Fabrication of functional fibronectin patterns by nanosecond excimer laser direct write for tissue engineering applications

Laser direct write techniques represent a prospective alternative for engineering a new generation of hybrid biomaterials via the creation of patterns consisting of biological proteins onto practically any type of substrate. In this paper we report on the characterization of fibronectin features obtained onto titanium substrates by UV nanosecond laser transfer. Fourier-transform infrared spectroscopy measurements evidenced no modification in the secondary structure of the post-transferred protein. The molecular weight of the transferred protein was identical to the initial fibronectin, no fragment bands being found in the transferred protein's Western blot migration profile. The presence of the cell-binding domain sequence and the mannose groups within the transferred molecules was revealed by anti-fibronectin monoclonal antibody immunolabelling and FITC-Concanavalin-A staining, respectively. The in vitro tests performed with MC3T3-E1 osteoblast-like cells and Swiss-3T3 fibroblasts showed that the cells' morphology and spreading were strongly influenced by the presence of the fibronectin spots.

Photoelectron emission from yttrium thin films prepared by pulsed laser deposition

We present the results of our investigation of metallic films as suitable materials for the production of intense electron beams. Thin films of Y prepared for the first time by pulsed laser deposition on Si substrates have been tested as photocathodes in an ultra high vacuum photodiode chamber at 10(-6) Pa. High quantum efficiencies have been obtained for the deposited films, comparable to those of corresponding bulks. The role of the adsorbed gases on the emission performance has been studied. Systematic laser cleaning treatments improved the quantum efficiency (QE) from 10(-6) to 4.5 10(-4). The samples could stay for several months in open air before being tested in a photodiode cell. The deposition process and testing results are presented.