Investigation of Cell-material Interactions by Scanning Probe Microscopy

The morphology of cells changes consistently with the surface where they adhere. As reported in the literature, surfaces with micrometric and nanometric patterns affect the cell morphology, as well as surfaces with peculiar chemical functionalities. In order to control both morphology and chemistry of the surface, mono-molecular layers of small organic molecules (specifically Pentacene, α-sexithiophene and PDI8-CN2) were deposited on SiOx substrates by means of Organic Molecular Beam Epitaxy (OMBE). Through the partial annealing method, SiOx substrates were fully covered with a mono-molecular layer, as confirmed by Atomic Force Microscopy measurements (surface coverage of about 98%). Such molecules enable SiOx substrates to become biocompatible and to have flat morphologies with selective chemical functionalities. Epithelial cells were cultivated on such samples and their structure and shape has been investigated by optical and fluorescence microscope and Scanning Electrochemical Microscopy (SECM). In the last years, Scanning Probe Microscopies (SPM) techniques have been increasingly used to investigate important biological issues. In order to best apply to the characteristics of these techniques in biological and medical fields, the probes used for imaging have to be: i) cheap and disposable as they can be easily contaminated and damaged during their use; ii) small enough to resolve the investigated biological phenomena or object; iii) reproducible in their aspect and imaging capability. In this work a new fabrication method was proposed and the probes obtained comply with all the aforementioned requirements.