With the success of the project “Programmable droplet”, a new era has begun to the field of microfluidics. Microfluidics is an interdisciplinary branch that deals with the behavior, precise control and manipulation of fluids whose sizes are geometrically constrained to small scale. This branch has vast practical applications, especially in molecular biology. Microfluidics has led to the creation of powerful tools for biologists to control the complete cellular environment leading to new discoveries. In spite of having great importance in many areas, microfluidics is spectacled to follow those old techniques where biological solutions are pumped through microscopic channels connected by mechanical valves.
Recently a research group from MIT Media Lab led by Udayan Umapathy MIT have developed a new hardware technique with higher efficiency and lower costs. Those hardware use electric fields to move droplets of chemical or biological solutions around the surface of the device to carry out biological experiments. The system includes software that allows users to describe the experiment they want to conduct at a higher level of generality. The software then automatically calculates the path of the droplets across the surface and coordinate the timing of the operation.
The new design has a printed circuit board, a commodity electronic device that consists of a plastic board with copper wire deposited on the top of it. The circuit board is coated with a dense array of tiny spheres made from the hydrophobic material. This prevents the molecules from sticking to the surface and reduces the risk of contamination. Due to this hydrophobic coating the droplets when deposit above the surface tries to acquire spherical shape. When the electrode below the droplet is charged, the droplet flattened out. If the electrode is gradually turned off while that next to it is gradually turned on the hydrophobic material drive the droplet towards the charged electrode. In this way, the droplets move on the surface.
This new technique can be used to test thousands of reactions in parallel. Umapathy and his coworkers believe this digital microfluidics could drastically cut the cost of experiments in industrial biology.