Microfluidics – Controlling the Fluids


Can we control fluids even if we can’t see them? By now, most of us are used to having tiny electronic components on nano scale invisible even to a microscope, but is there something similar in the world of fluidics?

 

Fluid dynamics is a well known scientific discipline, that has been thoroughly studied for centuries. But what happens if parts of the fluidic system grow smaller and smaller, until a human eye can’t see them anymore, to the size of a single biological cell? When confined to such small spaces, fluids exhibit new, unexpected behaviors. Forces such as viscous and Van der Waals forces, that have virtually no effect on macro scale, are now taking over. That calls for a new discipline that can explain and apply these effects to serve us best – microfluidics.

 

Microfluidics is a young and exciting discipline of engineering, that allows us to manipulate fluids on micro and nano scale, enabling medicine, biology, and chemistry to go places no one ever dreamed of. Imagine for instance a solution of 1 million cells that needs to be analyzed to detect anomalies or diseases. To do this manually is time consuming, difficult, and not very precise. Microfluidics allows us to perform such analyses very quickly and precisely, analyzing cells one by one.

 

Researchers at BioSense, working on improving food quality, developed a technique for aligning cells into a single-cell array ready for analysis using an effect that liquids exhibit in strong electrostatic fields, known as the Taylor cone effect. A conical fluidic structure is formed instead of a spherical drop when electrostatic force equals the surface tension on the surface of the liquid drop, allowing the formation of a tiny jet with the diameter of several microns at the tip of the cone. When we apply this technique to a solution of cells, raw milk for example, we can align cells in a single-cell array and analyze them automatically one by one.