Microfluidic systems for high-throughput single-cell assays

Open Access
Santillo, Michael
Graduate Program:
Doctor of Philosophy
Document Type:
Date of Defense:
June 17, 2009
Committee Members:
  • Andrew Ewing, Dissertation Advisor
  • Andrew Ewing, Committee Chair
  • Philip C. Bevilacqua, Committee Member
  • Thomas E Mallouk, Committee Member
  • Andrew Zydney, Committee Member
  • Microfluidics
  • lab-on-a-chip
  • confocal
  • fluorescence
  • cell assay
  • bioanalytical chemistry
  • computational fluid dynamics
  • CFD
  • PDMS
Microfluidic devices have recently emerged as useful tools for performing biological and cellular assays. Compared to conventional assays, microfluidic technology has several advantages including the consumption of small sample volumes and ability to integrate multiple steps of an analysis into a single system. Furthermore, microfluidic systems can be automated and perform assays in a high-throughput fashion, resulting in faster analysis times and collection of data on the single cell level. In this dissertation applications of microfluidic systems for performing cell-based assays are demonstrated. In the second chapter, a device for monitoring changes in intercellular connectivity in an in vitro neuronal network was fabricated and the fluid flow characterized via confocal microscopy, simulations, and amperometry. This system exploits laminar flow and hydrodynamic focusing, allowing individual cells in specific locations to be addressed with pharmacological agents while imaging is performed on the cells in the network. Lysis of a non-pathogenic amoeba, Arcella vulgaris, was monitored on a microfluidic platform and described in the third chapter. This device allows multiple cells to be observed simultaneously after exposure to constant, controlled flow of chemical biocides. The data obtained shows that single cell lysis events are much different from an average value obtained from a cell population, and the efficacy of several detergents and biocides was compared. In the fourth chapter, computational fluid dynamics simulations were used to develop amperometric detection schemes for microchip electrophoresis. A novel technique for fabricating microfluidic devices was explored in the fifth chapter in which tape was used as a master mold to fabricate two PDMS micromixers. The fabrication scheme is easy to perform and allows microfluidic technology to be adapted without the use of cleanrooms and photolithography. In the sixth chapter, a microfluidic system for high-throughput exposure of PC12 cells was used to quantify reactive oxygen species in response to neurotoxins. The device contains a passive mixer and an array of cell traps that isolate cells and simplify multiplexed fluorescence imaging.