Design, fabrication and characterization of low cost printed circuit board based EWOD device for digital microfluidics applications

Digital microfluidics (DMF) is an emerging liquid-handling technology that enables individual control over droplets on array of electrodes. In this paper a low cost approach for development and characterization of open configured electro wetting on dielectric (EWOD) based digital microfluidic device is presented. The array of electrodes pattern with 155 μm gap is realized on copper plated printed circuit board (PCB). Biocompatible polydimethylsiloxane (PDMS) is used as dielectric as well as hydrophobic layer which is a competitive substitute of expensive materials like Teflon-AF and parylene-C. The device is tested by the in-house developed low cost droplet handling and characterization system. A contact angle is measured by curve fitting; the volume of a droplet is calculated using a novel approach based on mathematical modeling of droplet as a spherical cap. The droplet transporting and merging are successfully performed on a fabricated device and velocities for forward and reverse direction on square and interdigitated pattern are analyzed. The device is also successfully demonstrated for the mixing applications using direct statistical method.

[1]  Wyatt C. Nelson,et al.  Droplet Actuation by Electrowetting-on-Dielectric (EWOD): A Review , 2012 .

[2]  S. Cho,et al.  Creating, transporting, cutting, and merging liquid droplets by electrowetting-based actuation for digital microfluidic circuits , 2003 .

[3]  Richard B. Fair,et al.  Integrated chemical/biochemical sample collection, pre-concentration, and analysis on a digital microfluidic lab-on-a-chip platform , 2004, SPIE Optics East.

[4]  Phil Paik,et al.  Electrowetting-based droplet mixers for microfluidic systems. , 2003, Lab on a chip.

[5]  R. Fair,et al.  A scaling model for electrowetting-on-dielectric microfluidic actuators , 2009 .

[6]  Hong Liu,et al.  Dielectric materials for electrowetting-on-dielectric actuation , 2009 .

[7]  A. Wheeler,et al.  The Digital Revolution: A New Paradigm for Microfluidics , 2009 .

[8]  C. Kim,et al.  Direct-Referencing Two-Dimensional-Array Digital Microfluidics Using Multilayer Printed Circuit Board , 2008, Journal of Microelectromechanical Systems.

[9]  K. Mohseni,et al.  A Unified Velocity Model for Digital Microfluidics , 2007 .

[10]  Aaron R. Wheeler,et al.  Low-cost, rapid-prototyping of digital microfluidics devices , 2008 .

[11]  R. Fair,et al.  CLINICAL DIAGNOSTICS ON HUMAN WHOLE BLOOD, PLASMA, SERUM, URINE, SALIVA, SWEAT, AND TEARS ON A DIGITAL MICROFLUIDIC PLATFORM , 2003 .

[12]  Albert Folch,et al.  Microvalves and Micropumps for BioMEMS , 2011, Micromachines.

[13]  A. Mata,et al.  Characterization of Polydimethylsiloxane (PDMS) Properties for Biomedical Micro/Nanosystems , 2005, Biomedical microdevices.

[14]  R. Fair,et al.  A digital microfluidic biosensor for multianalyte detection , 2003, The Sixteenth Annual International Conference on Micro Electro Mechanical Systems, 2003. MEMS-03 Kyoto. IEEE.

[15]  John Ralston,et al.  Contact angle saturation in electrowetting. , 2005, The journal of physical chemistry. B.

[16]  C. Kim,et al.  Electrowetting and electrowetting-on-dielectric for microscale liquid handling , 2002 .

[17]  Nam-Trung Nguyen,et al.  Micromixers: Fundamentals, Design, and Fabrication , 2008 .

[18]  R. Fair,et al.  Droplet-based microfluidic lab-on-a-chip for glucose detection , 2004 .

[19]  J. Baret,et al.  Electrowetting: from basics to applications , 2005 .

[20]  R. Fair,et al.  Electrowetting-based actuation of droplets for integrated microfluidics. , 2002, Lab on a chip.

[21]  Riccardo Scipinotti,et al.  Polydimethylsiloxane material as hydrophobic and insulating layer in electrowetting-on-dielectric systems , 2014, Microelectron. J..