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Kalcijum fosfati (CP), među kojima su amorfni kalcijum fosfat (ACP) i hidroksiapatit (HAp), zajedno sa slojevima Ti i TiO2, pronašli su ogromnu primenu u preventivnoj i regenerativnoj medicini zbog svoje odlične biokompatibilnosti, netoksičnih svojstava i sposobnosti da učestvuju u metaboličnim procesima organizama. U ovom radu je prikazana citotoksičnost multifunkcionalnih i hibridnih kompozitnih prevlaka amorfnog kalcijum fosfata (ACP) i hitozan laktata (ChOL) na ćelijskoj liniji humanih fibroblasta pluća MRC-5. ACP/TiO2 i ACP/TiO2/ChOL prevlake su taložene novim procesom in situ anodizacije/anaforetske depozicije pri konstantnom naponu od 60 V tokom 180 s na 25 ° C. Testovi citotoksičnosti pokazali su da nije bilo značajnog smanjenja preživljavanja zdravih ćelija MRC-5 u kompozitnim uzorcima Ti i ACP/TiO2, dok je došlo do povećanja broja viabilnih ćelija u uzorku ACP/TiO2/ChOL. Pokazano je poboljšanje ćelijske proliferacije, diferencijacije i viabilnosti ćelija. Uzorak koji sadrži ACP/TiO2/ChOL prevlaku pokazao je negativnu citotoksičnost u DET i u MTT testovima. Zabeležen je veći oporavak humanih ćelija fibroblasta pluća MRC-5 u poređenju sa kontrolnim uzorkom posle 48 h oporavka. Iz ovih rezultata može se zaključiti da multifunkcionalna kompozitna prevlaka ACP/TiO2/ChOL nije samo necitotoksična, već prisustvo ChOL-a u prevlaci poboljšava ćelijsku proliferaciju, diferencijaciju i viabilnost ćelija. Na osnovu dobijenih rezultata može se zaključiti da oba kompozitna materijala koji su korišćeni u studijama nisu citotoksični za korišćene ćelijske linije, te da 5 tež.% ChOL-a ima pozitivan efekat na netoksičnost materijala. Na osnovu prikazanih rezultata u ovom radu i prethodnih objavljenih rezultata fizičko-hemijskih i bioaktivnih svojstava kompozitnog materijala ACP/TiO2/ChOL, može se zaključiti da bi dalji razvoj, kao i potencijalne pretkliničke studije bili u velikoj meri opravdani. Calcium phosphates (CP), amongst which amorphous calcium phosphate (ACP) and hydroxyapatite (HAp), along with Ti and TiO2 layers, have found vast applications in preventive and regenerative medicine due to their excellent biocompatibility, nontoxic properties and ability to participate in the normal metabolism of organisms. In this paper cytotoxicity of amorphous calcium phosphate (ACP) and chitosan lactate (ChOL) multifunctional and hybrid composite coatings on MRC-5 human lung fibroblast cell line is presented. ACP/TiO2 and ACP/TiO2/ChOL are deposited by coatings new in situ anodization/anaphoretic deposition process at constant voltage of 60 V for 180 s at 25 °C. Cytotoxicity tests showed that there was no significant decrease in the survival of healthy MRC-5 cells in the Ti and ACP/TiO2 composite samples, while there was an increase in the number of viable cells in the ACP/TiO2/ChOL sample. There is improved cell proliferation, differentiation and cell viability in the later. Sample containing ACP/TiO2/ChOL coating showed negative cytotoxicity in both DET and MTT tests. Greater recovery of MRC-5 human lung fibroblasts cells was observed compared to the control sample after 48 h of recovery. From these results, it can be concluded that not only the ACP/TiO2/ChOL multifunctional composite coating is non-cytotoxic, but the presence of ChOL in the coating improves cell proliferation, differentiation and cell viability. Based on the obtained results, it can be concluded that both composite materials used in the studies are non-cytotoxic to the cell lines used, and that 5 wt.% of ChOL has a positive effect on the non-toxicity of the material. Based on presented results in this paper and previous published results of the physicochemical and bioactive properties of the ACP/TiO2/ChOL composite material, it can be concluded that further development as well as potential preclinical studies would be largely justified.

In its pure form, aluminum is easy to process and has a high level of corrosion resistance. However, due to its low strength the possibility of application of pure aluminum is reduced. When alloyed, aluminum alloys are widely used material in construction, different industries, airspace and military. Commercial 7000 series aluminum alloys have zinc as the main alloying element, followed by magnesium. This 7000 aluminum series offers a very high strength when heat-treated, which comes from its composition. The life time of these alloys is reduced due to corrosion damage. It is known that corrosion directly or indirectly affects materials, human health and safety, and it causes global economic and environmental problem. The use of inhibitors in corrosion protection is the simplest, most economical and most efficient approach that is routinely used to ‘reduce’ this problem in industry. The most widely used inorganic inhibitors, such as chromates, are not safe, causing health and safety problems due to their toxicity. Organic compounds have increased interest of the scientific community as potential inhibitors in exchange for the most commonly used. The aim of this study was to investigate new green, eco-friendly inhibitors from the group of amino acid and their combination with lanthanides. For the purposes of this investigation, cerium-cysteine complex was synthesized and analyzed by Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM / EDS), Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) and Linear Sweep Voltammetry (LSV) analyses. SEM/EDS was used for morphological analysis and to determine the composition of the aluminum alloy on which the electrochemical tests have been performed. Electrochemical measurements (PEIS, LSV) were erformed in order to test the inhibitory efficacy in 0.1M NaCl at room temperature. Different concentrations of cysteine and Ce-cysteine complex were examined to optimize the process. The adsorption of the inhibitor follows the Langmuir isotherm, and based on the electrochemical results and calculated thermodynamic potential (Gibbs free energy) it can be concluded that both cysteine and cerium-cysteine complex are mixed type of inhibitors. It can be concluded that both cysteine and Ce-cysteine complex inhibitors satisfactory inhibition effect on aluminum alloy corrosion.

Kalcijum fosfati (CP), među kojima su amorfni kalcijum fosfat (ACP) i hidroksiapatit (HAp), zajedno sa slojevima Ti i TiO2, pronašli su ogromnu primenu u preventivnoj i regenerativnoj medicini zbog svoje odlične biokompatibilnosti, netoksičnih svojstava i sposobnosti da učestvuju u metaboličnim procesima organizama. U ovom radu je prikazana citotoksičnost multifunkcionalnih i hibridnih kompozitnih prevlaka amorfnog kalcijum fosfata (ACP) i hitozan laktata (ChOL) na ćelijskoj liniji humanih fibroblasta pluća MRC-5. ACP/TiO2 i ACP/TiO2/ChOL prevlake su taložene novim procesom in situ anodizacije/anaforetske depozicije pri konstantnom naponu od 60 V tokom 180 s na 25 ° C. Testovi citotoksičnosti pokazali su da nije bilo značajnog smanjenja preživljavanja zdravih ćelija MRC-5 u kompozitnim uzorcima Ti i ACP/TiO2, dok je došlo do povećanja broja viabilnih ćelija u uzorku ACP/TiO2/ChOL. Pokazano je poboljšanje ćelijske proliferacije, diferencijacije i viabilnosti ćelija. Uzorak koji sadrži ACP/TiO2/ChOL prevlaku pokazao je negativnu citotoksičnost u DET i u MTT testovima. Zabeležen je veći oporavak humanih ćelija fibroblasta pluća MRC-5 u poređenju sa kontrolnim uzorkom posle 48 h oporavka. Iz ovih rezultata može se zaključiti da multifunkcionalna kompozitna prevlaka ACP/TiO2/ChOL nije samo necitotoksična, već prisustvo ChOL-a u prevlaci poboljšava ćelijsku proliferaciju, diferencijaciju i viabilnost ćelija. Na osnovu dobijenih rezultata može se zaključiti da oba kompozitna materijala koji su korišćeni u studijama nisu citotoksični za korišćene ćelijske linije, te da 5 tež.% ChOL-a ima pozitivan efekat na netoksičnost materijala. Na osnovu prikazanih rezultata u ovom radu i prethodnih objavljenih rezultata fizičko-hemijskih i bioaktivnih svojstava kompozitnog materijala ACP/TiO2/ChOL, može se zaključiti da bi dalji razvoj, kao i potencijalne pretkliničke studije bili u velikoj meri opravdani. Calcium phosphates (CP), amongst which amorphous calcium phosphate (ACP) and hydroxyapatite (HAp), along with Ti and TiO2 layers, have found vast applications in preventive and regenerative medicine due to their excellent biocompatibility, nontoxic properties and ability to participate in the normal metabolism of organisms. In this paper cytotoxicity of amorphous calcium phosphate (ACP) and chitosan lactate (ChOL) multifunctional and hybrid composite coatings on MRC-5 human lung fibroblast cell line is presented. ACP/TiO2 and ACP/TiO2/ChOL are deposited by coatings new in situ anodization/anaphoretic deposition process at constant voltage of 60 V for 180 s at 25 °C. Cytotoxicity tests showed that there was no significant decrease in the survival of healthy MRC-5 cells in the Ti and ACP/TiO2 composite samples, while there was an increase in the number of viable cells in the ACP/TiO2/ChOL sample. There is improved cell proliferation, differentiation and cell viability in the later. Sample containing ACP/TiO2/ChOL coating showed negative cytotoxicity in both DET and MTT tests. Greater recovery of MRC-5 human lung fibroblasts cells was observed compared to the control sample after 48 h of recovery. From these results, it can be concluded that not only the ACP/TiO2/ChOL multifunctional composite coating is non-cytotoxic, but the presence of ChOL in the coating improves cell proliferation, differentiation and cell viability. Based on the obtained results, it can be concluded that both composite materials used in the studies are non-cytotoxic to the cell lines used, and that 5 wt.% of ChOL has a positive effect on the non-toxicity of the material. Based on presented results in this paper and previous published results of the physicochemical and bioactive properties of the ACP/TiO2/ChOL composite material, it can be concluded that further development as well as potential preclinical studies would be largely justified.

The medical devices based on titanium and its alloys are widely used in the repair and replacement of a degraded or inhibited func-tion of locomotor system [1]. Ti and its alloys exhibit high mechanical strength, good workability, resistant to corrosion and low cost. Although, they are widely used as orthopedic and dental implants their inability to interact with living tissue will inhibit their biological fixation and osseoin-tegration [2]. Therefore, to improve the hard-tissue compatibility of Ti various sur-face treatments have been developed for the inorganic coating formation [3]. The hyd-roxyapatite (HAp, Ca10(PO4)6(OH)2) with superior osteogenic activity is a competitive approach to make novel coatings for titanium implants applications. HAp is a calcium phosphate very similar to the inorganic part of the human bone and hard tissues both in morphology and compo-sition. Herein, in-situ synthesis of HAp/TiO2 coating on titanium was performed via ana-phoretic deposition of HAp and simulta-neous anodization of Ti to produce highly adherent and strengthened composite coating. It can be seen that morphology of Ti substrate of anHAP/TiO2 coating is of tubular shape, and tube formation occurs mainly due to competing processes of anodization and electrophoretic deposition of HAp. anHAp/TiO2 coating does not need sintering process, and simultaneous Ti anodization and HAp deposition occur, where HAp crystals incorporate in the anodized Ti surface. From the presented results it can be concluded that novel suggested process of in situ simultaneous anHAp/TiO2 deposition with Ti surface anodization gives much better results that cathaphoretic deposition regarding adhesion.

New biopolymers’ materials, suitable for the adsorption of noble metal ions, were synthesized by chemical and electrochemical modification of biopolymers. Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose was Y = 80.7%, and the degree of substitution of cellulose acrylate of DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with azoisobutyronitrile initiator in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerizations of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone, 9-vinylcarbazole, cellulosepoly-4-vinylpyridine, cellulose-poly-1-vinylimidazole, cellulose-poly-1-vinyl-2-pyrrolidinone and cellulose-poly-9-vinylcarbazole were performed. Cellulose acrylate and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass%) were determined. The grafed copolymers of cellulose with 4-vinylpyridine and 1- vinylimidazole were reacted with methyl iodide and the corresponding 1 - methylpyridinium iodide and 3-methylimidazolium iodide copolymers of cellulose were obtained. Copolymers were transformed into new polymeric reagents, differing in anions (ClO4-, CF3COO-, NO3-, p-TsO-, BF4-, PF6-) by usage of different supporting electrolyte carrying the desired anions through the ion-exchange-electrochemical oxidation of the released iodide at a controlled anodic potential. The thermal stability of cellulose and some of its grafed copolymers with 4-vinyl pyridine in ionic form were studied in nitrogen atmosphere by non-isothermal thermogravimetry in the temperature interval 50-800°C at heating rate of 10°C/min and 80°C/min. Comparasion of the obtained thermogravimetric curves indicated the different thermal stability of cellulose, cellulose-4- vinylpyridine and its ionic derivates. The starting cellulose sample has had the highest thermal stability, while the copolymers in ionic form started to degrade at lower temperatures. There were also differences in the amount of carbonaceous residues at 550°C and 760°C. Grafted copolymers of cellulose were synthesized and tested for sorption of gold and palladium from acid aqueous solutions. The following grafted copolymers cellulose-poly-4-vinyl-pyridine, cellulose-1-methyl-poly-4-vinyl-pyridinium iodide and cellulose-1-methyl-poly-4-vinyl pyridinium three fluoroacetate were synthesized. Characteristcs of grafted cellulose copolymers such as: capacity, degree of sorption in the solution from the process for copper electrolysis were determined. The quantity of gold and palladium were determined by atomic apsorption spectrophotometry. The degree of sorption of all samples of grafted copolymers was more than 99 mass %, indicating that the sorption was good and took place in a period of one hour. Cellulosepoly-4-vinyl-pyridine showed the selectivity due to sepatarion of Au and Pd in regard to Cu and Fe. The capacities of cellulose copolymers for Au and Pd sorptions were determined. Grafted cellulose copolymers suitable for sorption of gold have potential to be used in cancer nanotechnology. Optimization of cellulose acrylate synthesis has been applied as a model for the synthesis of the grafted copolymers of lignin and tannin with vinyl monomers and it can be applied on lignocellulose, starch, chitin, chitosan, proteins and peptides. Synthesis and characterization of electroconductive composite materials prepared by the compression molding of mixtures of lignocellulose and electrochemically deposited copper powder under different pressures is presented. Investigation of the influence of particle size on conductivity and percolation threshold of obtained composites was carried out. Electrodeposited copper powder content was varied from 2.0-29.8 vol. %. Analyses of the most significant properties of individual components and prepared composites included structural and morphological analysis and measurements of hardness and electrical conductivity. The significant increase of the electrical conductivity could be observed as the copper powder content reached the percolationthreshold. The packaging effect and effective interpartical contact with smaller, highly porous, highly dendritic particles with large values of specific area lead to “movement” of percolation threshold towards lower filler content, which for the particles

Titanium substrates were electrochemically treated by novel in-situ synthesis method to produce anaphoretic hydroxyapatite/titanium oxide (HAp/TiO2) coating. This synthesis method was performed via anaphoretic deposition of hydroxyapatite and simultaneous anodization of Ti in order to produce highly adherent and strengthened composite coating, where the influence of electric potential, time, electrolyte concentration and pH value of the anodization process on titanium surface roughness and adhesion strength of composite HAp/TiO2 coatings was examined. In situ synthesis was performed in different solutions containing different concentrations of NaOH, HAp and ethanol at different values of time and constant voltage. The effects of anodizing voltage on the morphology and bioactivity of the HAp coating and on the bonding strength between the HAp coating and the anodized substrates were investigated. A modified chemical precipitation method was used to prepare hydroxyapatite powder by the reaction of stoichiometric amount of calcium oxide and phosphoric acid. Prior to novel in situ synthesis of HAp/TiO2 composite coatings, optimization of anodization process of titanium was performed. Anodization was executed under different electric potentials and different distances of counter electrodes from working electrodes, but all experiments had constant quantity of electric charge. Results indicated that highly ordered amorphous TiO2 surface is formed on the Ti substrate after anodic oxidation. Characterization of titanium samples having rectangular contact surfaces of 10×10×0.89 mm included SEM/EDS analyses, X-ray diffraction analyses, AFM surface topography, morphology and roughness analyses and linear measurements of roughness. The prepared coatings were characterized by FE-SEM, XRD and EDS. Adhesion was investigated by ASTM D 3359–97 Test method B. Uniform and adherent HAp/TiO2 composite coating on Ti was obtained. The results of simulated body fluid immersing experiments suggest that obtained HAp coating exhibits promising bioactivity. The obtained coating can be good candidate for bone implants due to improved adhesion.

In-situ synthesis of HAp/TiO2 coating on titanium was performed via anaphoretic deposition of HAp and simultaneous anodization of Ti to produce highly adherent and strengthened composite coating. The prepared coatings were characterized by field emission scanning electron microscopy, X-ray diffraction and electron dispersive spectroscopy. HAp on anodized titanium was prepared at constant voltage of 60 V and deposition time of 45 s, which provided uniform and adherent HAp/TiO2 composite coating on Ti. Since smaller size of HAp crystals within highly porous coating structures is of improved binding ability to various biomolecules, our coating is expected to be of excellent coverage and compactness. The obtained coating can be good candidate for bone implants due to reduced brittleness and improved adhesion.

The optimization of the anodization process of Ti substrate for in situ synthesis of hydroxyapatite/titanium oxide composite coatings on titanium substrate was accomplished. The anodization was performed under 30, 60 and 90 V cell voltage, and the morphology of treated surface, as well as linear and surface roughness, were analysed by field emission-scanning electron micro­scopy, atomic force microscopy and roughness tester. It was shown by linear and surface roughness analyses that titanium anodized under 60 V has the high­est roughness, whereas at 90 V the flattening of the surface occurs. As the highest surface roughness results emerged at 60 V, the novel process of com­po­site anHAp/TiO2 coating synthesis, which comprises simultaneous processes of TiO2 formation and HAp deposition, as well as HAp impregnation within TiO2 surface layer, was performed at this voltage. Ti substrate surface was completely covered by composite coating, with no visible cracks. The adhesion quantified according to ASTM D3359-02 standard is considerably improved with respect to the coatings obtained by cathaphoretic processes, with no need of subsequent sintering. Процесом анодизације титанског супстрата у циљу накнадне in-situ анафортеске синтезе композитних превлака хидроксиапатит/титан-оксид формиран је оксидни слој на титанској подлози. Анодизација је рађена на напонима на ћелији од 30, 60 и 90 V, а испитивани су морфологија третиране површине, као и линеарна и површинска храпавост, помоћу FE-SEM, AFM и тестера храпавости, редом. Анализом линеарне и површинске храпавости показано је да титан анодизован на 60 V има највећу храпавост, док при анодизацији на 90 V долази до равнања површине. Како је највећа храпавост површине добијена при анодизацији на 60 V, нови процес композитне синтезе anHAp/TiO2 превлака, који се састоји од истовремених процеса формирања TiO2, анафоретског таложења HAp и уградње HAp у ТiО2 матрицу, изведен је при овом напону. Површин титанске подлоге је била потпуно покривена композитном превлаком, без видљивих пукотина, док је адхезија, квантификована ASTM D3359-02 стандардом, знатно побољшана у поређењу са истим превлакама добијеним катафоретским процесима, чак и без накнадног синтеровања превлаке.

Composite materials nowdays are increasing industrial applications worldwide. Composites based on polymers with conductive fillers are getting wider research focus primarily because of their growing importance from the point of application in: electronics, medicine, industry and so on. Besides mentioned above, these composites have found application as contact conductive materials, electromagnetic and radio wave shields, photothermal optical recorders, electronic noses sensitive to certain chemicals, as well as economically acceptable catalysts. The results of experimental studies of the properties of composite materials based on lignocellulosic (LC) and Poly(methyl methacrylate) (PMMA) matrices filled with electrolytic copper are presented in this chapter. Volume fractions of metal fillers in tested composite materials were varied in the range of 1.6–30% (v/v), and the samples were prepared both by compression – cold pressing and hot moulding. The results have shown that shape and morphology of the copper powder, and filler at all, play a significant role in the phenomenon of electrical conductivity of the prepared samples, as well as on the appearance of percolation threshold. The particles with highly developed free surface areas like dendrites, having highly branched structures (such as electrolitically obtained copper powder particles) can much easier form interparticle contacts at lower filler volume fractions than the particles with more regular surface. Layered electrical conductivity throughout the entire sample volume was observed, whereby the resistance of the inner layers was the leading processes of the entire composite resistance. It can be seen that the resistance has increased due to increased contribution of the polymer matrix inner surface area as the frequency decreased. Conductivity measurements have shown typical S-shaped dependence with the percolation transition from nonconductive to conductive region. For all the processing pressures, the percolation threshold for smaller particle sizes was lower than for larger ones. This difference has increased with the increase of processing pressure. A significant increase in the electrical conductivity have been observed when the content of conductive filler in the composites reached the percolation threshold. The effect of particle packaging and pronounced interparticle contact with smaller, highly porous and dendritic particles with large specific surface areas, led to a “shift” of percolation threshold to lower values of filler volume fractions. It was noticed that this transition occurred at lower values of filler content than it was stated in the literature, which is due to the use of fillers with large specific surface areas.

In-situ synthesis of hydroxyapatite/titanium oxide (HAp/TiO2) coating on titanium was performed via anaphoretic deposition of hydroxyapatite (HAp) and simultaneous anodization of Ti to produce highly adherent and strengthened composite coating. The influence of electric potential, time, electrolyte concentration and pH value of the anodization process on titanium surface roughness and anodization of titanium was examined, as well as influence of same process parameters on adhesion strength and compactness of composite HAp/TiO2 coatings was investigated. Prior to novel in situ method of synthesis of hydroxyapatite/titanium oxide composite coatings by simultaneous anodization/anaphoretic electrodeposition described in this manuscript, optimization of anodization process of titanium was performed. Anodization was executed under different electric potentials and different distances of counter electrodes from working electrodes, but all anodization processes had constant quantity of electric charge. Characterization of titanium samples, prepared from grade 6 Ti, and having rectangular contact surfaces of 10×10×0.89 mm included SEM/EDS analyses, X-ray diffraction analyses, AFM surface topography, morphology and roughness analyses and linear measurements of roughness. A chemical precipitation method was used to prepare hydroxyapatite powder by the reaction of calcium oxide (obtained by calcination of CaCO3 for 5 h at 1000 °C in air) and phosphoric acid. A stoichiometric amount of the calcium oxide was stirred in distilled water and phosphoric acid was added drop wise to the suspension in order to obtain hydroxyapatite powder, Ca10(PO4)6(OH)2. Two types of HAp coatings were prepared, in order to compare the adhesion, morphology and consistency of the HAp and composite HAp/TiO2 on Ti, namely cathaphoretic and anaphoretic coatings, respectively [1,2]. The prepared coatings were characterized by field emission scanning electron microscopy, X-ray diffraction and electron dispersive spectroscopy. Adhesion was investigated by ASTM D 3359 – 97 Test method B. Uniform and adherent HAp/TiO2 composite coating on Ti was obtained. Since smaller size of HAp crystals within highly porous coating structures is of improved binding ability to various biomolecules, our coating is expected to be of excellent coverage and compactness. The obtained coating can be good candidate for bone implants due to improved adhesion.