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1

The Effect of Phosphates and Fluorides, Included in TiO2 Nanotube Layers on the Performance of Hydrogen Peroxide Detection

Arkusz K., Krasicka-Cydzik E.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

765--772

EN

Titania nanotube (TNT) arrays fabricated by anodizing of titanium foil in organic (ethylene glycol) and inorganic (phosphoric acid) electrolytes and thermally modified in argon revealed much improved properties to detect hydrogen peroxide. Horseradish peroxidase and acetate thionine co-absorbed by a dip coating on the TNT electrode were used to detect hydrogen peroxide in phosphate buffered saline. The morphology and electrochemical properties of TNT arrays were studied by scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. Well defined oxidation and reduction peaks for potassium ferricyanide have been observed for TNT formed in ethylene glycol and annealed in argon. TNT arrays formed in organic electrolyte and annealed in argon indicated more favorable adsorption and electrochemical properties what was confirmed by detection of hydrogen peroxide towards analyte in phosphorate buffered saline solution.

2

Functionalized nanotubular oxide layer on Ti6Al4V as a regulator and biosensor of bone tissue remodeling

Kaczmarek-Pawelska A., Krasicka-Cydzik E.

Archives of Materials Science and Engineering

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2015

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Vol. 73, nr 2

53--61

EN

Purpose: Our aim was to obtain functionalized nanotubular oxide layer (TNTs) on Ti6Al4V alloy and evaluate its efficiency as a platform for electrochemical biosensor of bone remodeling markers. It was also crucial to examinate does the amount of bonded bALP and BMP-2 and antibodies depends from nanotubes diameter and their electrochemical properties. Design/methodology/approach: The antibody specific for bALP and BMP-2 were used to functionalize the TNTs on Ti6Al4V. The spectrophotometry and electrochemical measurements (CV and EIS) were used to examinate the functionalization efficiency and comfirmed sensing properties of the functionalized TNTs on Ti6Al4V alloy. Findings: The obtained results confirmed that TNTs can strongly bind antibodies by physioabsorption and may be a proper platform for biosensing of the selected markers. The protein immobilization efficiency depends over the nanotube diameter and their electrical charge. Thermally modified TNTs with 50 nm diameter on Ti6Al4V strongly bind bALP antibodies and bALP and it can be detected amperometrically. BMP-2 quantitatively binds to the functionalized non annealed charged TNTs with 100 nm diameter, and it is possible to detect it using EIS. Research limitations/implications: The biosensors presented in this work are simple and fast, but this construction is a prototype and need to be optimized to be used in bone remodelling diagnostics. Practical implications: Development of the functionalized TNTs on the Ti6Al4V sensitive for physiological concentrations of the bone remodelling markers may be alternative for immunotests in diagnostic of bone diseases. Moreover the TNTs morphology generates nano roughness over the Ti6Al4V surface and functionalized by antibodies strongly bind bALP or BMP-2 and stimulate bone proliferation. Originality/value: Unique value of this research is the statement the amount of bonded markers and antibodies depends from TNTs diameter and electrochemical properties, and that the prototype of novel biosensor electrode was developed.

3

Elektrochemiczna detekcja interleukiny-6 na podłożu nanotubularnym ditlenku tytanu

Arkusz K., Nycz M., Paradowska E., Krasicka-Cydzik E.

Engineering of Biomaterials

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2014

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Vol. 17, no. 125

21--29

PL

Celem przeprowadzonych badań było opracowanie elektrochemicznych biosensorów do wykrywania obecności prozapalnej cytokiny, interleukiny 6 (IL-6), w roztworze soli fizjologicznej buforowanej fosforanami (phosphate bufferred saline PBS). Do tego celu wykorzystano nowe, modyfikowane powierzchniowo warstwy nanorurek ditlenku tytanu (TNT – titania nanotubes) wytworzone w procesie anodowania folii tytanu w roztworze glikolu etylenowego. Warstwy TNT poddano obróbce termicznej poprzez wyżarzanie w atmosferze argonu i funkcjonalizowano przez bezpośrednią immobilizację przeciwciał cytokiny IL-6 na ich powierzchni metodą nakraplania. Oznaczenie stężenia IL-6 w roztworze PBS badano za pomocą dwóch typów biosensorów elektrochemicznych: impedancyjnego i amperometrycznego, wykorzystując oddziaływania pomiędzy ludzkim przeciwciałem monoklonalnym IL-6 i antygenem IL-6. Działanie biosensora impedancyjnego polegało na określeniu zmian wartości pojemności elektrycznej warstwy powierzchniowej (a równocześnie kąta przesunięcia fazowego jej charakterystyki impedancyjnej) na skutek powstawania kompleksu antygen-przeciwciało IL-6. Do wykrywania antygenu IL-6 w biosensorze amperometrycznym zastosowano natomiast przeciwciało IL-6 skoniugowane z peroksydazą chrzanową (HRP). Limity detekcji IL-6 opracowanych biosensorów wynoszące 5 pg/ml są znacznie niższe od limitu detekcji w obecnie stosowanych testach immunoenzymatycznych ELISA (25 pg/ml). Zarówno korzystne właściwości adsorpcyjne i dobre przewodnictwo elektryczne materiału podłoża biosensorów, umożliwiającego zastosowanie bezpośredniej immobilizacji substancji biologicznych, jak i stosowane dwie metody elektrochemiczne: impedancyjna oraz amperometryczna sprawiają, że opracowana metoda detekcji cytokin jest szybka, tania, selektywna i czuła.

EN

Sensitive electrochemical biosensors for determination of proinflammatory cytokine Interleukin-6 are elaborated. They are based on novel and surface modified layers of titania nanotubes (TNT) formed by anodization of titanium foil in ethylene glycol solution. The TNT layers were thermally improved by annealing in argon and functionalized for biosensing by direct immobilization of biological reagents on their surfaces with the simple drop technique. Strong antibody-antigen interaction was used in two types of electrochemical biosensors: the impedimetric and the amperometric to detect the IL-6 concentrations in phosphate buffered solutions (PBS). The impedimetric biosensor determines changes of capacitance values due to the formation of IL-6 antibody-antigen complex on biosensor platform. Horseradish peroxide (HRP) conjugated antibodies are used to detect IL-6 antigen in the amperometric biosensor. Two novel electrochemical methods allow to detect 5 pg/ml of IL-6 in PBS solution, which is below detection limit 25 pg/ml in currently used enzyme-linked immunosorbent assay (ELISA) tests. The favorable adsorption and electrical conductance properties of the platform material, which allow the direct immobilization of biological substances on its surface and give the possibility to apply two electrochemical techniques: the impedimetric and the amperometric one, ensure the elaborated cytokine detection methods to be fast, inexpensive, selective and sensitive.

4

Model matematyczny do wyznaczania parametrów formowania nanorurek TiO2 podczas anodowania

Krasicka-Cydzik E., Arkusz K., Kaczmarek A.

Engineering of Biomaterials

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2012

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Vol. 15, no. 114

34--40

PL

Celem badań było opracowanie modelu matematycznego opisującego formowanie nanorurek z tlenku tytanu (TNT) na folii tytanowej metodą anodowania. Równania uwzględniające wpływ parametrów anodowania na wybrane cechy morfologiczne TNT posłużą do wyznaczania i optymalizowania parametrów anodowania: potencjału, czasu i stężenia składnika organicznego elektrolitu, w celu uzyskania TNT o pożądanej średnicy i długości. W pracy stosowano dwa organiczne elektrolity - glikol etylenowy i glicerol, resztę stanowiła woda z dodatkiem 0,65% wag. NH4F. Wynikiem pracy są równania i wykresy opisujące zależności pomiędzy parametrami anodowania (dane wejściowe), a cechami morfologicznymi TNT (dane wyjściowe). Poprawność modelu została sprawdzona poprzez ocenę morfologii TNT wytworzonych zgodnie ze wskazaniami modelu. Wyniki potwierdzają możliwość przewidywania średnicy i długości TNT, tj. grubości ich warstwy na folii tytanowej na podstawie modelu. W celach aplikacyjnych konieczne jest udoskonalenie przedstawionego modelu poprzez redukcję błędów.

EN

A mathematical model to determine parameters of anodic formation of titania nanotubes (TNT) on titanium foil has been elaborated. Equations include the influence of voltage, time of anodization and concentration of organic component of electrolyte on the selected morphological features of TNT: diameter and length of nanotubes. The developed model can be used to predict and optimize the anodization parameters to obtain nanotubes of desired diameter and length. Two organic electrolytes, ethylene glycol and glycerol, have been used, the rest of electrolyte being water with addition of 0.65 wt% NH4F. The equations and graphs showing the correlations between the anodizing and morphological parameters are presented. The correctness of the model has been tested by comparing the parameters of produced nanotubes with parameters indicated by the model. Results confirm the possibility to predict the diameter and the length of TNT formed by anodizing of titanium in two organic solutions with small addition of fluorides and obtain TNT of desired morphology for biomedical applications.

5

Effect of fluorides on bioactivity of titania nanotubes in SBF solution – by EIS studies

Krasicka-Cydzik E., Białas-Heltowski K., Głazowska I., Klekiel T., Kaczmarek A.

Archives of Materials Science and Engineering

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2011

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Vol. 51, nr 1

33-39

EN

Purpose: The influence of fluorides concentration in anodizing electrolyte on deposition of calcium phosphates Ca-O-P on titania nanotubes immersed in simulated body fluid (SBF) has been examined. Design/methodology/approach: The electrochemical impedance spectroscopy (EIS) was used to monitor the process of deposition of calcium phosphates on titanium foils covered with titania nanotubes formed by anodizing in 1 M H3PO4 with various amounts of fluorides ranging from 0.2 wt% to 0.4 wt%. The changes in impedance characteristics combined with results of SEM and EDS analyses were used to evaluate the bioactivity of nanotubes in SBF and find out the relation between the morphology of deposits and the concentration of fluorides in the anodizing electrolyte. Findings: The obtained results confirmed that titania nanotubes strongly favour the deposition of calcium phosphates (HAp) during the first 24 hours. However, the behavior of titania nanotubes formed in the electrolytes of various fluoride content differ afterwards when immersed longer in SBF solution. Particularly, contrary to other samples, the amount of deposits on nanotubes formed in 1 M H3PO4+0.30% wt. HF decreases significantly about 72 hours after immersing and these observations are recorded by both the SEM/EDS examination and XPS results. The corresponding changes in impedance parameters are noticed. Practical implications: Development of the method to cover titanium implant materials with nanoporous anodic layer, enriched in phosphates and fluorides- both ions highly supporting bioactivity, enables new applications in implantology and biosensing. Originality/value: Bioactivity is highly desirable property of implant materials. The phenomena observed during immersion in SBF solution by the Electrochemical Impedance Spectroscopy are related to the amount of fluorine in titania nanotubes. The explanation of this behavior and its consequence to bioactivity is proposed.