Continuous-flow optoelectrofluidic focusing and concentration of nanoparticles

Abstract

Nanoparticle concentration techniques have a strong influence on biomedical and clinical applications. Single cell analysis techniques have a strong influence on biomedical and clinical applications. Pre-concentration of the sample is the main factor for application performance. General nanoparticle concentration techniques such as centrifugation and lyophilization have some limitations, such as aggregation or sample damage, and are therefore not suitable to control the small amount of sample for biological application. On the other hand, optoelectrofluidic technology showed the possibility to focus nanoparticles in a static condition by AC electroosmosis, but all observations were performed using image analysis and thus sample acquirement was not possible. In this thesis, a continuous-flow optoelectrofluidic chip was introduced. Optoelectrofluidic focusing effect in the continuous-flow device was investigated under various conditions, including voltage, flow rate, frequency, particle size, and electrode shape. Three-outlet channel for collecting the concentrated sample was also designed and fabricated. The device was demonstrated with polystyrene nanoparticles and the concentrated sample was successfully acquired and analyzed by dynamic light scattering. These phenomena can be utilized as a novel method for concentrating biological samples in the nanometer range.