Optical Manipulation of Inorganic and Organic Objects in Soft Microfluidic Devices

2000 ◽  
Vol 657 ◽  
Author(s):  
Cengiz S. Ozkan ◽  
Erhan Ata ◽  
Mihrimah Ozkan ◽  
Sadik C. Esener
Keyword(s):  
Optical Tweezers ◽  
Cell Sorting ◽  
Cell Biology ◽  
Microfluidic Devices ◽  
Optical Manipulation ◽  
Microfluidic Channels ◽  
Negative Photoresist ◽  
Pdms Elastomer ◽  
Biology Research ◽  
Inorganic And Organic

ABSTRACTWe describe a technique for trapping and manipulation of inorganic and organic objects in microfluidic channels, based on photonic momentum transfer using an optical tweezers arrangement. Microfluidic devices have been fabricated by polydimethylsiloxane (PDMS) elastomer molding of patterns lithographically defined on a thick negative photoresist. Polystyrene microspheres dispersed in water were transferred into the fluidic channels using a syringe pump. Microspheres and live biological cells are trapped and redirected by optical manipulation within the fluidic channels. Optical trapping and patterning will have applications in creation of active cellular arrays for cell biology research, tissue engineering, cell sorting and drug discovery.

Optical Manipulation of Objects in Microfluidic Devices

2002 ◽  
Vol 729 ◽  
Author(s):  
Erhan Ata ◽  
Aaron L. Birkbeck ◽  
Mihrimah Ozkan ◽  
Cengiz S. Ozkan ◽  
Richard Flynn ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Optical Power ◽  
Microfluidic Devices ◽  
Live Cells ◽  
Optical Manipulation ◽  
Polystyrene Spheres ◽  
Pdms Elastomer ◽  
Photon Interactions ◽  
Vcsel Arrays

AbstractIn this paper, we present object manipulation methodologies in microfluidic devices based on object-photon interactions. Devices were fabricated by polydimethylsiloxane (PDMS) elastomer molding of channel structures over photolithographically defined patterns using a thick negative photoresist. Inorganic objects including polystyrene spheres and organic objects including live cells were transferred into fluidic channels using a syringe pump. The objects were trapped and manipulated within the fluidic channels using optical tweezers formed by VCSEL arrays, with only a few mW of optical power. We have also shown that it is possible to manipulate multiple objects as a whole assemble by using an optically-trapped particle as a handle, or an “optical handle”. Optical manipulation will have applications in biomedical devices for drug discovery, cytometry and cell biology research.

Hydrodynamically-Confined Microflows for Cell Adhesion Strength Measurement

2010 ◽  
Author(s):  
Kevin V. Christ ◽  
Kevin T. Turner
Keyword(s):  
Cell Adhesion ◽  
Adhesion Strength ◽  
Cell Biology ◽  
Microfluidic Devices ◽  
Cell Behavior ◽  
Shear Stresses ◽  
Strength Measurement ◽  
Coated Surfaces ◽  
Biology Research ◽  
Standard Techniques

Cell adhesion plays a fundamental role in numerous physiological and pathological processes, and measurements of the adhesion strength are important in fields ranging from basic cell biology research to the development of implantable biomaterials. Our group and others have recently demonstrated that microfluidic devices offer advantages for characterizing the adhesion of cells to protein-coated surfaces [1,2]. Microfluidic devices offer many advantages over conventional assays, including the ability to apply high shear stresses in the laminar regime and the opportunity to directly observe cell behavior during testing. However, a key disadvantage is that such assays require cells to be cultured inside closed microchannels. Assays based on closed channels restrict the types of surfaces that can be examined and are not compatible with many standard techniques in cell biology research. Furthermore, while techniques for cell culture in microchannels have become common, maintaining the viability of certain types of cells in channels remains a challenge.

An integrated inertial microfluidic vortex sorter for tunable sorting and purification of cells

TECHNOLOGY ◽  
2016 ◽  
Vol 04 (02) ◽  
pp. 88-97 ◽  
Author(s):  
Xiao Wang ◽  
Xiaodi Yang ◽  
Ian Papautsky
Keyword(s):  
Cell Sorting ◽  
Cell Biology ◽  
Human Cancer ◽  
Clinical Diagnostics ◽  
Target Cells ◽  
Label Free ◽  
Flow Conditions ◽  
Large Target ◽  
Fluidic Resistance ◽  
Biology Research

Sorting of target cells from complex cellular samples into a high-purity product is challenging yet essential for downstream cell biology research and clinical diagnostics. Inertial microfluidics is an emerging technology attracting a lot of interest for passive and label-free sorting of cells with high throughput. Here, we introduce an inertial microfluidic device based on our vortex sorting platform for continuous size-based double sorting and purification of the larger target cells from the smaller background cells. Our device uses a microscale chamber with three outlets as a sorting unit, and integrates it into a specific topology to enable double sorting and purification functionalities. With properly designed fluidic resistance network and optimized flow conditions, we demonstrated continuous sorting of spiked human cancer stem-like cells from human blood with >90% efficiency and >1,500× enhanced purity, as well as removal of red blood cells with ~99.97% efficiency. We envision this integrated vortex-aided sorter can serve as a viable tool for size-based sorting of large target cells from complex cellular samples. Furthermore, this vortex-aided sorting platform can be integrated into more sophisticated topology with versatile functions for other cell sorting applications.

Recent developments in microfluidic devices for in vitro cell culture for cell-biology research

2012 ◽  
Vol 35 ◽  
pp. 150-164 ◽  
Author(s):  
Dan Gao ◽  
Hongxia Liu ◽  
Yuyang Jiang ◽  
Jin-Ming Lin ◽  
Dan Gao ◽  
...  
Keyword(s):  
Cell Culture ◽  
Cell Biology ◽  
Microfluidic Devices ◽  
In Vitro Cell Culture ◽  
Recent Developments ◽  
Biology Research

scholarly journals Cell Biology of Conidial Anastomosis Tubes in Neurospora crassa

2005 ◽  
Vol 4 (5) ◽  
pp. 911-919 ◽  
Author(s):  
M. Gabriela Roca ◽  
Jochen Arlt ◽  
Chris E. Jeffree ◽  
Nick D. Read
Keyword(s):  
Neurospora Crassa ◽  
Optical Tweezers ◽  
Cell Biology ◽  
Transmembrane Protein ◽  
Mitogen Activated Protein Kinase ◽  
Cellular Element ◽  
Hyphal Fusion ◽  
Self Recognition ◽  
Mitogen Activated Protein ◽  
Germ Tubes

ABSTRACT Although hyphal fusion has been well documented in mature colonies of filamentous fungi, it has been little studied during colony establishment. Here we show that specialized hyphae, called conidial anastomosis tubes (CATs), are produced by all types of conidia and by conidial germ tubes of Neurospora crassa. The CAT is shown to be a cellular element that is morphologically and physiologically distinct from a germ tube and under separate genetic control. In contrast to germ tubes, CATs are thinner, shorter, lack branches, exhibit determinate growth, and home toward each other. Evidence for an extracellular CAT inducer derived from conidia was obtained because CAT formation was reduced at low conidial concentrations. A cr-1 mutant lacking cyclic AMP (cAMP) produced CATs, indicating that the inducer is not cAMP. Evidence that the transduction of the CAT inducer signal involves a putative transmembrane protein (HAM-2) and the MAK-2 and NRC-1 proteins of a mitogen-activated protein kinase signaling pathway was obtained because ham-2, mak-2, and nrc-1 mutants lacked CATs. Optical tweezers were used in a novel experimental assay to micromanipulate whole conidia and germlings to analyze chemoattraction between CATs during homing. Strains of the same and opposite mating type were shown to home toward each other. The cr-1 mutant also underwent normal homing, indicating that cAMP is not the chemoattractant. ham-2, mak-2, and nrc-1 macroconidia did not attract CATs of the wild type. Fusion between CATs of opposite mating types was partially inhibited, providing evidence of non-self-recognition prior to fusion. Microtubules and nuclei passed through fused CATs.

scholarly journals Biological cell-based screening for scientific membranal and cytoplasmatic markers using dielectric spectroscopy

2008 ◽  
Vol 2 (2) ◽  
pp. 111-121
Author(s):  
Ragini Raj Singh ◽  
◽  
Amit Ron ◽  
Nick Fishelson ◽  
Irena Shur ◽  
...  
Keyword(s):  
Cell Lines ◽  
Dielectric Spectroscopy ◽  
Cell Biology ◽  
Screening Tool ◽  
Excitation Frequency ◽  
Cell Physiology ◽  
Biological Cell ◽  
Non Invasive ◽  
Native Cell ◽  
Biology Research

Dielectric spectroscopy (DS) of living biological cells is based on the analysis of cells suspended in a physiological medium. It provides knowledge of the polarization-relaxation response of the cells to external electric field as function of the excitation frequency. This response is strongly affected by both structural and molecular properties of the cells and, therefore, can reveal rare insights into cell physiology and behaviour. This study demonstrates the mapping potential of DS after cytoplasmic and membranal markers for cell-based screening analysis. The effect of membrane permittivity and cytoplasm conductivity was examined using tagged MBA and MDCK cell lines respectively. The comparison of the dielectric spectra of tagged and native cell lines reveals clear differences between the cells. In addition, the differences in the matching dielectric properties of the cells were discovered. Those findings support the high distinction resolution and sensitivity of DS after fine molecular and cellular changes, and hence, highlight the high potential of DS as non invasive screening tool in cell biology research.

scholarly journals Hemodynamic forces can be accurately measured in vivo with optical tweezers

2017 ◽  
Author(s):  
Sébastien Harlepp ◽  
Fabrice Thalmann ◽  
Gautier Follain ◽  
Jacky G. Goetz
Keyword(s):  
Optical Tweezers ◽  
Cell Biology ◽  
Accurate Determination ◽  
Force Measurements ◽  
Hemodynamic Forces ◽  
Non Invasive ◽  
Drag Forces ◽  
Measured Flow ◽  
Living Organisms

AbstractForce sensing and generation at the tissular and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows non-invasive probing of pico-Newton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles rely in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here, we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether, this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.

scholarly journals Self-Aligned Interdigitated Transducers for Acoustofluidics

2016 ◽  
Author(s):  
Zhichao Ma ◽  
Adrian J. T. Teo ◽  
Say Hwa Tan ◽  
Ye Ai ◽  
Nam-Trung Nguyen
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Particle Separation ◽  
Microfluidic Devices ◽  
Current Approach ◽  
Droplet Generation ◽  
Microfluidic Channels ◽  
Clean Room ◽  
Precise Location ◽  
Innovative Method

Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

scholarly journals Eukaryotic systems broaden the scope of synthetic biology

2009 ◽  
Vol 187 (5) ◽  
pp. 589-596 ◽  
Author(s):  
Karmella A. Haynes ◽  
Pamela A. Silver
Keyword(s):  
Synthetic Biology ◽  
Nucleic Acids ◽  
Cell Biology ◽  
Cell Behavior ◽  
Cellular Functions ◽  
Complex Cells ◽  
Cellular Processes ◽  
Challenges And Opportunities ◽  
Foundational Work ◽  
Biology Research

Synthetic biology aims to engineer novel cellular functions by assembling well-characterized molecular parts (i.e., nucleic acids and proteins) into biological “devices” that exhibit predictable behavior. Recently, efforts in eukaryotic synthetic biology have sprung from foundational work in bacteria. Designing synthetic circuits to operate reliably in the context of differentiating and morphologically complex cells presents unique challenges and opportunities for progress in the field. This review surveys recent advances in eukaryotic synthetic biology and describes how synthetic systems can be linked to natural cellular processes in order to manipulate cell behavior and to foster new discoveries in cell biology research.

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