| Living cells are endowed with an exquisite repertoire of functions, including the machinery to synthesize complex molecules, to detect extracellular analytes, and to interact with other cells. The nascent field of engineered cell adhesion has captured the imaginations of researchers hoping to construct new types of synthetic devices that contain living cells. Such devices might one day find use in applications including biosensing, drug discovery, artificial tissue engineering, and basic studies in cell biology. While pioneering studies have established the premise of engineering cell adhesion to surfaces, tools for the construction of complex cell-based devices have been lacking. The demands placed on these tools will be significant, as they must allow the incorporation of many different kinds of cells into complex, multi-component devices without perturbing cellular physiology.In this work, I focus on the development of a new tool that can be used to "program" cellular adhesion using strands of DNA. Chapter 2 focuses on the experimental validation of this concept. Specifically, cells coated with single-stranded DNA were shown to bind to complementary DNA on surfaces in a sequence-specific manner. Initial work with both naturally adherent and non-adherent cells suggested that the linkage strategy was compatible with a number of experimental platforms, and could establish patterns of cells for long-term culture.Chapter 3 describes the adaptation of this strategy into a highly-efficient system for cell patterning, capable of achieving single-cell resolution. Detailed biophysical characterization of the system was conducted. This system was also used to prepare microarrays of cells (Chapter 4). Arrays comprising multiple cell types were assembled and cultured for extended periods. On-chip assay work established that bound cells retained similar physiological properties to those of unbound cells, and these experiments identified methods for using cellular microarrays in sensing and screening applications.Finally, Chapter 5 describes future directions for this technology in the context of initial work already completed. Progress towards the construction of an integrated, cellbased analytical microdevice is described. Also discussed is progress toward the utilization of this technology in several new platforms, including supported lipid bilayers, three-dimensional cellular assemblies, and atomic force microscopy studies. |
