| Popis: |
Non-invasive and reliable communication with electrogenic cells is comprised of several techniques from dierent elds of research. Cellular signals need to be sensed and recorded utilizing extracellular recording devices with a temporal resolution that is higher than the duration of a single action potential (AP). Furthermore, the cells need to be situated in close proximity to the device and grow with a level of complexity that is low enough to follow connectivity and understand behavior, but is still complex enough to show plasticity and maturation. Finally, communication must be bi-directional, such that a dened, precise, and non-invasive input, can be combined with the interfacing setup. In this thesis, all the above mentioned challenges of cell transistor coupling were faced. A new recording device was built based on diamond substrates. The feasibility of diamond for electronic devices used in cell transistor coupling was demonstrated by recording from HL-1 cells. The ability to interface single cells was shown by recording from HEK cells that were synchronously patch-clamped. In addition, the generation of dened neural networks was tackled, and patterned, low density neural networks were generated on chip via aligned micro-contact printing. In order to improve the durability of the pattern generated, a covalent coupling chemistry for binding cell adhesion molecules was developed. Epoxy silane enabled one step coupling of biomolecules to the surface, providing cell repellent background in uncovered epoxysilane areas. Employing small peptides with cell adhesion properties minimized the cell adhesion layer. Thus, the cells should grow closer to the surface and the recording properties should be improved. Finally, next to recording from cells, the combination of a dened input into cellular networks with multisite recording was part of the research performed during this thesis. HL-1 cells were genetically engineered to express channelopsin. In combination with retinal, the light triggered cation permeable channelrhodopsin forms. A setup for dened stimulation of single spots was built. The cells were successfully depolarized using light and subsequently action potentials were evoked. Furthermore, the inhibition of action potentials by increasing the time of the refractory period was demonstrated. Thus, the proof of principle for combined light stimulation and extracellular recording was performed and the high spatiotemporal resolution of this system, which is faster than single AP events, was demonstrated. Combined, this work brings together biology, electronics, materials science, and chemistry to advance the bidirectional communication with simplied networks of electrogenic cells. At the level of recording devices, new materials have been shown capable of detecting cell signals. New methods for interfacing with these materials have been developed with a process that is applicable to other extracellular recording devices as well, while overcoming the challenges of low density cell networks in culture. Finally, a setup was built to integrate non-invasive, light-based cell stimulation with various extracellular recording facilities. |
