Advanced biomimetic implants based on nanostructured coatings synthesized by pulsed laser technologies.

Calcium Phosphates (CaPs) are alternative substitutes for human bones and so primary candidates for the manufacturing of medical implants. Unfortunately, they do not withstand stress in bulk. To overcome this obstacle, a solution was developed to cover the metallic implants with functional biomimetic layers. Pulsed laser deposition (PLD) proved to be a competitive method to grow high-quality biomaterial thin films. Nevertheless, in case of very complex delicate biomolecules (such as organic and biopolymeric materials), PLD provokes an irreversible damage of the chemical bonds and thus the compositional change in the deposited film. This disadvantage is eliminated by matrix assisted pulsed laser evaporation (MAPLE), capable to transfer large molecular mass compounds at very low temperatures. We review in this chapter the potential of PLD applied to different types of simple and/or doped CaP coatings. We also scrutinize the extension of MAPLE to the synthesis of hybrid organic-inorganic bionanocomposites for advanced biomimetic implants. Expected development and progress of the new in-vitro and in-vivo studies are discussed

Measurements of quantum efficiency of MG films produced by pulsed laser ablation deposition for application to bright electron sources

We report the results of preliminary tests on Mg film photocathodes deposited by pulsed laser ablation deposition on various substrates. A comparison with other deposition techniques is presented. We illustrate briefly the technique of deposition of thick films (up to several microns). Scanning electron microscope analysis of the films before and after laser cleaning has been performed to characterize the changes occurred on the surface. Measurements of the distribution and integrated value of quantum efficiency over the illuminated surface are reported. Plans for the deposition on the back flange of an RF gun are illustrated

A SPEED SENSORLESS DIGITALLY CONTROLLED INDUCTION MOTOR DRIVE ESTIMATING ROTOR RESISTANCE VARIATION

We review recent results on biomaterial nanostructured layers transferred by matrix-assisted pulsed laser evaporation (MAPLE). The chapter is organized according to three main applications of these nanostructures: drug delivery systems, biosensing and biomimetic coating of metallic implants. The synthesized layers were optimized based upon the results of investigations performed by physical\u2013chemical methods. Biocompatibility and bioactivity were assessed by dedicated in vitro tests. From the first category we chose the composite alendronate\u2013hydroxyapatite (HA). The coating of metallic implants with these layers demonstrated to enhance human osteoblasts proliferation and differentiation, while inhibiting osteoclasts growth, with benefic effects for the treatment of osteoporosis. Enzyme ribonuclease A (RNase A) immobilized on solid supports has applications in control of the enzymatic reaction, and improved stability as compared to the free enzyme. The results by reversed-phase high-performance liquid chromatography showed that immobilization process does not affect the RNase A behavior. The transfer of pure levan and oxidized levan was obtained by MAPLE without any addition of plasticizers or pigments. The nanostructures exhibited high specific surface areas fully compatible with their potential use in drug delivery systems. For the second application, we refer to the transfer and immobilization of IgG molecules. We investigated the effect of the lipid addition in the initial solution upon the protein thin films adhesion to substrates. From the third class, we selected magnesium substituted octocalcium phosphate (OCP) and strontium substituted OCP deposited by MAPLE on Ti substrates which proved to enhance osteoblast activity and differentiation. We conclude that under optimized conditions, the thin films obtained by MAPLE were similar in composition, morphology and structure with the base material, and most likely preserved their functionality and biological performances

Photoemission Characteristics of PLD Grown Mg Films under UV Laser Irradiation

In this paper we report a detailed description of the laser cleaning procedure and emission performance measurement on a pulsed laser deposited Mg film. During the tests performed after the end of each cleaning operation we have observed an increase in quantum efficiency (QE) in time. Then the QE apparently stabilizes at a remarkably higher value. The study of this phenomenon and its relation to chemical composition of the residual gases of vacuum environment is important because it determines both the achievable QE value and the lifetime of the Mg film based cathode. Moreover, the stability of the QE at remarkably high values has been revealed for a time scale of several days after each laser cleaning process, in our vacuum conditions. The adsorption of reactive chemical species leading to the lowering of the Mg work function is discussed