Novel bioceramics have an intriguing role in implants and prostheses as surface protecting agents. These bioceramics have promising features such as biocompatible, bioactive, and corrosion-resistant ...natures. Among bioceramics, silica glass and its composite unravel its better desirability against corrosion and wear with interfacial bone bonding capability in physiological systems by nucleating calcium phosphates over the surface, thereby enhancing the osteoinductive property. In the current study, SiO2 and ZnO were obtained by processing silica and zinc oxide precursors at low temperature using low thermal volatilization sol-gel method. SiO2, ZnO, and its composite powders were characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX). Electrophoretic deposition (EPD) was used for coating on Ti-6Al-4V for improved coating characteristics. In addition, the effect of additives such as iodine and Polyvinylpyrrolidone (PVP) on coating limits was also optimized. Thin-film XRD, Optical Microscopy, SEM-EDAX, Raman spectroscopy, and the scratch resistance test characterized the coating. Tafel polarization and electrochemical impedance spectroscopy (EIS) studies were also carried out to assess corrosion resistance behaviour of the coating. The results showed that the composite coating has greater corrosion resistance than uncoated Ti-6Al-4V. Furthermore, improved mechanical property with better scratch resistance was also observed. These observations showed that composite coating could be useful in biomedical applications.
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•Pure SiO2 and its composite with ZnO were coated on Ti-6Al-4V by EPD using PVP-K30, iodine as additives.•ZnO, an antibacterial, lubricating material acted as a pore plugging for porous SiO2 coating.•10mg of iodine in the composite has produced more corrosion resistance with enhanced adhesion than SiO2 coating.
Glass-ceramic was prepared by sol–gel method using Ca(NO3)2·4H2O and P2O5 as Ca and P precursors, respectively. In order to improve the bioactivity of the implant material, glass-ceramic (β-Ca2P2O7) ...coating was developed on 316L SS substrate by spin coating method. Coating was annealed at different temperatures and its corrosion resistance was evaluated by electrochemical polarization and impedance analysis using Ringer’s solution as electrolyte. The results from the present study, show excellent corrosion resistance for coated 316L SS, corroborated by the high values of charge transfer resistance from impedance analysis and higher breakdown and repassivation potential with the corresponding lower current density from polarization measurements. Based on the results, the glass-ceramic coating on 316L SS can be considered as a corrosion resistant material.
In the past few years, magnetic nano-particles (magnetite) have captured more attention in the field of biomaterial world.Various methods have been adopted for its synthesis,of which a simple, low ...temperature co-precipitation method was selected and adopted.Synthesized iron oxide magnetic nano-particles encounter limitations such as insolubility, aggregation, high reactivity and biodegradation in biological medium. To enhance the magnetic properties with various limitations, functionalization or encapsulation within the shell by way of surface coating has been recently appreciated by medical scientists. Functionalization or coating by silica has more and easily carried out by sol-gel technique. The encapsulated, core magnetite nano-particles are characterized by Fourier transform infrared spectroscopy (FT-IR), Powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX), Hydrodynamic size and compressive strength. The tweaking results from the above various characterization techniques revealed the formation of well-resolved peak intensity with appealing microstructures and particle size distribution with better compressive strength values. On the basis of these observations, we envision that the iron oxide/silica core-shell magnetic nano-particles is an intersting biomaterial for orthopedical applications.
In this study, for the first time we have developed the composite coatings using sol-gel derived hydroxyapatite HAP: (Ca)10 (PO4)6 (OH)2 and magnetite (Fe3O4) on alkali treated Ti-6Al-4V alloy using ...various concentrations of Fe3O4 nanoparticles such as 1, 3 and 5 wt% respectively. The fabricated composite coatings were characterized by XRD, SEM-EDAX and contact angle measurements. In vitro bioactivity study confirmed that the composite coated Ti-6Al-4V was highly bioactive and induces bone like apatite formation in the presence of Fe3O4 NPs which involves the nucleus formation by developing Fe-OH groups on the surface of coatings. The corrosion resistance study proved that 1 wt% of Fe3O4 with HAP composite coatings exhibit good anticorrosion behaviour than the 3, 5 wt% of composites due to lower Fe-OH groups and uniform with adherent layer which restricts the leaching of ions. Hence, this finding suggested that HAP/Fe3O4 composites coated implants can be used for biomedical applications.
Impact of sintering temperature and aging time was investigated on purity and phase of hydroxyapatite powders synthesized through sol–gel process. Phase, composition, and morphology of the prepared ...hydroxyapatite powders were characterized using X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR), and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS). Plausible mechanism respective to the formation of HAP from the precursors Ca(NO3)2·4H2O and triethyl phosphite (TEP) by sol–gel process was determined from 31P NMR analysis. Further, the development of hydroxyapatite coatings on 316L SS metallic surfaces was done by varying the spin coating parameters such as spin speed, spin time, and sintering atmosphere, and their corrosion resistance behavior in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and TAFEL polarization analysis. From the results, we inferred that the HAP coatings deposited on 316L SS surfaces at 3000 rpm/min under nitrogen atmosphere sintering have shown improved corrosion resistivity. The effect of aging time, sintering atmosphere, and spin speed was evaluated in terms of corrosion resistance behavior.
The process of bone tissue regeneration involves an intricate network of a biological macromolecules that includes proteins and peptides to support stimulation and healing response.Here,we have ...fabricated a novel flaxseed/silk fibroin based(dual protein)composite nanofibers using β-TCP to improve the biological properties and promote cartilage tissue regeneration along with a controllable rate of biodegradation.The physiochemical properties of PVA/β-TCP/FP:SF were characterized by FTIR,XRD,SEM,porosity,contact angle measurements and mechanical evaluation etc.This study demonstrates the biological performance of the developed nanofibers by using hemocompatibility,biodegradation ability,and apatite deposition in stimulated body fluid.Moreover,the cell viability assay was performed on MG-63 osteoblast cells and long-term antibacterial rate against E.coli and S.aureus was analysed.Docking results of flax protein and silk fibroin protein further confirmed the stable modes of intramolecular bonding and the most stable electrostatic values using theoretical calculations.Taken together,the experimental results proved that the dual protein-based fibrous scaffold was found to be up-regulated in terms of biological activity with enhanced cell adhesion and proliferation.
Achievement of bioactive coatings on metallic implant surface with higher adhesive strength and corrosive resistance was one of the main challenges for the current biomaterial researchers. ...Hydroxyapatite was one of the promising bioactive ceramic which can be applied as a coating on the metallic substrate due to its similarity with the human bone.
The work describes the in-situ preparation of HAP/f-MWCNTs composite by sol-gel method. MWCNTs were functionalized by acid treatment. HAP composites have been prepared by varying the molar percentage of f-MWCNTs from 1% to 5%. The prepared composites with various concentrations of f-MWCNTs were characterized by FT-IR and XRD for its functional group analysis and phase purity. The morphology of the prepared powder was analyzed using SEM and TEM. In-vitro corrosive behavior on SBF was studied for the coating prepared HAP composite sol on 316L SS. The triple layer composite coating was obtained at the spin speed of 3000 rpm/min and subjected to sintering at 500 °C/2 h.
X-ray diffraction results confirmed the formation of pure HAP up to the addition of 3% of f-MWCNTs without any secondary phases. The average crystallite size of the prepared particles was decreased from 40 ± 2.1 to 17 ± 2.5 nm with the addition f-MWCNTs. The morphological studies confirm the incorporation of f-MWCNTs in HAP matrix. The prepared HAP/f-MWCNTs composite efficiently inhibits the growth of the pathogens such as S. Aureus and E.coli. Improved hardness was observed with reinforcement of f-MWCNTs into the hydroxyapatite matrix. Electrochemical studies confirm the HAP/f-MWCNTs composites having increased corrosive resistance properties. The bonding strength of the composite coatings showed improved adhesion to the 316L surface.
In this work we have fabricated sol-gel derived anti-microbial composite coating on the 316L substrate by means of spin coating at optimized conditions with higher adhesive strength and improved corrosion resistance.
Hydroxyapatite and Titania being able to exhibit a plethora of distinct applications related to bone-tissue regeneration and orthopaedic implantations, we consider them as our essential materials ...under concern. The present investigation deals with HAp/TiO.sub.2 composites and its preliminary characterizations based on the results from XRD, FTIR, SEM and further extending the studies to electrophoretic deposition of the composite coating. The results from XRD and FTIR gave a confirmation on the phase transformation studies of TiO.sub.2 from anatase to rutile. HAp inherently exhibits adequate biocompatibility and osteoregenerative applications and hence used extensively for coatings over implants. Composite was made using HAp and TiO.sub.2 to provide a better preferable coating for the orthopaedic implant through electrophoretic deposition technique by varying voltage parameter. From our current study with preliminary outcomes, we confirmed that the HAp/TiO.sub.2 composite is a promising coating and could be opted for biomedical applications.
Donor –linker –acceptor (DSSA) is a concept in fluorescence chemistry with acceptor being a fluorescent compound (FRET) or quencher. The DSSA probes used to measure thiol levels in vitro and in vivo. ...The reduction potential of these dyes are in the range of −0.60 V, much lower than the best thiol reductant reported in literature, the DTT (−0.33 V). DSSA disulphide having an unusually low reduction potential compared to the typical thiol reductants is a puzzle. Secondly, DSSA probes have a cyclized rhodamine ring as acceptor which does not have any spectral overlap with fluorescein, but quenches its absorbance and fluorescence. To understand the structural features of DSSA probes, we have synthesized DSSANa and DSSAOr. The calculated reduction potential of these dyes suggest that DSSA probes have an alternate mechanism from the FRET based quenching, namely hydrophobic interaction or dye to dye quenching. The standard reduction potential change with increasing complexity and steric hindrance of the molecule is small, suggesting that ultra- low Eo’ has no contribution from the disulphide linker and is based on structural interactions between fluorescein and cyclized rhodamine. Our results help to understand the DSSA probe quenching mechanism and provide ways to design fluorescent probes.
The current work focused on the development of hydroxyapatite (HAP) coating on laser textured metallic implants using electrophoretic deposition. HAP was synthesized by sol-gel technique and its ...phase purity and surface morphology were confirmed by FT-IR, XRD and SEM analysis. 316L SS and Ti-6Al-4V metal implants were polished and the surface was modified using Nd-YAG laser operating at a pulse interval of 10ns at various overlapping rate of 0%, 25% and 50%. The laser treated surface was characterized for its surface roughness using surface profilometry and surface morphology. The surface roughness of the metallic implants was increased by increase in the overlapping rate. The prepared HAP powder was electrophoretically deposited on bare and laser textured Ti-6Al-4V and 316L stainless steel followed by vacuum sintering at 300°C for 2h. Scratch analysis results showed an improvement in adhesion strength for the HAP coatings on laser treated specimens than untreated metal. Corrosion efficiency of the coated samples was studied in SBF solution using EIS and potentiodynamic polarization studies. The result from the corrosion experiments proved increased corrosion resistance property of laser textured coated samples when compared to bare alloy due to higher adhesion of HAP coating on the metal surface.
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