Advanced Liquid Logic’s digital microfluidic technology is based on the use of “electrowetting” to precisely manipulate droplets on a surface. Electrowetting describes the ability of an applied voltage to modulate the “wettability” of a surface. Aqueous droplets naturally “bead-up” on a hydrophobic surface but a voltage applied between a droplet and an insulated electrode can cause the droplet to spread on the surface as illustrated below.
Digital microfluidics harnesses the electrowetting effect to precisely manipulate droplets within a sealed microfluidic cartridge (also called a “Lab-on-a-chip”). Electrical signals are applied to an array of electrodes to control the size and position of each droplet. Droplets are transferred between adjacent electrodes by removing voltage from one electrode and applying it to the next one. The same processes can be used to dispense, merge or split droplets using electrical signals. Fully-programmable fluid handling is thereby achieved without the use of any pumps, valves or channels. The schematic cross-section below illustrates the structure of a digital microfluidic cartridge.
Advanced Liquid Logic has developed methods for implementing many bioassay protocols using digital microfluidics. Examples include:
- Quantitative analysis of DNA (qPCR) and RNA (RT-qPCR)
- Protein analysis using both enzymatic and immunoassay techniques
- DNA sequencing using a sequencing-by-synthesis method
- Sample preparation from many different sample matrices (blood, swabs, saliva, etc.)
- Preparation of fragment libraries for next generation sequencing