Search results for "Microfluidics"
showing 10 items of 121 documents
Distributed and Lumped Parameter Models for the Characterization of High Throughput Bioreactors
2016
Next generation bioreactors are being developed to generate multiple human cell-based tissue analogs within the same fluidic system, to better recapitulate the complexity and interconnection of human physiology. The effective development of these devices requires a solid understanding of their interconnected fluidics, to predict the transport of nutrients and waste through the constructs and improve the design accordingly. In this work, we focus on a specific model of bioreactor, with multiple input/outputs, aimed at gen- erating osteochondral constructs, i.e., a biphasic construct in which one side is cartilagi- nous in nature, while the other is osseous. We next develop a general computat…
Microscale Marangoni actuation: All-optical and all-electrical methods
2006
We present experimental results from an all-optical microfluidic platform that may be complimented by a thin film all-electrical network. Using these configurations we have studied the microfluidic convective flow systems of silicone oil, glycerol, and 1,3,5-trinitrotoluene on open surfaces through the production of surface tension gradients derived from thermal gradients. We show that sufficient localized thermal variation can be created utilizing surface plasmons and/or engaging individually addressable resistive thermal elements. Both studies manipulate fluids via Marangoni forces, each having their unique exploitable advantages. Surface plasmon excitation in metal foils are the driving …
Instabilités hydrodynamiques de fluides magnétiques en écoulements microfluidiques
2015
Advisors: Prof. Andrejs Cēbers (University of Latvia) & Prof. Régine Perzynski (University of Pierre and Marie Curie)
PRODUCTION VIA MICROFLUIDICS OF FIBRILLAR AND NANOMETRIC BIOMATERIALS FOR REGENERATIVE MEDICINE AND DRUG DELIVERY POURPOSES
2019
Microfluidic technique offers mild operating conditions suitable for fabrication of fibers and cell encapsulation and can be applied for controlled production of nanometric biomaterials1 . Ionotropic polysaccharides are routinely employed for microfluidics. To be processed, nonionotropic polysaccharides, such as Hyaluronic Acid (HA), should be chemically crosslinked during fabrication2 . In order to avoid chemical crosslinking, we designed an ionic strenght sensible HA derivative suitable for microfluidics2 . Here we describe the use of such HA derivative for fabrication of fibrillar and nanometric biomaterials for regenerative medicine and drug delivery applications. For muscle tissue rege…
Full in vitro fertilization laboratory mechanization: toward robotic assisted reproduction?
2011
Objective To describe the current efforts made to standardize different steps of assisted reproductive technology processes by the introduction of new technologies for the nonsubjective sperm selection process, oocyte denudation by mechanical removal of cumulus cells, oocyte positioning, sperm motility screening, fertilization, embryo culture, media replacement by microfluidics, and monitoring of embryo development by time-lapse photography, embryo secretions, and/or O 2 consumption. These technologies could be integrated in a unique and fully automated device. Design Pubmed database and research and development data from authors. Setting University-affiliated private center. Patient(s) Non…
Slip Flow Over Structured Surfaces with Entrapped Microbubbles
2008
On hydrophobic surfaces, roughness may lead to a transition to a superhydrophobic state, where gas bubbles at the surface can have a strong impact on a detected slip. We present two-phase lattice Boltzmann simulations of a Couette flow over structured surfaces with attached gas bubbles. Even though the bubbles add slippery surfaces to the channel, they can cause negative slip to appear due to the increased roughness. The simulation method used allows the bubbles to deform due to viscous stresses. We find a decrease of the detected slip with increasing shear rate which is in contrast to some recent experimental results implicating that bubble deformation cannot account for these experiments.…
Microfluidic Preparation of Liquid Crystalline Elastomer Actuators
2018
This paper focuses on the microfluidic process (and its parameters) to prepare actuating particles from liquid crystalline elastomers. The preparation usually consists in the formation of droplets containing low molar mass liquid crystals at elevated temperatures. Subsequently, these particle precursors are oriented in the flow field of the capillary and solidified by a crosslinking polymerization, which produces the final actuating particles. The optimization of the process is necessary to obtain the actuating particles and the proper variation of the process parameters (temperature and flow rate) and allows variations of size and shape (from oblate to strongly prolate morphologies) as wel…
Microactuators: Control of the Properties of Micrometer Sized Actuators from Liquid Crystalline Elastomers Prepared in a Microfluidic Setup (Adv. Fun…
2010
In this article new results on the preparation of monodisperse particles from a liquid crystalline elastomer in a microfluidic setup are presnted. For this, droplets from a liquid crystalline monomer are prepared in a microfluidic device and polymerized while they are flowing inside a microtube. The particles obtained by this method possess an internal orientation, which gives them actuating properties. When they are heated into the isotropic phase of the liquid crystalline material they show a reversible change in shape whereby they change their length in one direction by almost 100%. It is shown how the variation of experimental parameters during their synthesis impacts the properties of…
Microfluidic synthesis of micrometer-sized photoresponsive actuators based on liquid crystalline elastomers
2016
The fabrication of photoresponsive micrometer-sized liquid crystalline elastomer (LCE) particles has been described in this article for the first time. The preparation of the LCE particles using a microfluidic device by a continuous “on the fly” technique allows their fast processing with an irradiation time of less than 2 seconds. In order to accelerate the polymerization and to make the preparation of samples with thicknesses of several hundred microns possible, we modified a NIR-photoinitiation system by adding a bleaching agent. In addition to the photoinitiator, a side-chain liquid crystalline monomer containing an azo-group and a LC-crosslinker were used in the polymerization mixture.…
Transport of Water and Particles in Microfluidics Devices Lithographically Fabricated Using Proton Beam Writing (PBW)
2009
Proton beam writing (PBW) is a MeV ion beam lithography technique that has gained interest in many biological applications such as fabricating microfluidic devices for Lab-On-a-Chip (LOC) applications where capillary forces are important for fluid flow. PBW has a unique capability of being able to direct-write patterns in thick (1-30µm) polymer resist layers with straight vertical sidewalls. It can be used to prepare master stamps and moulds for mass production in polymeric materials. A recent development, where the direct writing of an entire pattern element is carried out in parallel makes PBW especially well suited for Bio-MEMS LOC applications. In this study we have examined the flow dy…