Mengyan Li

Date of Award

Summer 2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Engineering

First Advisor

Michael J. McShane

Abstract

This dissertation elaborates the design and fabrication of in vitro cell culture scaffolds using microfabrication and electrostatic layer-by-layer self-assembly (LbL) technologies, and develops the so-called layer-by-layer lift-off (LbL-LO) technique to control surface topography, surface properties, and underlying architectures of the scaffolds. Smooth muscle cells were cultured on the fabricated scaffolds with gelatin, fibronectin, and polyelectrolytes (PSS, PDDA, PAH, and PEI) as surface materials, multilayer polyelectrolytes as architectures, deposited in strip- and square-patterns. It was found that the exposed surface materials, which have different charge, hydrophobicity, and chemical structure (e.g., amino acid sequence), affect the adhesion of smooth muscle cells. Cells attached and grew on negatively-charged gelatin, PSS, and acid-treated glass surfaces rather than on positively-charged PDDA and PAH surfaces. The cell-adhesive proteins gelatin and fibronectin improve the attachment and further growth of smooth muscle cells, and cells attached to these surfaces showed more natural morphology than on PSS-coated surfaces. In addition, the underlying architectures of the polyelectrolyte thin films also significantly influence the cell morphologies and attachment. Cells on thicker nanofilms (20-bilayer) showed more elongated and spread-out morphology than on the thinner ones (e.g., 2-bilayer). Cells cultured on the gelatin- and fibronectin-coated strip patterns showed aligned patterns along the main axis of the strips. It was observed cells on 60μm wide strips had better alignment than on the 120μm strips. The experimental results indicate that the LbL-LO technique is an efficient method to fabricate in vitro cell culture scaffolds with precise control of the surface properties and topography in three dimensions, and therefore, to study the cell behavior. The results of study suggest that a combination of micro/nanotechnologies for biosurface engineering has great potential in the application of tissue engineering and other related areas.

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