DropBot is an open-source Digital Microfluidic (DMF) automation system developed in the Wheeler Lab. It can be used to manipulate discrete droplets on the surface of an array of electrodes coated with a hydrophobic insulator. DMF has many applications in the fields of biology and chemistry, including diagnostics, cell-based assays, and chemical synthesis. The DropBot features a modular and extensible design, an intuitive user interface, and is capable of driving up to 120 independent channels. It also provides dynamic impedance sensing which enables closed-loop control and real-time measurement of:

drop position
instantaneous drop velocity
electrostatic driving force

Check out the Wheeler Lab’s recent entry in NSERC’s Science Action video competition.

System overview

DropBot is built around an Arduino-based instrument and is controlled by a custom software interface called Microdrop. Users can activate/deactivate electrodes on the DMF device by clicking their mouse on the webcam video overlay, providing an intuitive interface with real-time visual feedback. Sequences of actuation steps can be pre-programmed and run automatically, enabling fully automated operation. The system is designed as a loosely-coupled set of modules, which means that it is relatively easy to extend the hardware and/or software capabilities.

Open-source

All components are open-source, subject to the GPL (software code) or Creative Commons Attribution-ShareAlike licence (hardware designs), meaning you are free to make your own.

Get involved

For more information or to request community DropBot support, please join the forum. For announcements concerning future releases/updates, sign up for the DropBot announce mailing list.

Videos

Real-time control and velocity measurements

Demonstration of real-time drop control and protocol programming. This video also highlights the systems ability to measure drop velocity from electrical impedance.

Automated protocol with video overlay

Video showing an automated protocol with drop dispensing, merging, mixing and splitting.

Software

Microdrop software

Microdrop is the graphical user interface for the DropBot DMF automation system.

Control board software

The control board software consists of Arduino firmware, a Python module for communicating over a serial connection, and a plugin for the Microdrop application.

Hardware

All hardware designs can be viewed or edited using KiCAD or Sketchup.

Control board

Signal generator board

High-voltage switching board

Pogo pin connector board

Device connector

DropBot case

DropBots in the wild

Here’s a map of all of the known DropBot systems out there (both up and running and those being built). If you are building a system, add a wiki page or link to another webpage/blog here to document your progress. Email ryan[dot]fobel[at]utoronto[dot]ca if you want to add a pin to the map.