University of Groningen
Microfluidic particle trapping and separation using combined hydrodynamic and electrokinetic
effects
Fernandez Poza, Sergio
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Publication date: 2019
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Fernandez Poza, S. (2019). Microfluidic particle trapping and separation using combined hydrodynamic and electrokinetic effects. University of Groningen.
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.
PhD Thesis
Microfluidic particle trapping and
separation using combined hydrodynamic
and electrokinetic effects
.
Paranymphs:
Dr. Hector J. García de Marina Dr. Javier Moldón Vara
Cover design: Lovebird design © Layout design: Sergio Fernández Poza Printed by: Eikon +
The research presented in this thesis was financially supported by the European Commission in the framework of the Marie Curie actions, project SAMOSS (Sample-in Answer-Out Optochemical Systems) and the University of Groningen. Printing of this thesis was supported by the University of Groningen, Faculty of Science and Engineering and the University Library.
ISBN (printed version): 978-94-034-1482-9 ISBN (digital version): 978-94-034-1481-2
No parts of this thesis may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system, without permission of the author.
Supervisors
Prof. E. Verpoorte Prof. T.I.F.H. Cremers
Assessment committee
Prof. T. Laurell Prof. J. Eijkel Prof. P. Onck
Contents
1 General introduction and scope of this thesis 1
1.1 Introduction to microfluidics . . . 1
1.2 Scaling down fluidic systems . . . 3
1.2.1 Fluid motion and Navier-Stokes equation . . . 3
1.2.2 Flow profiles and other electrokinetic effects . . . 4
1.2.2.1 Pressure-driven flow . . . 4
1.2.2.2 Electro-osmotic flow . . . 5
1.2.2.3 Electrophoresis . . . 7
1.3 Introduction to microfabrication techniques employing rigid substrates . 7 1.3.1 Wet etching . . . 8
1.3.2 Dry etching . . . 8
1.4 Scope of this thesis . . . 9
Bibliography 10 2 Electrokinetic strategies for particle sorting and separation in microfluidics 13 2.1 Introduction . . . 13
2.2 Electrokinetic techniques based on electrophoretic and electro-osmotic phenomena . . . 15
2.2.1 General principles . . . 15
2.2.2 Particle separations based on combined electrophoresis and electro-osmosis . . . 17
2.2.3 Separations based on combined electrokinetic and hydrodynamic forces . . . 22
2.2.4 Separations based on electrophoresis and channel obstacles . . . 26
2.3 Dielectrophoresis . . . 28
2.3.1 General principles . . . 28
2.3.2 AC-field dielectrophoresis . . . 30
2.3.2.1 Recent electrode designs in AC-DEP . . . 32
2.3.2.2 Contactless AC-DEP . . . 37
2.3.2.3 AC-DEP single cell handling . . . 41
2.3.3 DC-field dielectrophoresis . . . 41
2.3.4 Other DEP-based strategies . . . 47
2.3.4.1 DEP-FFF . . . 47
2.3.4.2 Traveling-wave dielectrophoresis . . . 50
2.4 Concluding remarks . . . 51
Bibliography 53 3 Characterizing particle enrichment using combined hydrodynamic and electrokinetic phenomena 65 3.1 Introduction . . . 65
3.2 Theory . . . 67
3.3 Materials and methods . . . 69
3.3.1 Design and fabrication . . . 69
3.3.1.1 Wet etching of the channels . . . 69
3.3.1.2 Cover plate preparation . . . 70
3.3.1.3 Pre-bonding treatment . . . 70
3.3.1.4 Fusion bonding . . . 70
3.3.1.5 Attachment of the reservoirs . . . 71
3.3.2 Polymer microparticles and flow generation . . . 71
3.3.3 Running conditions for trapping experiments . . . 72
3.3.4 Particle observation . . . 72
3.4 Results and discussion . . . 73
3.4.1 Particle distribution . . . 73
3.4.2 Characterization of particle distributions at different ΔP . . . . 76
3.4.3 Quantitative particle trapping and preconcentration . . . 77
3.5 Conclusions . . . 80
Bibliography 83 4 Optimizing size- and charge-based particle fractionations in microchannels using Flow-Induced Electrokinetic Trapping 86 4.1 Introduction . . . 87 4.2 Experimental . . . 88 4.2.1 Microchip fabrication . . . 88 4.2.2 Flow generation . . . 89 4.2.3 Polymer particles . . . 90 4.2.4 Experimental conditions . . . 90
4.3 Theory . . . 91
4.3.1 Trapping process in FIET . . . 91
4.3.2 Particle distribution and characterization of the trapping process in the channel . . . 92
4.4 Results and discussion . . . 94
4.4.1 Fractionation of particles with different size . . . 94
4.4.2 Fractionation of particles with different charge . . . 97
4.4.3 Evaluation of particle fractions exiting the separation channel . . 99
4.5 Conclusions . . . 101
Bibliography 103 5 Simultaneous microfluidic size- and charge-based fractionation of polymer microparticles using recirculating flows 106 5.1 Introduction . . . 107
5.2 Experimental . . . 109
5.2.1 Microchip fabrication and setup . . . 109
5.2.2 Particle suspensions . . . 110
5.2.3 Flow generation and particle trapping effect . . . 111
5.2.4 Detection of particles . . . 111
5.3 Theory . . . 112
5.3.1 Particle velocity in separation segment under bidirectional flow conditions . . . 112
5.3.2 Particle fractionation . . . 113
5.4 Results . . . 114
5.4.1 Particle distribution curves at different applied pressures . . . 114
5.4.2 Simultaneous size- and charge-based particle fractionation . . . . 117
5.5 Conclusions . . . 121
Bibliography 122 6 Concluding remarks 126 6.1 General discussion and conclusions . . . 126
6.2 Outlook and future perspectives . . . 129
Bibliography 131
Summary (English) 134
Resumen (Español) 138
