Examination Committee

Prof Zhiyong FAN, ECE/HKUST (Chairperson)
Prof Levent YOBAS, ECE/HKUST (Thesis Supervisor)
Prof Ming LIU, ECE/HKUST

Abstract

Cell poration and intracellular delivery are significant in the therapeutic and biochemistry research fields. Current existing technologies suffer from high cost or low cell viability problems and usually rely on virus vectors, transfection reagents or electrical fields. In this thesis, a microfluidic method is introduced for cell mechanoporation and cytosolic delivery. The mechanical delivery waives the requirement of reagents and electrical field and has good performance in delivery of different materials to different types of cells. 

The cell mechanoporation and cytosolic delivery are performed in a silicon based microfluidic device. The device contains point microconstrictions featuring sharp edges which are formed by silicon isotropic etching. The constriction size is smaller than the cell diameter. Cell suspensions driven by the regulator-controlled pressure are injected into the device. Suspended cells deform to pass through the constriction, leading to the membrane poration. Cell suspension contains the material of interest, which can enter into the cell cytosol when the membrane pores are generated. We used numerical modeling to study the flow in the channel and the cell deformation in the constrictions. The cells in the constrictions experience high stress and strain rate, suggesting a high possibility of poration. We delivered dextran molecules, anti-tubulin antibodies and siRNA molecules to different types of cells. The delivery performance is evaluated by microscopic and flow cytometer analyses. The cytosolic delivery has good efficiency across materials and cell types. And the cell viability after delivery maintains in high level.