Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Electrical and Computer Engineering

Supervisor

Dr. Silvia Mittler

Abstract

In this thesis, Waveguide Evanescent Field Scattering (WEFS) microscopy is developed as a non-invasive, label-free live cell imaging technique. This new high-contrast imaging can be employed to study the first hundred nanometers from the surface as it utilizes the evanescent field of a waveguide as the illumination source. Previously, waveguide evanescent field fluorescence (WEFF) microscopy was developed as a fluorescence imaging technique comparable to the total internal reflection fluorescent (TIRF) microscopy. Both the WEFF and WEFS technique utilizes the same fundamental concepts except in WEFS microscopy imaging is accomplished without the application of any fluorescent labeling. In this work, bacterial biofilms and osteoblasts were cultured on waveguides and imaged with WEFS microscopy. It was possible to detect cell-substrate interactions as well as imaging of cell membrane and cytoplasmic granularity with this microscopy. This non-invasive microscopy can have wide applications for real time imaging of live/dead cells with enhanced sensitivity and contrast.

One of the major investigations in tissue engineering is the fabrication of biomaterials that can serve as cell responsive scaffolds. In the present work, collagen thin films were fabricated on hydrophobic glass substrates employing Langmuir-Blodgett (LB) technology. Different orientation distributions of collagen fibrils were found using various geometrical shaped hydrophobic glass substrates. It was observed that the substrate geometry plays a significant role for the collagen orientation distribution. The different orientations of the collagen on the thin films were found to be dependent on the direction of dipping, flow parameters on the LB trough and size and shape of the substrates. The collagen films were also found to be stable under different temperature and solvent conditions for up to three months. The oriented collagen films need to be tested in the future for their application as waveguide coatings for WEFF and WEFS microscopy.