Digital microfluidic theory and improvements

“Digital microfluidics” is a term used to describe the fluid-handling technique in which discrete liquid droplets are manipulated electromechanically across an array of electrodes coated with a hydrophobic insulator. For new users, we recently developed an open-source digital microfluidic control system, called DropBot (see the DropBot archive for schematics, downloads, instructions, and more). We have written several review articles describing digital microfluidics (see articles in Science, ABC, Adv. Mat., COCB, or ARAC), and have worked to develop a variety of method improvements, tackling issues including biofouling, device geometry limitations, electronic control systems, and reliable dispensing. Papers describing our efforts in these areas are listed below.

Swyer, I.; Fobel, R.; Wheeler, A.R. "Velocity Saturation in Digital Microfluidics" Langmuir 2019, 35, 5342-5352. Supplementary: Info, Movie 1, Movie 2, Movie 3.

Dixon, C.; Ng, A.H.C.; Fobel, R.; Miltenburg, M.B.; Wheeler, A.R. "An Inkjet Printed, Roll-Coated Digital Microfluidic Device for Inexpensive, Miniaturized Diagnostic Assays" Lab on a Chip, 2016, 16, 4560-4568. Supporting info. Supporting video.

Sarvothaman, M.K.; Kim, K.S.; Seale, B.; Brodersen, P.M.; Walker, G.C.; Wheeler, A.R. "Dynamic Fluoroalkyl Polyethylene Glycol Co-Polymers: A New Strategy for Reducing Protein Adhesion in Lab-on-a-Chip Devices" Adv. Func. Mater., 2015, 25, 506-515. Supporting info.

Fobel, R.; Kirby, A.E.; Ng, A.H.C.; Farnood, R.R.; Wheeler, A.R. "Paper Microfluidics Goes Digital" Adv. Mat. 2014, 26, 2838-2843. Supporting info.

Fobel, R.; Fobel, C.; Wheeler, A.R. "Dropbot: An Open-Source Digital Microfluidic Control System with Precise Control of Electrostatic Driving Force and Instantaneous Drop Velocity MeasurementAppl. Phys. Lett. 2013, 102, 193513. Supporting info.

Eydelnant, I.A.; Uddayasankar, U.; Li, B.; Liao, M.W.; Wheeler, A.R. "Virtual Microwells for Digital Microfluidic Reagent Dispensing and Cell Culture" Lab on a Chip 2012, 12, 750-757.

Au, S.H.; Kumar, P.; Wheeler, A.R. "A New Angle on Pluronic Additives: Advancing Droplets and Understanding in Digital MicrofluidicsLangmuir 2011, 27, 8586-8594. Suppl. File 1.

Shih, S.C.C.; Fobel, R.; Kumar, P.; Wheeler, A.R. "A Feedback Control System for High-Fidelity Digital MicrofluidicsLab Chip, 2011, 11, 535-540. Suppl. File 1Suppl. File 2.

Abdelgawad, M., Park, P.; Wheeler, A.R. "Optimization of Device Geometry in Single-Plate Digital MicrofluidicsJ. App. Phys. 2009, 105, 094506.

Yang, H.; Luk, V.N.; Abdelgawad, M.; Barbulovic-Nad, I.; Wheeler, A.R. "A World-to-Chip Interface for Digital MicrofluidicsAnal. Chem., 2009, 81, 1061-1067.

Luk, V.N.; Mo, G.C.; Wheeler, A.R. "Pluronic Additives: A Solution to Sticky Problems in Digital MicrofluidicsLangmuir 2008, 24, 6382-6389. Supporting Info

Abdelgawad M.; Freire S.; Yang H.; Wheeler A. R. "All-Terrain Droplet ActuationLab Chip 2008, 8, 672-677.  Supporting Info