סמינר מחלקה - של גלעד יוסיפון

13 ביוני 2021, 15:00 - 15:00 
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סמינר מחלקה של גלעד יוסיפון

 

 

"ZOOM" SEMINAR

School of Mechanical Engineering Seminar
Monday, June 13 2021 at 14.00

Non-linear Electrokinetic Phenomena in
Micro- and Nano-Fluidic Devices

 

Prof. Gilad Yossifon

Current affiliation: Faculty of Mechanical Engineering, Micro- and Nanofluidics Laboratory, Technion – Israel Institute of Technology, Haifa 32000, Israel;

Future affiliation --- Starting October 2021 --- School of Mechanical Engineering, µ/Nano-Fluidics and µ/Nano-Robots Laboratory, University of Tel-Aviv

gilad.yossifon@gmail.com, https://mnfl.technion.ac.il/

 

Electrokinetics (the use of electric fields to impart a force on liquids and particles) promises to be the technique of choice for many portable and miniaturized micro- and nano-fluidic based devices, e.g. lab-on-a-chip, point-of-care and wearable devices. Under alternating current electric fields, non-linear electrokinetic phenomena have a non-vanishing time-averaged effect. At sufficiently high frequencies Faradaic effects are suppressed, thus enabling embedding of actuating electrodes within the microchannel itself. Thus, nonlinear electrokinetic effects, besides their fundamental scientific importance, are ideal for practical tasks such as net pumping, mixing, and manipulation of particles in lab-on-a-chip devices. The talk reviews two major examples of these effects -- ion transport through ion-permselective nanochannels/membranes and induced-charge electrokinetics. Fabricated nanochannel systems share a number of similarities with the older and more well-known field of ion-selective membranes, but it may be the differences which have the most applicative and fundamental scientific importance. Understanding the various effects occurring in these different systems is of particular interest for applications such as pre-concentration of analytes, electrodialysis, electroconvective mixing, and biomolecular detection. Another non-linear phenomenon occurs at polarizable surfaces, where the external electric field acts on the diffuse ionic charge cloud induced by the field itself. This effect termed, induced-charge electrokinerics, combined with introduction of an asymmetry into the system, results in net motion for active particles and control of their direction and alignment enabling their implementation as carriers in chemical and biological analysis system. Such mobile active (self-propelling) particles (also known as “micro-motors” and “micro-robots”) are expected to significantly advance lab-on-a-particle platforms for diagnostic testing and sample analysis; with advantages of the traditional lab-on-a-chip (e.g. portability, efficiency) but overcoming current challenges (e.g. complexity, predetermined design, fluid control). Lastly, it will be shown that fundamental understanding of microfluidics and non-linear electrokinetic actuation/characterization methods can be utilized for novel practical applications, including single cell screening and analysis, multiplex biosensing etc.

 

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https://us02web.zoom.us/j/82108132163?pwd=Z2h4UzNzUS9mbXplT0lMU1pZenFEQT09

 

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