Microfluidic diagnostic devices often require handling particles or cells with different sizes. In thisinvestigation, a tunable hydrophoretic device was developed which consists of a polydimethylsiloxane(PDMS) slab with hydrophoretic channel, a PDMS diaphragm with pressure channel, and a glass slide. Theheight of the hydrophoretic channel can be tuned simply and reliably by deforming the elastomeric diaphragmwith pressure applied on the pressure channel. This operation allows the device to have a large operating rangewhere different particles and complex biological samples can be processed. The focusing performance of thisdevice was tested using blood cells that varied in shape and size. The hydrophoretic channel had a large crosssection which enabled a throughput capability for cell focusing of ~15 000 cells s-1, which was more than theconventional hydrophoretic focusing and dielectrophoresis (DEP)-active hydrophoretic methods. Thistunable hydrophoretic focuser can potentially be integrated into advanced lab-on-a-chip bioanalysis devices.
Yan, Sheng, Jun Zhang, Huaying Chen, Gursel Alici, Haiping Du, Yonggang Zhu, Weihua Li