In Situ Single-Cell Stimulation and Real-Time Electrochemical Detection of Lactate Response Using a Microfluidic Probe

2021 ◽  
Author(s):  
Lin Zhou ◽  
Nahoko Kasai ◽  
Hizuru Nakajima ◽  
Shungo Kato ◽  
Sifeng Mao ◽  
...  
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Electrochemical Detection ◽  
Cell Stimulation

scholarly journals A microfluidic platform for in situ investigation of biofilm formation and its treatment under controlled conditions

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Hervé Straub ◽  
Leo Eberl ◽  
Manfred Zinn ◽  
René M. Rossi ◽  
Katharina Maniura-Weber ◽  
...  
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Rich Medium ◽  
Flow Conditions ◽  
Microfluidic Platform ◽  
Adhesion Rate

Abstract Background Studying bacterial adhesion and early biofilm development is crucial for understanding the physiology of sessile bacteria and forms the basis for the development of novel antimicrobial biomaterials. Microfluidics technologies can be applied in such studies since they permit dynamic real-time analysis and a more precise control of relevant parameters compared to traditional static and flow chamber assays. In this work, we aimed to establish a microfluidic platform that permits real-time observation of bacterial adhesion and biofilm formation under precisely controlled homogeneous laminar flow conditions. Results Using Escherichia coli as the model bacterial strain, a microfluidic platform was developed to overcome several limitations of conventional microfluidics such as the lack of spatial control over bacterial colonization and allow label-free observation of bacterial proliferation at single-cell resolution. This platform was applied to demonstrate the influence of culture media on bacterial colonization and the consequent eradication of sessile bacteria by antibiotic. As expected, the nutrient-poor medium (modified M9 minimal medium) was found to promote bacterial adhesion and to enable a higher adhesion rate compared to the nutrient-rich medium (tryptic soy broth rich medium ). However, in rich medium the adhered cells colonized the glass surface faster than those in poor medium under otherwise identical conditions. For the first time, this effect was demonstrated to be caused by a higher retention of newly generated bacteria in the rich medium, rather than faster growth especially during the initial adhesion phase. These results also indicate that higher adhesion rate does not necessarily lead to faster biofilm formation. Antibiotic treatment of sessile bacteria with colistin was further monitored by fluorescence microscopy at single-cell resolution, allowing in situ analysis of killing efficacy of antimicrobials. Conclusion The platform established here represents a powerful and versatile tool for studying environmental effects such as medium composition on bacterial adhesion and biofilm formation. Our microfluidic setup shows great potential for the in vitro assessment of new antimicrobials and antifouling agents under flow conditions.

In Situ Microscopy for Real-time Determination of Single-cell Morphology in Bioprocesses

10.3791/57823 ◽  
2019 ◽  
Author(s):  
Anna Maria Marbà-Ardébol ◽  
Joern Emmerich ◽  
Michael Muthig ◽  
Peter Neubauer ◽  
Stefan Junne
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Cell Morphology ◽  
Time Determination

A microchip integrating cell array positioning with in situ single-cell impedance measurement

The Analyst ◽  
2015 ◽  
Vol 140 (19) ◽  
pp. 6571-6578 ◽  
Author(s):  
Xiaoliang Guo ◽  
Rong Zhu ◽  
Xianli Zong
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Impedance Measurement ◽  
Cell Array ◽  
Cell Impedance ◽  
Long Time ◽  
Cell Positioning

A micro-chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell using nano-modified measuring electrodes.

scholarly journals A Microfluidic Platform for in Situ Investigation of Biofilm Formation and Its Treatment Under Controlled Conditions

2020 ◽  
Author(s):  
Hervé Straub ◽  
Leo Eberl ◽  
Manfred Zinn ◽  
René M Rossi ◽  
Katharina Maniura-Weber ◽  
...  
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Rich Medium ◽  
Flow Conditions ◽  
Microfluidic Platform ◽  
Adhesion Rate

Abstract Background Studying bacterial adhesion and early biofilm development is crucial for understanding the physiology of sessile bacteria and forms the basis for the development of novel antimicrobial biomaterials. Microfluidics technologies can be applied in such studies since they permit dynamic real-time analysis and a more precise control of relevant parameters compared to traditional static and flow chamber assays. In this work, we aimed to establish a microfluidic platform that permits real-time observation of bacterial adhesion and biofilm formation under precisely controlled homogeneous laminar flow conditions. Results Using Escherichia coli as the model bacterial strain, a microfluidic platform was developed to overcome several limitations of conventional microfluidics such as the lack of spatial control over bacterial colonization and allow label-free observation of bacterial proliferation at single-cell resolution. This platform was applied to demonstrate the influence of culture media on bacterial colonization and the consequent eradication of sessile bacteria by antibiotic. As expected, the nutrient-poor medium was found to promote bacterial adhesion and to enable a higher adhesion rate compared to the nutrient-rich medium. However, in rich medium the adhered cells colonized the glass surface faster than those in poor medium under otherwise identical conditions. For the first time, this effect was demonstrated to be caused by a higher retention of newly generated bacteria in the rich medium, rather than faster growth especially during the initial adhesion phase. These results also indicate that higher adhesion rate does not necessarily lead to faster biofilm formation. Antibiotic treatment of sessile bacteria with colistin was further monitored by fluorescence microscopy at single-cell resolution, allowing in situ analysis of killing efficacy of antimicrobials.Conclusion The platform established here represents a powerful and versatile tool for studying environmental effects such as medium composition on bacterial adhesion and biofilm formation. Our microfluidic setup shows great potential for the in vitro assessment of new antimicrobials and antifouling agents under flow conditions.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

In-Situ Dual Beam (FIBSEM) Techniques for Probe Pad Deposition and Dielectric Integrity Inspection in 0.2 μm Technology DRAM Single Cells

1999 ◽  
Author(s):  
Gunnar Zimmermann ◽  
Richard Chapman
Keyword(s):  
Electron Beam ◽  
Single Cell ◽  
Single Cells ◽  
Ion Beam ◽  
Gate Oxide ◽  
Ion Milling ◽  
Dual Beam ◽  
Sem Imaging ◽  
Innovative Techniques

Abstract Dual beam FIBSEM systems invite the use of innovative techniques to localize IC fails both electrically and physically. For electrical localization, we present a quick and reliable in-situ FIBSEM technique to deposit probe pads with very low parasitic leakage (Ipara &lt; 4E-11A at 3V). The probe pads were Pt, deposited with ion beam assistance, on top of highly insulating SiOx, deposited with electron beam assistance. The buried plate (n-Band), p-well, wordline and bitline of a failing and a good 0.2 μm technology DRAM single cell were contacted. Both cells shared the same wordline for direct comparison of cell characteristics. Through this technique we electrically isolated the fail to a single cell by detecting leakage between the polysilicon wordline gate and the cell diffusion. For physical localization, we present a completely in-situ FIBSEM technique that combines ion milling, XeF2 staining and SEM imaging. With this technique, the electrically isolated fail was found to be a hole in the gate oxide at the bad cell.

Sign in / Sign up

Export Citation Format

Share Document