Study of neural cells on ultra thin organic semiconductor film

In this work we report the deposition of cells on organic semiconductor ultra-thin films. This is a first step towards the development of active bio/nonbio systems for electrical transduction that could be integrated directly in vitro. Thin films of pentacene molecules, whose thickness was systematically varied between 1 and 50 nm, were grown by high vacuum sublimation. Human astrocytoma cells and NE-4C neural stem cells were grown and maintained in culture in standart condition in medium supplemented. Viability of cells in time was measured as a function of roughness and the characteristic morphology of ultra thin organic film. Optical fluorescence microscope coupled to atomic force microscope was used to monitor the presence, density and shape of deposited cells. Our data shows unambiguously that stem cells can be grown and differentiate on pentacene thin films without causing any apparent damage to the structure and morphology of the organic semiconductor layer. As pioneer experiment organic FET for operating in controlled humidity and under aqueous solution was investigated. The deposition conditions of semiconductor films give the highest field-effect charge mobility. We are implemented OFETs to study changes associated with the interaction between organic semiconductor ultra thin films and biological molecules (such as peptides, DNA) or cells. In order to discriminate the response caused by biological molecules from the ones caused by the solution, it is fundamental to understand the electrical behavior of organic semiconductors in presence of liquid. Electrical properties of such OFETs with different coverage of thin films were investigated. The knowledge on the behavior of biomolecules on different surfaces and other technologically relevant systems has crucial importance to pave the way to the new hybrid technological platform.