Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
20 results
Search Results
Item Cytocompatibility by MTT assay and platelet adhesion of Ti and Ti-6Al-4V coated with hydroxyapatite in different plasma gas atmospheres(Jaypee Brothers Medical Publishers (P) Ltd 4838/24 Ansari Road, Daryaganj New Delhi 110 002, 2017) Kotian, R.; Rao, P.P.; Madhyastha, P.; Shobha, K.L.; Satish Rao, B.S.S.; Ginjupalli, K.Aim: This study was performed to evaluate the biocompatibility of pure titanium and Ti-6Al-4V metals coated with hydroxyapatite (HA) by plasma spray using different plasma gas atmospheres. Materials and methods: The cell viabilities for each HA-coated sample in an atmosphere of argon, argon–hydrogen, nitrogen, and nitrogen–hydrogen were studied using MTT assay and platelet adhesion test. Results: The mean cell viabilities by MTT [3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide] assay of samples coated with HA in argon–hydrogen plasma atmosphere showed maximum cell viability at different time intervals compared with other coating atmospheres of argon–hydrogen, nitrogen, and nitrogen–hydrogen. A statistically significant value of cell viability (p < 0.001) was observed between and within the groups of argon, argon–hydrogen, nitrogen, and nitrogen–hydrogen plasma gas atmosphere. The platelet adhesion study showed agglomerates of platelet cells in some isolated regions of HA for all atmospheres. Significance: The results obtained in this study can serve as a guide for the development of new Ti-based HA-coated implants in different plasma gas atmospheres. © 2017, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.Item X-ray diffraction analysis of hydroxyapatite-coated in different plasma gas atmosphere on Ti and Ti-6Al-4V(Medknow Publications subscription@eurjdent.com B9, Kanara Business Centre, off Link Road, Ghatkopar (E) Mumbai 400 075, 2017) Kotian, R.; Rao, P.P.; Madhyastha, P.Objective: The aim is to study the effect of plasma working gas on composition, crystallinity, and microstructure of hydroxyapatite (HA) coated on Ti and Ti-6Al-4V metal substrates. Materials and Methods: Ti and Ti-6Al-4V metal substrates were coated with HA by plasma spray using four plasma gas atmospheres of argon, argon/hydrogen, nitrogen, and nitrogen/hydrogen. The degree of crystallinity, the phases present, and microstructure of HA coating were characterized using X-ray diffraction and scanning electron microscopy. Results: Variation in crystallinity and the microstructure of HA coating on plasma gas atmosphere was observed. Micro-cracks due to thermal stresses and shift in the 2? angle of HA compared to feedstock was seen. Conclusion: Plasma gas atmosphere has a significant influence on composition, crystallinity, and micro-cracks of HA-coated dental implants. © 2017 European Journal of Dentistry.Item Dissolution and in vitro bioactive properties of BaO added Na2O-CaO-P2O5 glasses(Society of Glass Technology christine@glass.demon.co.uk, 2018) Edathazhe, A.B.; Shashikala, H.D.Na2O-CaO-P2O5 glasses with different additions of BaO were subjected to dissolution tests in deionised water and in vitro bioactivity tests in phosphate buffer saline (PBS) as well as Hank's balanced salt (HBS) solution. Phosphate glasses of composition (26-x)Na2O-xBaO-29CaO-45P2O5 (x=0, 5, 10, 15 mol%) were prepared by melt-quenching. The dissolution characteristics of these glasses were studied in deionised water under static conditions based on BaO composition. The dissolution rate of the glasses in deionised water decreased with BaO content. The in vitro bioactivity tests were carried out in PBS and HBSS for 28 days under static conditions. The bioactivity of the samples was verified by XRD, SEM/EDS and FTIR techniques. Hydroxyapatite phases were formed on all the glass samples within seven days of immersion in HBSS and the bioactivity was found to improve with BaO content. The glasses without BaO and with 15 mol% BaO showed the hydroxyapatite phases within the immersion of 14 days in PBS whereas the glasses with 5 and 10 mol% BaO showed formation of amorphous hydroxyapatite phases. © 2018 Society of Glass Technology. All rights reserved.Item Corrosion resistance and in-vitro bioactivity of BaO containing Na2O-CaO-P2O5 phosphate glass-ceramic coating prepared on 316 L, duplex stainless steel 2205 and Ti6Al4V(Institute of Physics Publishing helen.craven@iop.org, 2018) Edathazhe, A.B.; Shashikala, H.D.The phosphate glass with composition 11Na2O-15BaO-29CaO-45P2O5 was coated on biomedical implant materials such as stainless steel 316 L, duplex stainless steel (DSS) 2205 and Ti6Al4V alloy by thermal enamelling method. The structural properties and composition of glass coated substrates were studied by x-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive x-ray spectroscopy (EDS) analysis. The coatings were partially crystalline in nature with porous structure and pore size varied from micro to nanometer range. The polarization curve was obtained for uncoated and coated substrates from electrochemical corrosion test which was conducted at 37 °C in Hank's balanced salt solution (HBSS). The corrosion resistance of 316 L substrate increased after coating, whereas it decreased in case of DSS 2205 and Ti6Al4V. The XRD and SEM/EDS studies indicated the bioactive hydroxyapatite (HAp) layer formation on all the coated surfaces after electrochemical corrosion test, which improved the corrosion resistance. The observed electrochemical corrosion behavior can be explained based on protective HAp layer formation, composition and diffusion of ions on glass coated surfaces. The in-vitro bioactivity test was carried out at 37 °C in HBS solution for 14 days under static conditions for uncoated and coated substrates. pH and ion release rate measurements from the coated samples were conducted to substantiate the electrochemical corrosion test. The lower ion release rates of Na+ and Ca2+ from coated 316 L supported its higher electrochemical corrosion resistance among coated samples. Among the uncoated substrates, DSS showed higher electrochemical corrosion resistance. Amorphous calcium-phosphate (ACP) layer formation on all the coated substrates after in-vitro bioactivity test was confirmed by XRD, SEM/EDS and ion release measurements. The present work is a comparative study of corrosion resistance and bioactivity of glass coated and uncoated biomedical implants such as 316 L, DSS and Ti6Al4V. © 2018 IOP Publishing Ltd.Item Interfacial bonding of plasma-coated hydroxyapatite on titanium and Ti-6AI-4V(Jaypee Brothers Medical Publishers (P) Ltd 4838/24 Ansari Road, Daryaganj New Delhi 110 002, 2018) Kotian, R.; Rao, P.; Madhyastha, P.Aim: The study aimed to understand the interfacial bonding and diffusion of elements between substrate metal and HA-coated titanium implants in different plasma gas atmosphere. Materials and methods: Commercially pure titanium and Ti-6Al-4V substrate metals were coated with hydroxyapatite by plasma spray in plasma gas atmospheres of argon, argon/ hydrogen, nitrogen, and nitrogen/hydrogen. The microstructure and interfacial bonding between the metal substrate and HA coating were studied by scanning electron microscopy, energy dispensive X-ray analysis (EDAX), and X-ray diffraction. Results: The analyses of the coatings obtained showed a different microstructural pattern of HA and diffusion of elements across the interface of metal and HA coating and chemical bonding for all plasma gas atmospheres. Conclusion: The plasma-coating atmosphere influences the microstructure and crystallization of HA. Diffusion of elements from metal substrate to HA coating and coating to metal surface indicate chemical bonding between the metal and coating in addition to usual mechanical bonding. Clinical significance: Bonding between the metal substrate and HA coating play a significant role in the stability of the dental implant. In addition to mechanical bonding, the plasma coated implants show some amount of chemical bonding at the interface. © 2018, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.Item Faster Biomineralization and Tailored Mechanical Properties of Marine-Resource-Derived Hydroxyapatite Scaffolds with Tunable Interconnected Porous Architecture(American Chemical Society service@acs.org, 2019) Hadagalli, K.; Panda, A.K.; Mandal, S.; Basu, B.Although hydroxyapatite (HA)-based porous scaffolds have been widely researched in the last three decades, the development of naturally derived biomimetic HA with a tunable elastic modulus and strength together with faster biomineralization properties has not yet been achieved. To address this specific issue, we report here a scalable biogenic synthesis approach to obtain submicron HA powders from cuttlefish bone. The marine-resource-derived HA together with different pore formers can be conventionally sintered to produce physiologically relevant scaffolds with porous architecture. Depending on pore formers, the scaffolds with a range of porosity of up to 51% with a larger range of pore sizes up to 50 ?m were fabricated. An empirical relationship between the compression strength and the elastic modulus with fractional porosity was established. A combination of moderate compressive strength (12-15 MPa) with an elastic modulus up to 1.6 GPa was obtained from cuttlefish-bone-derived HA with wheat flour as the pore former. Most importantly, the specific HA scaffold supports the faster nucleation and growth of the biomineralized apatite layer with full coverage within 3 days of incubation in simulated body fluid. More importantly, the marine-species-derived HA supported better adhesion and proliferation of murine osteoblast cells than HA sintered using powders from nonbiogenic resources. The spectrum of physical and biomineralization properties makes cuttlefish-bone-derived porous HA a new generation of implantable biomaterial for potential application in cancellous bone regeneration. © 2019 American Chemical Society.Item Hydroxyapatite—a promising sunscreen filter(Springer, 2020) Pal, A.; Hadagalli, K.; Bhat, P.; Goel, V.; Mandal, S.Exposure to ultraviolet (UV) radiation has been known to cause skin cancer, erythema, and sunburn. Continuous efforts have been made to make sunscreens more efficient and non-toxic. Inorganic sunscreens like TiO2 and ZnO are continued to be used for a few decades, and they are efficient in giving protection against harmful UV radiation, but they are photochemically active as well. They generate free radicals upon irradiation, which leads to reactive oxygen species (ROS) generation which is harmful to the human skin. Hydroxyapatite (HA) is a biocompatible material as it has a composition the same as the mineral content of the human bone; therefore, it is suitable for the dermatological application. Though HA itself does not provide protection against UV, studies on doped HA with various ions showed excellent performance. Pure HA absorbs only between 200 and 340 nm, with an intense band below 247 nm. HA doped with bivalent Zn2+, Fe2+, and trivalent Fe3+ and Cr3+, showed absorbance in the entire UV region. TiO2 provides absorbance in the entire UV range, while ZnO does so only in UVA. Compared to HA (refractive index, n = 1.6), TiO2 (n = 2.6) and ZnO (n = 1.9) have higher refractive index, which gives unwanted whitening effect. Additional properties can be brought in HA composites by adding material while retaining their individual properties. As HA is not photocatalytic, it does not lead to a generation of free radicals. This paper throws light on several aspects of HA-based sunscreen filters as an emerging future cosmetic material, and brief analysis and conclusions. © 2019, Australian Ceramic Society.Item Combustion aided in situ consolidation of high strength porous ceramic structures with a minimum thermal budget(Elsevier B.V., 2020) Pujar, P.; Pal, A.; Mandal, S.The exothermic reaction between a pair of combustible pore formers (urea-ammonium nitrate) is the driving force in realizing low-temperature consolidation of hydroxyapatite (HA) particles. The particles are allowed to sinter in the proximity to the combustible pore formers. The exothermic (?H°rea = -898 kJ/mol) redox reaction between combustible pore formers is successfully utilized in deriving high compressive strength (~24 MPa) of HA at 300 °C. The evolution of gaseous products of combustion results in an interconnected porous network of HA. The estimated compressive strength of sintered HA at 300 °C is comparable with high temperature (1100 °C) conventionally sintered HA, at a fixed open porosity (~40%); which depicts nearly ~82% achievement with a reduction of sintering temperature by ~72%. Also, the pellets sintered at 600 °C have shown ~90% achievement in compressive strength of sintered HA. Further, the saturated pore area of 15% requires a sintering time of 9.58 h at a sintering temperature of 600 °C. Thus, combustion-assisted sintering is an alternative technique proves its potentiality in achieving remarkable compressive strength and paves the way for low-cost porous ceramics. © 2020 Elsevier B.V.Item Effect of Fe3+ substitution on the structural modification and band structure modulated UV absorption of hydroxyapatite(Blackwell Publishing Ltd, 2021) Hadagalli, K.; Shenoy, S.; Shakya, K.R.; Manjunath, G.; Tarafder, K.; Mandal, S.; Basu, B.The effect of Fe3+ ionic substitution in hydroxyapatite (Ca10-xFex(PO4)6(OH)2) was studied using structural modifications, resulting in an improvement in UV absorption through a tailored optical band structure. Ca2+ of HA being larger compared to Fe3+ contributes to the shrinkage of the lattice. Undoped HA has a peak at 1085 cm?1 (?3 PO43?) which is shifted to 1033 cm?1 for Fe-HA, because of the perturbation in HA structure. An improvement of UV absorption in the entire UVA and UVB range with an increase in Fe content because of a decrease in bandgap from 5.9 eV to 2.1 eV with undoped and doped HA. Theoretically obtained band gap and optical behaviour of the systems are well correlated with the experimental findings. Moreover, the use of marine biowaste from cuttlefish bone, as the source of HA; low cost and promising UV absorption can have a potential application as UV protective sunscreen filters. © 2020 The American Ceramic SocietyItem Comparative investigation of coating and friction stir processing on Mg-Zn-Dy alloy for improving antibacterial, bioactive and corrosion behaviour(Elsevier B.V., 2021) Rokkala, U.; Jana, A.; Bontha, S.; Ramesh, M.R.; Balla, V.K.Magnesium based alloys are well-known materials for temporary implant applications. However, failures due to early degradation and bacterial infection are limiting their applications. To overcome these problems, in the present work a Mg-Zn-Dy alloy based composite surface was prepared using coating and friction stir processing (FSP) techniques. Herein, hydroxyapatite (HA) and silver (Ag) particles were deposited on Mg-Zn-Dy alloy to obtain HA and Ag coated surface (C-HAg). Later, FSP was carried out on the C-HAg surface to develop a Mg-Zn-Dy alloy based composite surface (F-HAg). Field emission scanning electron microscope (FESEM) and energy dispersive X-ray analysis (EDS) confirm the mixing of HA and Ag particles with the Mg-Zn-Dy substrate. Antibacterial studies reveal that both C-HAg and F-HAg samples inhibit Escherichia coli and Staphylococcus aureus bacteria. In vitro cytotoxicity study indicates that the both samples are non-toxic in nature. Results of in vitro corrosion study reveal a significant reduction (72%) in corrosion rate of F-HAg sample when compared to C-HAg sample. The F-HAg samples showed simultaneous improvement in corrosion resistance and antibacterial properties with good biocompatibility. The results of this study indicate that the developed composite surface is a promising material for antibacterial and biodegradable implant applications. © 2021 Elsevier B.V.