Microfluidics

The aim of the research project is to characterise a 2D single-cell analysis arrangement based on surface acoustic waves (SAW). For the first time, the position of the cells, the flow velocity of the surrounding liquid and the local temperature distribution will be analysed using novel, high-resolution measurement techniques in order to obtain detailed findings on the influence of high-frequency sound waves (>100 MHz) on liquids and the corpuscular components (particles, cells) suspended in them. Experimental characterisation of the SAW fields in the fluid-loaded microchamber using laser Doppler vibrometry and measurements of the velocity and temperature distribution using APTV will be used to specifically investigate microacoustic, flow and thermodynamic issues and highlight their interdependencies. This will be supported by the development of models for the numerical simulation of local pressure and flow gradients. Based on the results, it should be possible in future to derive design and application criteria for a 2D single-cell analysis arrangement that not only ensure stable operation of the arrangement but also promise low mechanical and thermal stress on the cells in long-term tests.

Funding organisations: DFG

Associate:

Leibniz Institut für Festkörper und Werkstoffforschung (IFW) Dresden

Processor:

• Prof. Dr.-Ing. Christian Cierpka (Project leader)
• Dr.-Ing. Jörg König (Project leader)
• Zhichao Deng (Processor)

Publications:

Z. Deng, Vijay V. Kondalkar, C. Cierpka, Hagen Schmidt, J. König (2023) From rectangular to diamond shape: on the three-dimensional and size-dependent transformation of patterns formed by single particles trapped in microfluidic acoustic tweezers Lab on a Chip 23, 2154 - 2160

Z. Deng, J. König, C. Cierpka (2022) A combined velocity and temperature measurement with an LED and a low-speed camera, Measurement Science and Technology 33. 115301  

R. Weser, Z. Deng, V. Kondalkar, S. Darinskii, H. Schmidt, C. Cierpka, J. König (2022) Three-dimensional heating and patterning dynamics of particles in microscale acoustic tweezers, Lab on a Chip 22, 2886-2901 

Z. Deng. V. Kondalkar, R. Weser, H. Schmidt, C. Cierpka, J. König: Experimentelle Untersuchung eines SAW-Systems zur Parallelanalyse einzelner Zellen. Tagungsband der 28. GALA-Fachtagung "Experimentelle Strömungsmechanik", 7.-9. September 2021, Bremen, Herausgeber: Fischer, A., Stöbener, D., Vanselow, C., Ruck, B., Leder, A., ISBN 978-3-9816764-7-1

J. Massing, J. König, F. Kiebert, S. Wege, H. Schmidt, C. Cierpka: 3D3C Geschwindigkeitsmessungen mittels Astigmatism Particle Tracking Velocimetry (APTV) in SAW-basierten mikrofluidischen Mischern, Fachtagung "Lasermethoden in der Strömungsmesstechnik, 08.-10.09.2015, Dresden, Germany

F. Kiebert, J. König, J. Massing, C. Cierpka, H. Schmidt (2017) 3D measurement and simulation of surface acoustic wave driven fluid motion: a comparison, Lab on a Chip 17, 2104-2114

In microfluidic reactors and heat exchangers, it is often necessary to simultaneously measure the three-dimensional flow and temperature field with time resolution in order to draw conclusions about the fundamental physical phenomena. With astigmatism PTV, velocity determination is based on the three-dimensional tracking of particles in the measurement volume. The basic principle is the encoding of the depth position of the particles via optical distortions using an additional cylindrical lens in the observation optics. If particles loaded with a temperature-sensitive dye are used for the measurement, the fluorescence signal can also be used to determine the temperature. The aim of this research project is therefore to improve the signal-to-noise ratio of the measurement technology and to use it for microfluidic heat exchangers with nanofluids and other complex microfluidic components.

Partner:

Universität der Bundeswehr München

Associates:

• Prof. Dr.-Ing. Christian Cierpka (Projektleiter)
• Dr. Jörg König (Projektleiter)
• Zhichao Deng (Bearbeiter)
   

Publications:

S. Sachs, Manuel Ratz, Patrick Mäder, J. König, C. Cierpka (2023) Particle detection and size recognition based on defocused particle images: a comparison of a deterministic algorithm and a deep neural network, Exp Fluids 64, 21

Z. Deng, J. König, C. Cierpka (2022) A combined velocity and temperature measurement with an LED and a low-speed camera, Measurement Science and Technology 33. 115301  

J. Massing, N. van der Schoot, C. J. Kähler, C. Cierpka (2019) A fast start up system for microfluidic direct methanol fuel cells, International Journal of Hydrogen Energy 44, 26517-26529, DOI: 10.1016/j.ijhydene.2019.08.107

J. Massing, C.J. Kähler, C. Cierpka (2018) A volumetric temperature and velocity measurement technique for microfluidics based on luminescence lifetime imaging, Experiments in Fluids 59, 163

X. Yang, D. Baczyzmalski, C. Cierpka, G. Mutschke, K. Eckert (2018) Marangoni convection at electrogenerated hydrogen bubbles, Physical Chemistry Chemical Physics 20, 11542

J. Massing, D. Kaden, C.J. Kähler, C. Cierpka (2016) Luminescent two-color tracer particles for simultaneous velocity and temperature measurements in microfluidics, Measurement Science and Technology 27, 1153014

R. Segura, M. Rossi, C. Cierpka, C.J. Kähler (2015) Simultaneous three-dimensional temperature and velocity field measurements using astigmatic imaging of non-encapsulated thermo-liquid crystal (TLC) particles. Lab on a Chip 15, 660-663

The magnetohydrodynamic conversion of kinetic energy of fluids into electric energy is well known and applied for power generation. A recent experiment shows a similarity between the magnetic field and the spin-orbit orientation in liquid metals, which opens a completely undiscovered path for energy conversion. This promising technique, known as spin hydrodynamic generation, relies on a coupling between the flow vorticity and electron spins to generate electricity with no needs of any external magnetic field. The spin hydrodynamic generation, however, is in its early infancy stage and many unresolved questions need to be addressed to enhance our understanding of how the macroscopic hydrodynamic world couples with the spin-orbitals on atomistic levels. In this regard, an experimental setup consisting of a large box to control the environmental conditions, a pressure vessel which is filled with the eutectic alloy Indium-Gallium-Tin (GaInSn), and connecting circular and non-circular capillary tubes was built. When a pressure (up to 10 bar) is applied the liquid metal is pushed through the capillary into another storage vessel placed on a high precision scale to determine the mass flow rate. The electrical potential is then measured between the electrodes at the beginning and at the end of the capillary. The primarily experimental results show a significant agreement with previous studies in the same range of the flow Reynolds number. For the extended range to lower and higher Reynolds numbers, measurements have provided compelling evidence for the validity of the proposed theories describing the generated electrical voltage via the spin-vorticity coupling.

Despite the first successful experiments, there is still a great need for a very good control of many parameters. Rigorous investigation of the concept could alter our perception of spintronics and our way of electric energy production completely.

Funding: Volkswagen Foundation                     

Partner:

• Prof. Dr. Jörg Schumacher

Project staff:

• Prof. Dr.-Ing. Christian Cierpka

• Dr. Hamid Tabaei Kazerooni

Publications:

H. Tabaei Kazerooni, A. Thieme, J. Schumacher, C. Cierpka (2020) Electron spin-vorticity coupling in low and high Reynolds number pipe flows, Physical Review Applied, accepted for publication (preprint on arxiv)