scholarly journals An optofluidic “tweeze-and-drag” cell stretcher in a microfluidic channel

Lab on a Chip ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 601-613 ◽  
Author(s):  
Zhanshi Yao ◽  
Ching Chi Kwan ◽  
Andrew W. Poon
Keyword(s):  
Mechanical Characterization ◽  
Microfluidic Channel ◽  
Optical Tweezer ◽  
Microfluidic Flow ◽  
Cell Stretcher

An optofluidic cell stretcher using a periodically chopped optical tweezer and a microfluidic flow for non-contact, continuous cell mechanical characterization.

Modeling Nanomechanical Strains in Healthy and Diseased Single-Cells Due to Applied Fluidic Stresses

2010 ◽  
Author(s):  
Zachary D. Wilson ◽  
Sean S. Kohles
Keyword(s):  
Single Cells ◽  
Microfluidic Channel ◽  
Optical Tweezer ◽  
Cellular Level ◽  
Image Velocimetry ◽  
Integrated Optical ◽  
Stress Profiles ◽  
Spherical Cells ◽  
The Relationship ◽  
Applied Stresses

Advancements in technologies for assessing biomechanics at the cellular level have led to discoveries in the relationship between mechanics and biology (mechanotransduction) and the investigation of cell mechanics as a biomarker for disease [1]. With the recent development of an integrated optical tweezer with micron resolution particle image velocimetry (436 nm spatial resolution), the opportunity to apply controlled multiaxial stresses to suspended single cells is available [2]. A stress analysis was applied to experimental and theoretical flow velocity gradients of suspended cell-sized polystyrene microspheres in microfluidic environments representing the relevant geometry of non-adhered spherical cells as observed for osteoblasts, chondrocytes, and fibroblasts [3]. That analysis identified a very low level of applied stresses available during creeping laminar flow within straight and cross-junction microfluidic channel arrangements with uniform and extensional flows, respectively. As a followup study, the objective here was to apply a range of normal and shear stress profiles in a two-dimensional, computational analysis and estimate the responding cellular strains.

A Fully Integrated System for Cell/Particle Sorting in a Microfluidic Device Utilizing an Optical Tweezing and DIP Recognition Approach

2006 ◽  
Vol 505-507 ◽  
pp. 643-648 ◽  
Author(s):  
Yu Sheng Chien ◽  
Che Hsin Lin ◽  
Fu Jen Kao ◽  
Cheng Wen Ko
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Microfluidic Device ◽  
Digital Image ◽  
Microfluidic Channel ◽  
Optical Tweezer ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Target Cells ◽  
Digital Image Processing Technique

This paper proposes a novel microfluidic system for cell/microparticle recognition and manipulation utilizing a digital image processing technique (DIP) controlled optical tweezer under microfluidic configuration. Cell/microparticle samples are firstly electrokinetically sorted in a microfluidic channel and pass through an image detection region. Digital image processing technique is used to count and recognize the cell/particle samples and then sends control signals to generate laser pulses to manipulate the target cell/particles optically. The optical tweezer system is capable of catching, moving and switching the target cells within the microfluidic channel. The trapping force of the optical tweezer is also demonstrated utilizing the relationship between Stocks-drag force of microparticles and the applied electroosmotic flow. The proposed system provides a simple but high-performance solution for microparticle manipulation in a microfluidic device.

Microfluidic Flow Control Using Induced-Charge Electroosmosis

2008 ◽  
Author(s):  
Kendra V. Sharp ◽  
Scott M. Davison ◽  
Shahrzad H. Yazdi
Keyword(s):  
Electric Field ◽  
Electroosmotic Flow ◽  
Microfluidic Channel ◽  
Microfluidic System ◽  
Ac Electric Field ◽  
Microfluidic Flow ◽  
Or Groups ◽  
Dc Electric Field ◽  
Induced Charge ◽  
Fixed Region

Work with dc electrokinetics has demonstrated that is works well for bulk transport of fluid an particles. However, it is difficult to achieve control of individual or groups of particles. This paper investigate the use of induced-charge electroosmosis (ICEO) as a means of providing control over particles within bulk dc electroosmotic flow. ICEO flow develops when an electric double layer is induced by an applied electric field at the surface of a conducting object. Here conducting posts are positioned in a microfluidic channel and ICEO flow develops around them due to an applied ac electric field. A dc electric field is applied across the length of the channel to induce electroosmotic flow past the ICEO region. Around one arrangement of posts the ac and dc flow fields combine to produce a region of recirculation which could be useful for holding a particle or particles within a fixed region of the channel. An alternative arrangement of posts functions to focus the flow into the center of the channel. A numerical model of the system is developed and used to explore means of adapting the ICEO flows to many situations. A method for fabricating a microfluidic system for ICEO flows is presented.

scholarly journals Microfluidic Portable Device for Pathogens’ Rapid SERS Detection

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 2
Author(s):  
Nicoleta Elena Dina ◽  
Alia Colniță ◽  
Daniel Marconi ◽  
Ana Maria Raluca Gherman
Keyword(s):  
Microfluidic Device ◽  
Microfluidic Channel ◽  
Flow Cell ◽  
Microfluidic Flow ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Active Substrate ◽  
Total Analysis ◽  
Main Components ◽  
User Friendly

So far, in some of our previous works, we have managed to rapidly (within minutes) identify and discriminate pathogens by using surface-enhanced Raman scattering (SERS) spectroscopy with a single cell sensitivity. Having a more user friendly and robust system, which could be used not only by experts, would be the next step. In order to meet our goal, we developed an experimental setup, including an in-house built microfluidic device and we optimized the SERS detection of common bacterial pathogens by using the developed device. The main components of the system are a microfluidic flow-cell coupled to a syringe pump mediated flow system and a portable Raman spectrometer for detecting the bacteria immobilized in the flow cell. Inside the microfluidic channel of the flow cell, a silver spot was generated under laser irradiation for further use as SERS active substrate for detection. The silver spot can be washed and reused for a different pathogen from one experiment to another. No specific capturing receptors are used. The total analysis time was reduced to less than 15 min. Considering the fit-for-purposes experimental parameters for detection and its easy-to-use dedicated software, this portable microfluidic device has been tested in our lab and is ready to be transferred in the research/clinical premises for further use.

Improved micro-impedance spectroscopy to determine cell barrier properties

2020 ◽  
Vol 4 (3) ◽  
pp. 150-155 ◽  
Author(s):  
Md. Mehadi Hasan Sohag ◽  
Olivier Nicoud ◽  
Racha Amine ◽  
Abir Khalil-Mgharbel ◽  
Jean-Pierre Alcaraz ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Epithelial Cells ◽  
Lipid Bilayers ◽  
Cultured Cells ◽  
Cell Model ◽  
Measurement Techniques ◽  
Cell Monolayer ◽  
Microfluidic Channel ◽  
Small Surface ◽  
Resistance Pathway

AbstractThe goal of this study was to determine whether the Tethapod system, which was designed to determine the impedance properties of lipid bilayers, could be used for cell culture in order to utilise micro-impedance spectroscopy to examine further biological applications. To that purpose we have used normal epithelial cells from kidney (RPTEC) and a kidney cancer cell model (786-O). We demonstrate that the Tethapod system is compatible with the culture of 10,000 cells seeded to grow on a small area gold measurement electrode for several days without affecting the cell viability. Furthermore, the range of frequencies for EIS measurements were tuned to examine easily the characteristics of the cell monolayer. We demonstrate significant differences in the paracellular resistance pathway between normal and cancer kidney epithelial cells. Thus, we conclude that this device has advantages for the study of cultured cells that include (i) the configuration of measurement and reference electrodes across a microfluidic channel, and (ii) the small surface area of 6 parallel measurement electrodes (2.1 mm2) integrated in a microfluidic system. These characteristics might improve micro-impedance spectroscopy measurement techniques to provide a simple tool for further studies in the field of the patho-physiology of biological barriers.

Spectro-mechanical Characterization of Aromaticity and Maturity of Kerogens in Oil Shale at 6 nm Spatial Resolution

2018 ◽  
Author(s):  
Devon Jakob ◽  
Le Wang ◽  
Haomin Wang ◽  
Xiaoji Xu
Keyword(s):  
Spatial Resolution ◽  
Oil Shale ◽  
Infrared Imaging ◽  
Mechanical Characterization ◽  
Optical Diffraction ◽  
Chemical Compositions ◽  
Valuable Insight ◽  
Eagle Ford Shale

<p>In situ measurements of the chemical compositions and mechanical properties of kerogen help understand the formation, transformation, and utilization of organic matter in the oil shale at the nanoscale. However, the optical diffraction limit prevents attainment of nanoscale resolution using conventional spectroscopy and microscopy. Here, we utilize peak force infrared (PFIR) microscopy for multimodal characterization of kerogen in oil shale. The PFIR provides correlative infrared imaging, mechanical mapping, and broadband infrared spectroscopy capability with 6 nm spatial resolution. We observed nanoscale heterogeneity in the chemical composition, aromaticity, and maturity of the kerogens from oil shales from Eagle Ford shale play in Texas. The kerogen aromaticity positively correlates with the local mechanical moduli of the surrounding inorganic matrix, manifesting the Le Chatelier’s principle. In situ spectro-mechanical characterization of oil shale will yield valuable insight for geochemical and geomechanical modeling on the origin and transformation of kerogen in the oil shale.</p>

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