Real-time feedback control for engineered nanoelectrokinetic preconcentrator*

Nanoelectrokinetic preconcentration using ion concentration polarization (ICP) phenomenon is a highly effective method for simultaneously separating and concentrating biomolecules. Hence, this approach has been widely adopted in diagnostic applications, in which the presence of low abundant target is detected in a microfluidic channel.

However, typical ICP preconcentration systems had limitations for commercialization, as a skilled professional, tedious preliminary experiments and thorough analysis were required before the actual operation. Especially, their nuisances such as unceasing movements of the preconcentrated plug obstructed programmed decision for separation.

Therefore, we propose a real-time feedback control method to adjust the behavior and location of the plug in desired manners, by changing the external electrokinetic parameters properly.

The proposed system is composed of an optical unit that monitors the fluorescent plug and an electrical source with real-time feedback algorithm to apply amendable electric field.

Using this feedback control, one can develop and hold the preconcentrated plug at a desired location and automatically judge whether the targets are successfully separated or not. Thus, it significantly lowers entry barriers of using ICP concentrator.