Beyond high voltage in the digital microfluidic devices for an integrated portable sensing system

  • Xin Min
  • Woo Soo KimEmail author


Digital microfluidics (DMFs) show great potential in the fields of lab-on-a-chip applications for electro-chemical as well as biochemical sensing for decades. Various types of DMF devices have been demonstrated to improve their capabilities such as smaller device size for portability, higher reliability, and multi-purpose applications, etc. Among them, the electrowetting on dielectric (EWOD) is one of the most widely used mechanisms to manipulate droplets due to its good flexibility. On the other hand, the high-voltage application that required for EWOD-type DMF also limits the portability and dimension of the whole system. In this review, we discuss the DMFs which are powered by alternative sources other than electrical sources and evaluate their potential for future portable biochemical assays. Then, the demonstrations reported with the possibility beyond high voltage are discussed starting from lowering voltage requirement for EWODs to the unique methods using mechanical, optical, and energy harvesting to power DMF devices. Finally, the practical applications and prospective on the integrated multi-functional lab-on-a-chip applications are tackled.


Digital microfluidics Portable platforms Sensing system Energy efficient 



  1. Abdelgawad M, Park P, Wheeler AR (2009) Optimization of device geometry in single-plate digital microfluidics. J Appl Phys. CrossRefGoogle Scholar
  2. Alghane M, Chen BX, Fu YQ et al (2011) Experimental and numerical investigation of acoustic streaming excited by using a surface acoustic wave device on a 128° YX-LiNbO3 substrate. J Micromech Microeng. CrossRefGoogle Scholar
  3. Alistar M, Gaudenz U (2017) OpenDrop: an integrated do-it-yourself platform for personal use of biochips. Bioengineering 4:45. CrossRefGoogle Scholar
  4. Baird E, Young P, Mohseni K (2007) Electrostatic force calculation for an EWOD-actuated droplet. Microfluid Nanofluidics 3:635–644. CrossRefGoogle Scholar
  5. Beebe DJ, Mensing GA, Walker GM (2002) Physics and applications of microfluidics in biology. Annu Rev Biomed Eng 4:261–286. CrossRefGoogle Scholar
  6. Berthier J (2013) Digital microfluidics micro-drops and digital microfluidics. ElsevierGoogle Scholar
  7. Berthier J, Peponnet C (2007) A model for the determination of the dimensions of dents for jagged electrodes in electrowetting on dielectric microsystems. Biomicrofluidics 1:1–9. CrossRefGoogle Scholar
  8. Berthier J, Dubois P, Clementz P et al (2007) Actuation potentials and capillary forces in electrowetting based microsystems. Sens Actuators A Phys 134:471–479. CrossRefGoogle Scholar
  9. Bertoni HL, Tamir T (1973) Unified theory of Rayleigh-angle phenomena for acoustic beams at liquid–solid interfaces. Appl Phys 2:157–172. CrossRefGoogle Scholar
  10. Beyssen D, Le Brizoual L, Elmazria O, Alnot P (2006) Microfluidic device based on surface acoustic wave. Sens Actuators B Chem 118:380–385. CrossRefGoogle Scholar
  11. Biswas S, Pomeau Y, Chaudhury MK (2016) New drop fluidics enabled by magnetic-field-mediated elastocapillary transduction. Langmuir 32:6860–6870. CrossRefGoogle Scholar
  12. Chang JH, Choi DY, You X et al (2010) Low voltage electrowetting on atomic-layer-deposited aluminum oxide. 2010 IEEE 5th Int Conf Nano/Micro Eng Mol Syst NEMS 2010. CrossRefGoogle Scholar
  13. Chen G, Liu X, Li S et al (2018) A droplet energy harvesting and actuation system for self-powered digital microfluidics. Lab Chip 18:1026–1034. CrossRefGoogle Scholar
  14. Chiou PY, Moon H, Toshiyoshi H et al (2003) Light actuation of liquid by optoelectrowetting. Sens Actuators A Phys 104:222–228. CrossRefGoogle Scholar
  15. Chiou CH, Jin Shin D, Zhang Y, Wang TH (2013) Topography-assisted electromagnetic platform for blood-to-PCR in a droplet. Biosens Bioelectron 50:91–99. CrossRefGoogle Scholar
  16. Choi K, Ng AHC, Fobel R et al (2013) Automated digital microfluidic platform for magnetic-particle-based immunoassays with optimization by design of experiments. Anal Chem 85:9638–9646. CrossRefGoogle Scholar
  17. Collins DJ, Alan T, Helmerson K, Neild A (2013) Surface acoustic waves for on-demand production of picoliter droplets and particle encapsulation. Lab Chip 13:3225–3231. CrossRefGoogle Scholar
  18. Cui W, Zhang M, Duan X et al (2015) Dynamics of electrowetting droplet motion in digital microfluidics systems: from dynamic saturation to device physics. Micromachines 6:778–789. CrossRefGoogle Scholar
  19. Darhuber AA, Valentino JP, Davis JM et al (2003) Microfluidic actuation by modulation of surface stresses. Appl Phys Lett 82:657–659. CrossRefGoogle Scholar
  20. Das D, Das S, Biswas K (2010) Effect of electrode geometry on voltage reduction in EWOD based devices. Int Conf Syst Med Biol ICSMB 2010 Proc. CrossRefGoogle Scholar
  21. Datta P, Dutta A, Majumder R et al (2016) A design of digital microfluidic biochip along with structural and behavioural features in triangular electrode based array. Proc Comput Sci 93:183–190. CrossRefGoogle Scholar
  22. Ding X, Li P, Lin SCS et al (2013) Surface acoustic wave microfluidics. Lab Chip 13:3626–3649. CrossRefGoogle Scholar
  23. Dittrich PS, Manz A (2005) Single-molecule fluorescence detection in microfluidic channels—the Holy Grail in μtAS? Anal Bioanal Chem 382:1771–1782. CrossRefGoogle Scholar
  24. Dixon C, Ng AHC, Fobel R et al (2016) An inkjet printed, roll-coated digital microfluidic device for inexpensive, miniaturized diagnostic assays. Lab Chip 16:4560–4568. CrossRefGoogle Scholar
  25. Eaker CB, Joshipura ID, Maxwell LR et al (2017) Electrowetting without external voltage using paint-on electrodes. Lab Chip 17:1069–1075. CrossRefGoogle Scholar
  26. Fan SK, Hsieh TH, Lin DY (2009) General digital microfluidic platform manipulating dielectric and conductive droplets by dielectrophoresis and electrowetting. Lab Chip 9:1236–1242. CrossRefGoogle Scholar
  27. Fan SK, Yang H, Hsu W (2011) Droplet-on-a-wristband: chip-to-chip digital microfluidic interfaces between replaceable and flexible electrowetting modules. Lab Chip 11:343–347. CrossRefGoogle Scholar
  28. Gong J, Kim CJ (2008) Direct-referencing two-dimensional-array digital microfluidics using multilayer printed circuit board. J Microelectromech Syst 17:257–264. CrossRefGoogle Scholar
  29. Grissom D, Curtis C, Windh S et al (2015) An open-source compiler and PCB synthesis tool for digital microfluidic biochips. Integr VLSI J 51:169–193. CrossRefGoogle Scholar
  30. Gronewold TMA (2007) Surface acoustic wave sensors in the bioanalytical field: recent trends and challenges. Anal Chim Acta 603:119–128. CrossRefGoogle Scholar
  31. Hadwen B, Broder GR, Morganti D et al (2012) Programmable large area digital microfluidic array with integrated droplet sensing for bioassays. Lab Chip 12:3305–3313. CrossRefGoogle Scholar
  32. Islam MA, Tong AY (2017) A numerical study of parallel-plate and open-plate droplet transport in electrowetting-on-dielectrode (EWOD). Numer Heat Transf Part A Appl 71:805–821. CrossRefGoogle Scholar
  33. Jain V, Devarasetty V, Patrikar R (2017a) Effect of electrode geometry on droplet velocity in open EWOD based device for digital microfluidics applications. J Electrostat 87:11–18. CrossRefGoogle Scholar
  34. Jain V, Devarasetty V, Patrikar R (2017b) Study of two-dimensional open EWOD system using printed circuit board technology. Glob J Res Eng Electr Electron Eng 17Google Scholar
  35. Jain V, Raj TP, Deshmukh R, Patrikar R (2017c) Design, fabrication and characterization of low cost printed circuit board based EWOD device for digital microfluidics applications. Microsyst Technol 23:389–397. CrossRefGoogle Scholar
  36. Khodayari M, Carballo J, Crane NB (2012) A material system for reliable low voltage anodic electrowetting. Mater Lett 69:96–99. CrossRefGoogle Scholar
  37. Kirby AE, Lafrenière NM, Seale B et al (2014) Analysis on the go: quantitation of drugs of abuse in dried urine with digital microfluidics and miniature mass spectrometry. Anal Chem 86:6121–6129. CrossRefGoogle Scholar
  38. Kondoh J (2018) Nonlinear acoustic phenomena caused by surface acoustic wave and its application to digital microfluidic system. Jpn J Appl Phys 57:1–8. CrossRefGoogle Scholar
  39. Kong T, Brien R, Njus Z et al (2016) Motorized actuation system to perform droplet operations on printed plastic sheets. Lab Chip 16:1861–1872. CrossRefGoogle Scholar
  40. Krupenkin TN, Taylor JA, Schneider TM, Yang S (2004) From rolling ball to complete wetting: the dynamic tuning of liquids on nanostructured surfaces. Langmuir 20:3824–3827. CrossRefGoogle Scholar
  41. Lee J, Choi YS, Lee Y et al (2012) Rapid and sensitive detection of cardiac markers in human serum using surface acoustic wave immunosensor. Mater Res Soc Symp Proc 1415:165–171. CrossRefGoogle Scholar
  42. Li YJ, Cahill BP (2017) Frequency dependence of low-voltage electrowetting investigated by impedance spectroscopy. Langmuir 33:13139–13147. CrossRefGoogle Scholar
  43. Li Y, Fu YQ, Brodie SD et al (2012) Integrated microfluidics system using surface acoustic wave and electrowetting on dielectrics technology. Biomicrofluidics 6:1–9. CrossRefGoogle Scholar
  44. Li Y, Li H, Baker RJ (2014) Volume and concentration identification by using an electrowetting on dielectric device. 2014 IEEE Dallas Circuits Syst Conf Enabl Internet Things From Sens Serv DCAS 2014. CrossRefGoogle Scholar
  45. Lienemann J, Greiner A, Korvink JG (2003) Electrode shapes for electrowetting arrays. 2003 Nanotechnol Conf Trade Show Nanotech 2003 1:94–97Google Scholar
  46. Liu Y, Liang YE, Sheng YJ, Tsao HK (2015) Ultralow voltage irreversible electrowetting dynamics of an aqueous drop on a stainless steel surface. Langmuir 31:3840–3846. CrossRefGoogle Scholar
  47. Lomax DJ, Kant P, Williams AT et al (2016) Ultra-low voltage electrowetting using graphite surfaces. Soft Matter 12:8798–8804. CrossRefGoogle Scholar
  48. Maglione MS, Casalini S, Georgakopoulos S et al (2018) Fluid mixing for low-power ‘digital microfluidics’ using electroactive molecular monolayers. Small 14:1–7. CrossRefGoogle Scholar
  49. Mcdonald JC, Duffy DC, Anderson JR, Chiu DT (2000) Fabrication of microfluidic systems in PDMS. Electrophoreses 21:27–40CrossRefGoogle Scholar
  50. Mibus M, Zangari G (2017) Performance and reliability of electrowetting-on-dielectric (EWOD) systems based on tantalum oxide. ACS Appl Mater Interfaces 9:42278–42286. CrossRefGoogle Scholar
  51. Mibus M, Hu X, Knospe C et al (2016) Failure modes during low-voltage electrowetting. ACS Appl Mater Interfaces 8:15767–15777. CrossRefGoogle Scholar
  52. Mijatovic D, Eijkel JCT, Van Den Berg A (2005) Technologies for nanofluidic systems: top-down vs. bottom-up—a review. Lab Chip 5:492–500. CrossRefGoogle Scholar
  53. Min X, Bao C, Kim WS (2019) Additively manufactured digital microfluidic platforms for ion-selective sensing. ACS Sens 4:918–923. CrossRefGoogle Scholar
  54. Monkkonen L, Edgar JS, Winters D et al (2016) Screen-printed digital microfluidics combined with surface acoustic wave nebulization for hydrogen-deuterium exchange measurements. J Chromatogr A 1439:161–166. CrossRefGoogle Scholar
  55. Moon H, Cho SK, Garrell RL, Kim CJ (2002) Low voltage electrowetting-on-dielectric. J Appl Phys 92:4080–4087. CrossRefGoogle Scholar
  56. Nahar MM, Nikapitiya JB, You SM, Moon H (2016) Droplet velocity in an electrowetting on dielectric digital microfluidic device. Micromachines 7:1–16. CrossRefGoogle Scholar
  57. Nampoothiri KN, Seshasayee MS, Srinivasan V et al (2018) Direct heating of aqueous droplets using high frequency voltage signals on an EWOD platform. Sens Actuators B Chem 273:862–872. CrossRefGoogle Scholar
  58. Nbelayim P, Sakamoto H, Kawamura G et al (2017) Preparation of thermally and chemically robust superhydrophobic coating from liquid phase deposition and low voltage reversible electrowetting. Thin Solid Films 636:273–282. CrossRefGoogle Scholar
  59. Ng JMK, Stroock AD, Whitesides GM (2002) Components for integrated poly(dimethylsiloxane) microfluidic systems. Electrophoresis 23:3461–3473CrossRefGoogle Scholar
  60. Nie J, Ren Z, Shao J et al (2018) Self-powered microfluidic transport system based on triboelectric nanogenerator and electrowetting technique. ACS Nano 12:1491–1499. CrossRefGoogle Scholar
  61. Palma C, Deegan RD (2018) Droplet translation actuated by photoelectrowetting. Langmuir 34:3177–3185. CrossRefGoogle Scholar
  62. Park JK, Lee SJ, Kang KH (2010a) Fast and reliable droplet transport on single-plate electrowetting on dielectrics using nonfloating switching method. Biomicrofluidics 4:1–8. CrossRefGoogle Scholar
  63. Park SY, Teitell MA, Chiou EPY (2010b) Single-sided continuous optoelectrowetting (SCOEW) for droplet manipulation with light patterns. Lab Chip 10:1655–1661. CrossRefGoogle Scholar
  64. Pei SN, Valley JK, Neale SL et al (2010) Light-actuated digital microfluidics for large-scale, parallel manipulation of arbitrarily sized droplets. In: 2010 IEEE 23rd international conference on micro electro mechanical systems (MEMS), pp 252–255Google Scholar
  65. Peng C, Zhang Z, Kim CJ, Ju YS (2014) EWOD (electrowetting on dielectric) digital microfluidics powered by finger actuation. Lab Chip 14:1117–1122. CrossRefGoogle Scholar
  66. Pohl A (2000) A review of wireless SAW sensors. IEEE Trans Ultras Ferroelectr Freq Control 47:317–332CrossRefGoogle Scholar
  67. Pollack MG, Fair RB, Shenderov AD (2000) Electrowetting-based actuation of liquid droplets for microfluidic applications. Appl Phys Lett 77:1725–1726. CrossRefGoogle Scholar
  68. Pooyan S, Passandideh-Fard M (2018) Investigation of the effect of geometric parameters on EWOD actuation in rectangular microchannels. J Fluids Eng 140:091104. CrossRefGoogle Scholar
  69. Qi L, Niu Y, Ruck C, Zhao Y (2019) Mechanical-activated digital microfluidics with gradient surface wettability. Lab Chip 19:223–232. CrossRefGoogle Scholar
  70. Ribet F, De Pietro L, Roxhed N, Stemme G (2018) Gas diffusion and evaporation control using EWOD actuation of ionic liquid microdroplets for gas sensing applications. Sens Actuators B Chem 267:647–654. CrossRefGoogle Scholar
  71. Rudan M (2015) Physics of semiconductor devices. Phys Semicond Devices. CrossRefGoogle Scholar
  72. Ruecha N, Lee J, Chae H et al (2017) Paper-Based digital microfluidic chip for multiple electrochemical assay operated by a wireless portable control system. Adv Mater Technol 2:1600267. CrossRefGoogle Scholar
  73. Samad MF, Kouzani AZ, Rahman MM et al (2015) Design and fabrication of an electrode for low-actuation-voltage electrowetting-on-dielectric devices. Procedia Technol 20:20–25. CrossRefGoogle Scholar
  74. Samad MF, Kouzani AZ, Hossain MF et al (2017) Reducing electrowetting-on-dielectric actuation voltage using a novel electrode shape and a multi-layer dielectric coating. Microsyst Technol 23:3005–3013. CrossRefGoogle Scholar
  75. Shirinkami H, Kim J, Lee C et al (2017) Improvement of droplet speed and stability in electrowetting on dielectric devices by surface polishing. Biochip J 11:316–321. CrossRefGoogle Scholar
  76. Sohail S, Mistri EA, Khan A et al (2016) Fabrication and performance study of BST/Teflon nanocomposite thin film for low voltage electrowetting devices. Sens Actuators A Phys 238:122–132. CrossRefGoogle Scholar
  77. Tan X, Zhou Z, Cheng MMC (2012) Electrowetting on dielectric experiments using graphene. Nanotechnology. CrossRefGoogle Scholar
  78. Tang X, Wang L (2018) Loss-free photo-manipulation of droplets by pyroelectro-trapping on superhydrophobic surfaces. ACS Nano 12:8994–9004. CrossRefGoogle Scholar
  79. Tröls A, Clara S, Jakoby B (2016) Sensors and actuators A: physical A low-cost viscosity sensor based on electrowetting on dielectrics. Sens Actuators A Phys 244:261–269. CrossRefGoogle Scholar
  80. Trung-Dung L, Nam-Trung N (2010) Surface acoustic wave driven microfluidics—a review. Micro Nanosyst 1:1–9Google Scholar
  81. Wainright A, Nguyen UT, Bjornson TL, Boone TD (2003) Preconcentration and separation of double-stranded DNA fragments by electrophoresis in plastic microfluidic devices. Electrophoresis 24:3784–3792. CrossRefGoogle Scholar
  82. Wang W, Jones TB (2015) Moving droplets between closed and open microfluidic systems. Lab Chip 15:2201–2212. CrossRefGoogle Scholar
  83. Wang L, Duan J, Zhang B, Wang W (2016) Polydimethylsiloxane as dielectric and hydrophobic material in electro-wetting liquid lens. 8th Int Symp Adv Opt Manuf Test Technol Des Manuf Test Micro-Nano-Optical Devices Syst Smart Struct Mater. CrossRefGoogle Scholar
  84. Wang H, Chen L, Sun L (2017a) Digital microfluidics: a promising technique for biochemical applications. Front Mech Eng 12:1–16. CrossRefGoogle Scholar
  85. Wang J, Hu J, Sun Q et al (2017b) Dielectric and energy storage performances of PVDF-based composites with colossal permittivitied Nd-doped BaTiO3 nanoparticles as the filler. AIP Adv. CrossRefGoogle Scholar
  86. Whitesides GM (2006) The origins and the future of microfluidics. Nature 442:368–373. CrossRefGoogle Scholar
  87. Yafia M, Najjaran H (2013) High precision control of gap height for enhancing principal digital microfluidics operations. Sens Actuators B Chem 186:343–352. CrossRefGoogle Scholar
  88. Yafia M, Ahmadi A, Hoorfar M, Najjaran H (2015a) Ultra-portable smartphone controlled integrated digital microfluidic system in a 3D-printed modular assembly. Micromachines 6:1289–1305. CrossRefGoogle Scholar
  89. Yafia M, Shukla S, Najjaran H (2015b) Fabrication of digital microfluidic devices on flexible paper-based and rigid substrates via screen printing. J Micromech Microeng. CrossRefGoogle Scholar
  90. Yang C, Zhang Z, Li G (2018) Programmable droplet manipulation by combining a superhydrophobic magnetic film and an electromagnetic pillar array. Sens Actuators B Chem 262:892–901. CrossRefGoogle Scholar
  91. Yeo LY, Friend JR (2009) Ultrafast microfluidics using surface acoustic waves. Biomicrofluidics 3:1–23. CrossRefGoogle Scholar
  92. Young PM, Mohseni K (2008) Calculation of DEP and EWOD forces for application in digital microfluidics. J Fluids Eng 130:081603. CrossRefGoogle Scholar
  93. Yu P-H, Lai KY-T, Li Z et al (2017) Droplet size-aware high-level synthesis for micro-electrode-dot-array digital microfluidic biochips. IEEE Trans Biomed Circ Syst 11:612–626. CrossRefGoogle Scholar
  94. Zhang Y, Nguyen NT (2017) Magnetic digital microfluidics—a review. Lab Chip 17:994–1008. CrossRefGoogle Scholar
  95. Zhang Y, Park S, Liu K et al (2011) A surface topography assisted droplet manipulation platform for biomarker detection and pathogen identification. Lab Chip 11:398–406. CrossRefGoogle Scholar
  96. Zhang SP, Lata J, Chen C et al (2018) Digital acoustofluidics enables contactless and programmable liquid handling. Nat Commun 9:1–11. CrossRefGoogle Scholar

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© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Additive Manufacturing Laboratory, School of Mechatronic Systems EngineeringSimon Fraser UniversitySurreyCanada

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