title: A microfluidic chip for direct and rapid trapping of white blood cells from whole blood.
abstract: Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are an important target of analysis. We proposed an integrated microfluidic chip for direct and rapid trapping WBCs from whole blood. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped by the arrays of trapping structures. We fabricated the PDMS (polydimethylsiloxane) chip using soft lithography and determined the critical flow velocities of tartrazine and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. The time taken for complete lysis of whole blood was about 85 s under the flow velocity 0.05 μl/min. The RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures. The chip trapped about 2.0 × 10(3) from 3.3 × 10(3) WBCs.
authors.affiliation: Science and Technology on Micro/Nano Fabrication Laboratory, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Chen
authors.affiliation: Science and Technology on Micro/Nano Fabrication Laboratory, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Di
authors.initials: D
authors.lastname: Chen
authors.affiliation: Science and Technology on Micro/Nano Fabrication Laboratory, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yuan
authors.affiliation: Science and Technology on Micro/Nano Fabrication Laboratory, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Key Laboratory of Thin Film and Microfabrication Technology of Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen