RESUMO
Tissue Engineering is a new emerging field that offers many possibilities to produce three-dimensional and functional tissues like ligaments or scaffolds. The biocompatibility of these materials is crucial in tissue engineering, since they should be integrated in situ and should induce a good cell adhesion and proliferation. One of the most promising materials used for tissue engineering are polyesters such as Poly-ε-caprolactone (PCL), which is used in this work. In our case, the bio-integration is reached by grafting a bioactive polymer (pNaSS) on a PCL surface. Using nonlinear microscopy, PCL structure is visualized by SHG and proteins and cells by two-photon excitation autofluorescence generation. A comparative study between grafted and nongrafted polymer films is provided. We demonstrate that the polymer grafting improves the protein adsorption by a factor of 75% and increase the cell spreading onto the polymer surface. Since the spreading is directly related to cell adhesion and proliferation, we demonstrate that the pNaSS grafting promotes PCL biocompatibility.
RESUMO
We experimentally demonstrate the possibility of retrieving the spatial coherence of an infrared source by using an up-conversion interferometer. Sum-frequency generation in Ti-diffused periodically poled lithium-niobate waveguides in both arms of the interferometer is used to convert the infrared into the visible domain. The fringe contrast of the interference pattern in the visible domain permits us to resolve the spatial separation of two uncorrelated pointlike infrared sources, which simulate a binary star. The validity of these measurements is confirmed through a simultaneous comparison with a reference interferometer working in the infrared domain.