Realization of microfluidic devices with steel displacement amplifiers for cell culturing and analysis

In this thesis, microfluidic devices with simple trapping mechanism which can be actuated by applying force to use them for cell culturing and analysis applications are designed, analyzed and fabricated. Steel displacement amplifiers are designed, analytically evaluated and simulated to use them as trapping mechanism in microfluidic channels. In addition, analytical model of the hydrodynamic resistance of device and the results of the flow simulations are discussed in order to describe and characterize the device. 50 μm-thick steel thin films, 1 mm-thick Poly methyl methacrylate (PMMA) plates, and 125 μm-thick Polyethylene naphthalate (PEN) films are used to realize the device. Fabrication methods, which are photolitography, electrochemical etching, wet etching, hot embossing, thermo-compression bonding and laser micromachining are illustrated. Electrochemical etching process is characterized. Results of displacement measurements of the steel displacement amplifier under different loads is presented . Coefficient of thermal expansion (CTE) difference problem that is encountered during hot embossing process of steel and PMMA is discussed. It is shown that using PEN substrates which have almost same CTE as the steel thin films solve the CTE mismatch issue. In conclusion, the final version of the fabricated device is presented. Moreover, necessary studies in order to actuate steel displacement amplifier embedded in microfluidic channel are discussed as a future work.