The potentiodynamic behaviour of iron in alkaline solutions under carefully controlled perturbation conditions reveals that the overall electrochemical process is more involved than was thought earlier. The electrochemical characteristics of the systems are explained through a series of successive conjugated redox coupks principally involving Fe(&), Fe(OH), gnd FeOOH as limiting stoichiometric species. The yield of soluble species such as either FeO:-or HFeO; increases with the pH. Ageing effects of reactants and products are also distinguished through the potentiodyoamic E/I records.

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The potentiodynamic response of the Ni/alkaline aqueous solution interface in the region of the hydrated normalNifalse(OH)2 to β‐normalNiOOH electrochemical reaction reveals that both species undergo phase transformations. The anodic product from the normalNifalse(OH)2 species involves the formation of three species energetically different which are detected during the electroreduction process. Under well‐defined perturbation conditions, a reasonable set of kinetic parameters pertaining to the anodic process is obtained which is formally interpreted through a consecutive three‐step mechanism of reaction involving a charge transfer, a chemical reaction, and a charge transfer and a proton transfer process. Side reactions involving water take into account the various aging processes of the reaction products.

The electrochemical behaviour of nickel in alkaline aqueous solutions within the anodic potential range yielding Ni(OHh and under different potentiodynamic perturbations profiles has been investigated. The formation of Ni(OHh is characterized by an irreversible anodic current peak which is quantitatively interpreted in terms of a complex reaction pathway involving different hydroxoadsorbed slx.~cies.

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A Plasma electrolytic oxidation (PEO) process was used to produce bioactive coatings on Ti. PEO coatings with Ca/P atomic ratio of 1.7 and 4.0 were fabricated and characterized with respect to their morphology, composition, and microstructure. AC and DC electrochemical tests were used to evaluate the effect of (i) organic additives (amino acids, proteins, vitamins, and antibiotics) in alpha-minimum essential medium (α-MEM) on electrochemical stability of noncoated and PEO-coated Ti and (ii) coating composition, microstructure, and corrosion behavior on the cell response in α-MEM. PEO-coated Ti showed higher corrosion resistance than the noncoated Ti in MEM with and without organic additives by an order of magnitude. The corrosion resistance in α-MEM decreased with time for nonmodified Ti and increased for PEO-coated Ti; the latter was because of the adsorption of the proteins in the coating pores which increased the diffusion resistance. The presence of Ca and P in titanium oxide coating at the Ca/P ratio exceeding that of any stoichiometric Ca-P-O and Ca-P-O-H compounds facilitates faster osteoblast cell adhesion.

Numerous strategies that are currently used to regenerate bone depend on employing biocompatible materials exhibiting a scaffold structure. These scaffolds can be manufactured containing particular active compounds, such as hydroxyapatite precursors and/or different growth factors to enhance bone regeneration process. Herein, we have immobilized calcium phosphate salts (CPS) and bone morphogenetic protein 2 (BMP-2) – combined or alone – into chitosan scaffolds using ISISA process. We have analyzed whether the immobilized bone morphogenetic protein preserved its osteoinductive capability after manufacturing process as well as BMP-2 in vitro release kinetic. We have also studied both the in vitro and in vivo biocompatibility of the resulting scaffolds using a rabbit model. Results indicated that rhBMP-2 remained active in the scaffolds after the manufacturing process and that its release kinetic was different depending on the presence of CPS. In vitro and in vivo findings showed that cells grew more in scaffolds with both CPS and rhBMP-2 and that these scaffolds induced more bone formation in rabbit tibia. Thus chitosan scaffolds containing both CPS and rhBMP-2 were more osteoinductive than their counterparts alone indicating that could be useful for bone regeneration purposes, such as some applications in dentistry.

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