofilm formation, which can contribute to preventing biofouling and infections.

scholarly journals High-Efficiency and High-Throughput On-Chip Exchange of the Continuous Phase in Droplet Microfluidic Systems

2017 ◽  
Vol 22 (5) ◽  
pp. 529-535 ◽  
Author(s):  
Minkyu Kim ◽  
Chia Min Leong ◽  
Ming Pan ◽  
Lucas R. Blauch ◽  
Sindy K. Y. Tang
Keyword(s):  
High Throughput ◽  
Continuous Flow ◽  
High Efficiency ◽  
Scale Up ◽  
Continuous Phase ◽  
Microfluidic System ◽  
Droplet Surface ◽  
Generation Process ◽  
Microfluidic Systems ◽  
On Chip

This article describes an integrated platform for the on-chip exchange of the continuous phase in droplet microfluidic systems. The drops used in this work are stabilized by amphiphilic nanoparticles. For some characterizations and applications of these nanoparticle-stabilized drops, including the measurement of adsorption dynamics of nanoparticles to the droplet surface, it is necessary to change the composition of the continuous phase from that used during the droplet generation process. Thus far, no work has reported the exchange of the continuous phase for a large number (>1 million) of drops in a microfluidic system. This article describes the design and characterization of a high-efficiency and high-throughput on-chip exchanger of the continuous phase in a continuous-flow droplet microfluidic system. The efficiency of exchange was higher than 97%. The throughput was greater than 1 million drops/min, and this can be increased further by increasing the number of parallel exchangers used. Because drops are injected into the exchanger in a continuous-flow manner, the method is directly compatible with automation to further increase its reliability and potential scale-up.

scholarly journals Microfluidics Integration into Low-Noise Multi-Electrode Arrays

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 727
Author(s):  
Mafalda Ribeiro ◽  
Pamela Ali ◽  
Benjamin Metcalfe ◽  
Despina Moschou ◽  
Paulo R. F. Rocha
Keyword(s):  
Continuous Flow ◽  
Electrode Array ◽  
Static Solution ◽  
Microfluidic System ◽  
Low Noise ◽  
Animal Testing ◽  
Electrode Arrays ◽  
Chip Technology ◽  
On Chip

Organ-on-Chip technology is commonly used as a tool to replace animal testing in drug development. Cells or tissues are cultured on a microchip to replicate organ-level functions, where measurements of the electrical activity can be taken to understand how the cell populations react to different drugs. Microfluidic structures are integrated in these devices to replicate more closely an in vivo microenvironment. Research has provided proof of principle that more accurate replications of the microenvironment result in better micro-physiological behaviour, which in turn results in a higher predictive power. This work shows a transition from a no-flow (static) multi-electrode array (MEA) to a continuous-flow (dynamic) MEA, assuring a continuous and homogeneous transfer of an electrolyte solution across the measurement chamber. The process through which the microfluidic system was designed, simulated, and fabricated is described, and electrical characterisation of the whole structure under static solution and a continuous flow rate of 80 µL/min was performed. The latter reveals minimal background disturbance, with a background noise below 30 µVpp for all flow rates and areas. This microfluidic MEA, therefore, opens new avenues for more accurate and long-term recordings in Organ-on-Chip systems.

scholarly journals Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Device for a Biosensor †

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1178 ◽  
Author(s):  
Jorge Prada ◽  
Christina Cordes ◽  
Carsten Harms ◽  
Walter Lang
Keyword(s):  
Microfluidic Device ◽  
Heating Temperature ◽  
Low Cost ◽  
Reaction Chamber ◽  
Microfluidic System ◽  
Heating Process ◽  
Design And Manufacturing ◽  
On Chip ◽  
Working Parameters ◽  
Auto Fluorescence

This contribution outlines the design and manufacturing of a microfluidic device implemented as a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval was carried on after bacteria heat-lysis by an on-chip micro-heater, whose function was characterized at different working parameters. Carbon resistive temperature sensors were tested, characterized and printed on the biochip sealing film to monitor the heating process. Off-chip and on-chip processed RNA were hybridized with capture probes on the reaction chamber surface and identification was achieved by detection of fluorescence tags. The application of the mentioned techniques and materials proved to allow the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the integration potential of fully thermoplastic devices in biosensor systems.

Closed-loop feedback control of microfluidic cell manipulation via deep-learning integrated sensor networks

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Ningquan Wang ◽  
Ruxiu Liu ◽  
Norh Asmare ◽  
Chia-Heng Chu ◽  
Ozgun Civelekoglu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Sensor Networks ◽  
Feedback Control ◽  
Closed Loop ◽  
Microfluidic System ◽  
Cell Manipulation ◽  
Integrated Sensor ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
On Chip

An adaptive microfluidic system changing its operational state in real-time based on cell measurements through an on-chip electrical sensor network.

scholarly journals Silicon-Quartz Microcapillary Opto-Fluidic Platform Obtained by CMOS-Compatible Die to Wafer 200 mm Dual Bonding Process

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1018
Author(s):  
Giuseppe Fiorentino ◽  
Ben Jones ◽  
Sophie Roth ◽  
Edith Grac ◽  
Murali Jayapala ◽  
...  
Keyword(s):  
Adhesive Bonding ◽  
System Analysis ◽  
Quartz Substrate ◽  
Microfluidic System ◽  
Bonding Process ◽  
Microfluidic Channels ◽  
Fully Integrated ◽  
Lab On Chip ◽  
Human Blood Cells ◽  
On Chip

A composite, capillary-driven microfluidic system suitable for transmitted light microscopy of cells (e.g., red and white human blood cells) is fabricated and demonstrated. The microfluidic system consists of a microchannels network fabricated in a photo-patternable adhesive polymer on a quartz substrate, which, by means of adhesive bonding, is then connected to a silicon microfluidic die (for processing of the biological sample) and quartz die (to form the imaging chamber). The entire bonding process makes use of a very low temperature budget (200 °C). In this demonstrator, the silicon die consists of microfluidic channels with transition structures to allow conveyance of fluid utilizing capillary forces from the polymer channels to the silicon channels and back to the polymer channels. Compared to existing devices, this fully integrated platform combines on the same substrate silicon microfluidic capabilities with optical system analysis, representing a portable and versatile lab-on-chip device.

INTEGRATED 3D MULTI-PHYSICAL SIMULATION OF A MICROFLUIDIC SYSTEM USING FINITE ELEMENT ANALYSIS

2015 ◽  
Vol 15 (06) ◽  
pp. 1540043 ◽  
Author(s):  
HAO SUN ◽  
ZHANDONG LI ◽  
JIANGUO TAO
Keyword(s):  
Finite Element ◽  
Physical Simulation ◽  
Microfluidic System ◽  
Von Mises Stress ◽  
Biomedical Science ◽  
Heating Zone ◽  
Element Analysis ◽  
Theoretical Understanding ◽  
Velocity Magnitude ◽  
On Chip

Microfluidics technology has emerged as an attractive approach in physics, chemistry and biomedical science by providing increased analytical accuracy, sensitivity and efficiency in minimized systems. Numerical simulation can improve theoretical understanding, reduce prototyping consumption, and speed up development. In this paper, we setup a 3D model of an integrated microfluidic system and study the multi-physical dynamics of the system via the finite element method (FEM). The fluid–structure interaction (FSI) of fluid and an immobilized single cell within the cell trapping component, and the on-chip thermodynamics have been analyzed. The velocity magnitude and streamline of flow field, the distribution of von Mises stress and Tresca stress on the FSI interface have been studied. In addition, the on-chip heat transfer performance and temperature distribution in the heating zone have been evaluated and analyzed respectively. The presented approach is capable of optimizing microfluidic design, and revealing the complicated mechanism of multi-physical fields. Therefore, it holds the potential for improving microfluidics application in fundamental research and clinical settings.

scholarly journals HrcA and DnaK are important for static and continuous-flow biofilm formation and disinfectant resistance in Listeria monocytogenes

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3782-3790 ◽  
Author(s):  
Stijn van der Veen ◽  
Tjakko Abee
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Peracetic Acid ◽  
Continuous Flow ◽  
Biofilm Formation ◽  
Benzalkonium Chloride ◽  
Wild Type ◽  
Shock Response ◽  
Disinfectant Resistance

The food-borne pathogen Listeria monocytogenes is able to form biofilms in food processing environments. Since biofilms are generally difficult to eradicate during clean-up procedures, they pose a major risk for the food industry. Stress resistance mechanisms involved in L. monocytogenes biofilm formation and disinfectant resistance have, to our knowledge, not been identified thus far. In this study, we investigated the role of hrcA, which encodes the transcriptional regulator of the class I heat-shock response, and dnaK, which encodes a class I heat-shock response chaperone protein, in static and continuous-flow biofilm formation and resistance against benzalkonium chloride and peracetic acid. Induction of both hrcA and dnaK during continuous-flow biofilm formation was observed using quantitative real-time PCR and promoter reporters. Furthermore, in-frame deletion and complementation mutants of hrcA and dnaK revealed that HrcA and DnaK are required to reach wild-type levels of both static and continuous-flow biofilms. Finally, disinfection treatments of planktonic-grown cells and suspended static and continuous-flow biofilm cells of wild-type and mutants showed that HrcA and DnaK are important for resistance against benzalkonium chloride and peracetic acid. In conclusion, our study revealed that HrcA and DnaK are important for L. monocytogenes biofilm formation and disinfectant resistance.

scholarly journals Microfluidic-based imaging of complete C. elegans larval development

2021 ◽  
Author(s):  
Simon Berger ◽  
Silvan Spiri ◽  
Andrew deMello ◽  
Alex Hajnal
Keyword(s):  
Imaging Method ◽  
Cover Glass ◽  
Vulval Development ◽  
C Elegans ◽  
Larval Stages ◽  
Seam Cell ◽  
Time Observation ◽  
On Chip ◽  
First Time

Several microfluidic-based methods for long-term C. elegans imaging have been introduced in recent years, allowing real-time observation of previously inaccessible processes. The ex-isting methods either permit imaging across multiple larval stages without maintaining a stable worm orientation, or allow for very good immobilization but are only suitable for shorter experiments. Here, we present a novel microfluidic imaging method, which allows parallel live-imaging across multiple larval stages, while delivering excellent immobilization and maintaining worm orientation and identity over time. This is achieved by employing an array of microfluidic trap channels carefully tuned to maintain worms in a stable orienta-tion, while allowing growth and molting to occur. Immobilization is supported by an active hydraulic valve, which presses worms onto the cover glass during image acquisition, with the animals remaining free for most of an experiment. Excellent quality images can be ac-quired of multiple worms in parallel, with little impact of the imaging method on worm via-bility or developmental timing. The capabilities of this methodology are demonstrated by observing the hypodermal seam cell divisions and, for the first time, the entire process of vulval development from induction to the end of morphogenesis. Moreover, we demonstrate RNAi on-chip, which allows for perturbation of dynamic developmental processes, such as basement membrane breaching during anchor cell invasion.

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