Electrodeposition of Chitosan on Ti-6Al-4V Surfaces: A Study of Process Parameters (original) (raw)
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Enhancement of adhesion strength and in-vivo evaluation of electrodeposited calcium phosphate/chitosan biocoatings on titanium substrate, 2023
Chitosan/calcium phosphate nanocomposites are widely used as a biocompatible coatings for titanium bioimplants in the fields of dentistry and orthopedics to enhance the integration between the implants and the hard bone. However, the poor adhesion strength between the coating and the metal substrate was found to be one of the major problems in the clinical application of these implants. In the current study, we reported the formation of Ca/P coating on titanium (Ti) substrate using electrodeposition. The key factor of the bath ingredients is the change of chitosan's solvent from a commonly used acetic acid to acrylic acid in the electrolyte. The structural analysis including X-ray diffraction (XRD), Raman spectroscopy, and attenuated total reflectance (ATR) confirmed the formation of three phases of Ca/P octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD) brushite, and hydroxyapatite (HA). The bond strength was performed by the tape test (ASTM D3359-09) which showed that nearly 65% of the coatings were removed in the case of using 2, 4, and 6% (v/v) acetic acid as chitosan solvent, while only 5% of the coatings were removed when high concentrations (4 and 6%) of acrylic acid is used in addition to increasing of the surface wettability. Furthermore, the morphology and thickness of the calcium phosphate layer coated on the surface of Ti metal were inspected by scanning electron microscopy (SEM). Finally, an in vivo application was conducted on the optimized coating by surgically placing the coated and control discs into rats' clavicular bones for 2-weeks healing period. Then biomechanical evaluation was performed to verify the effect of treatment on the interface resistance to shear force, and histological analysis was performed to evaluate the bone tissue reactions to coated discs. The results showed that using acrylic acid instead of acetic acid to dissolve chitosan before in-situ electrodeposition might be an innovative approach to enhance the adhesion strength between chitosan/calcium phosphate-based coatings and titanium metal to be used in orthopedic and dental implant technology.
A Novel Photocrosslinkable and Cytocompatible Chitosan Coating for Ti6Al4V Surfaces
Journal of Applied Biomaterials & Functional Materials, 2015
Background In this work, chitosan (CH) was used to produce a novel coating for Ti6Al4V, the most widely used alloy in orthopedic implants, so as to improve the biological tissue response at the metallic surface. Methods The Ti6Al4V surface was sandblasted with alumina particles. CH was chemically modified, via carbodiimide chemistry, using lactobionic and 4-azidebenzoic acid to make it soluble at physiological pH and photocrosslinkable, respectively. The reaction was verified by FTIR, NMR and UV/vis spectroscopy. Ti6Al4V surfaces were coated with solutions of the modified CH and exposed to UV light, causing polymer crosslinking and formation of a hydrogel on the surface. The crosslinking reaction was monitored by FTIR at different exposure times. Coating morphology was observed by SEM. The coating's cytocompatibility was determined in vitro through the culture of rat bone marrow mesenchymal stem cells, using an MTT assay, with their morphology assessed by SEM. Results The develo...
The International Journal of Advanced Manufacturing Technology
Biomedical implants interact with human tissues introducing significant perturbation into the body. Implant surfaces can be then functionalized enabling better biocompatibility. At the same time, the additional use of a coating provides further functions such as corrosion protection, osteointegration, and drug delivery. In this context, a composite made of chitosan and bioactive glass nanoparticles has been used for coating Ti6Al4V alloy samples processed beforehand using different processes, i.e., polishing, milling, grit blasting, and electrical discharge machining. Experiments have been carried out to correlate substrate surface conditions and coating effectiveness in terms of scratch resistance with the final aim to obtain suitable guidelines to improve substrate-coating performances. Graphical Abstract
Progress in Organic Coatings, 2018
Chitosan, chitosan/45S5 bioactive glass (mBG), chitosan/nanobioglass (nBG), and chitosan/mBG/nBG coatings were deposited on grit-blasted and mirror-polished Ti6Al4 V alloy substrates by electrophoretic deposition (EPD). This study discusses how the surface characteristics of the substrates influence the 3D surface topography, areal surface roughness, morphology, and wettability of chitosan-based thin composite coatings while focusing on tuning the surface characteristics by grit-blasting. The surfaces of coated and uncoated specimens were characterised by SEM analysis with EDX, image analysis, contact angle measurements, 3D surface topography analysis, FTIR analysis, and in-vitro bioactivity studies. The coatings deposited on grit-blasted substrates presented rougher surface topography, higher areal surface roughness values and wettability compared to the mirror-polished surfaces. A deposition mechanism was suggested to clarify the deposition of chitosan/mBG coatings on grit-blasted substrates. Apatite crystals were formed on chitosan/mBG coatings after immersion in SBF for three days. A robust image analysis method was applied to reveal the distribution and area coverage percent of deposited mBG, which demonstrated the increase of mBG coverage with the increases in voltage. The present study shows that grit blasting could be a favourable surface treatment to tailor the surface characteristics of organic-inorganic composite coatings by influencing their surface topography, roughness, and wettability.
Electrochemical deposition of bioactive coatings on Ti and Ti–6Al–4V surfaces
Surface and Coatings Technology, 2011
Passivating coatings of brushite (CaHPO 4 •2H 2 O) were obtained on Ti and Ti-6Al-4V ELI alloy substrates by cathodic polarization. After soaking in Ringer's solution for 48 h brushite was transformed to hydroxyapatite (Ca 10 (PO 4) 6 (OH) 2) as confirmed by XRD, FT-IR and Raman spectroscopy. Electrochemical cyclic polarization curves of the coated biomaterials obtained in Ringer's solution at pH values of 7.1 and 8.91 as well as in Hank's Balanced Salt Solution (HBSS) at pH value of 7.4 show a nobler behavior than of the uncoated biomaterials. The coated biomaterials had lower corrosion rates than the uncoated biomaterials suggesting a protective character of the hydroxyapatite coating. Electrochemical impedance spectra (EIS) revealed capacitive behavior, owing to the protective, very resistant layer, the thickness of which increased with soaking time. The coated biomaterials presented higher electropositive open circuit potentials compared to the uncoated biomaterials as result of the protective effect of the coating. The morphology of the coatings changed with soaking time as the coatings became denser, smoother and better adhering. Hence such coatings may provide favorable structure for cell adhesion and proliferation.
Electrophoretic Deposition and Characterisation of Chitosan Coatings on Near-Β Titanium Alloy
Archives of Metallurgy and Materials, 2016
In this study, chitosan coatings were electrophoretically deposited (EPD) on near-β Ti-13Nb-13Zr alloy. The influence of colloidal solution composition and EPD parameters on the quality of chitosan coatings was investigated. It was established that the uniformity of as-deposited chitosan coatings is highly dependent on the chemical composition of the solution used for EPD, the pH, electrophoretic mobility and zeta potential of chitosan colloidal molecules, as well as EPD parameters, such as potential difference value and deposition time. The microstructure of the coatings was investigated using electron microscopy and X-ray diffractometry. The coatings 350 nm thick were homogeneous and exhibited an amorphous structure. The coatings had low hardness and Young’s modulus. The effect of surface of the substrate preparation prior to coating deposition on the adhesion of chitosan coatings to the Ti-13Nb-13Zr alloy was also investigated. The coatings exhibited good adhesion to the non-acid...
Coatings, 2020
Currently, a significant problem is the production of coatings for titanium implants, which will be characterized by mechanical properties comparable to those of a human bone, high corrosion resistance, and low degradation rate in the body fluids. This paper aims to describe the properties of novel chitosan/Eudragit E 100 (chit/EE100) coatings deposited on titanium grade 2 substrate by the electrophoretic technique (EPD). The deposition was carried out for different parameters like the content of EE100, time of deposition, and applied voltage. The microstructure, surface roughness, chemical and phase composition, wettability, mechanical and electrochemical properties, and degradation rate at different pH were examined in comparison to chitosan coating without the addition of Eudragit E 100. The applied deposition parameters significantly influenced the morphology of the coatings. The chit/EE100 coating with the highest homogeneity was obtained for Eudragit content of 0.25 g, at 10 V, and for 1 min. Young's modulus of this sample (24.77 ± 5.50 GPa) was most comparable to that of human cortical bone. The introduction of Eudragit E 100 into chitosan coatings significantly reduced their degradation rate in artificial saliva at neutral pH while maintaining high sensitivity to pH changes. The chit/EE100 coatings showed a slightly lower corrosion resistance compared to the chitosan coating, however, significantly exceeding the substrate corrosion resistance. All prepared coatings were characterized by hydrophilicity.
Chitosan-Coating Deposition via Galvanic Coupling
ACS Biomaterials Science & Engineering, 2019
A galvanic method to deposit chitosan coatings on stainless steel substrate is reported. Deposition of suitable coatings is desired to improve biocompatibility and corrosion resistance of metallic medical devices to be implanted in human body. In the present work, a thin hydrogel layer of chitosan was deposited on 304SS by a galvanic displacement reaction, which is advantageous firstly as it does not require external power supply. 304SS was immersed into an aqueous solution of chitosan/lactic acid and electrochemically coupled with magnesium acting as a sacrificial anode. SEM images showed the formation of a uniform layer of chitosan with a thickness controlled by deposition time. Corrosion tests in simulating body fluid showed that chitosan coatings shift the corrosion potential of 304 substrates towards nobler values. Finally, the cytotoxicity of the coating was investigated through cell viability assays with osteoblastic cell MC3T3-E1. The results revealed highly satisfying biocompatibility of the coating.
2015
In the present paper, a correlation between the anodizing potential, morphology and thickness of the titanium oxide surfaces formed on Ti as well as the roughness and adhesion degree of mesenchymal cells onto such functionalized surfaces are analysed. Experiments were performed using 20 mm × 10 mm × 1.5 mm Ti plates cut by electroerosion. After chemical polishing in a mixture containing HF, HNO3 and H2SO4 and then passivation in a solution of 10% HNO3, Ti plates were anodized in a 1 mol L -1 H3PO4 solution at a voltage between 40 and 250 V. In all experiments, the anodizing time was 1 minute. The surface morphology of anodized Ti plates was characterized by optical and scanning electron microscopy. As expected, the average thickness of the anodized layer is strongly dependent on the anodizing voltage. Thicknesses ranging between 3.1 (40 V) and 12.6 m (250 V) were obtained. The surface roughness values of the anodized Ti plates ranged between 0.575 (anodizing voltage of 40 V) and 0....