scholarly journals PROMISING COMPOSITE MATERIALS BASED ON NANOSCALE APATITE WITH GELATIN AS A BINDING AGENT

2021 ◽  
pp. 664-671
Author(s):  
Екатерина Анатольевна Богданова ◽  
Владимир Михайлович Скачков
Keyword(s):  
Colloidal Suspension ◽  
Aqueous Suspension ◽  
Gelatin Solution ◽  
Binding Agent ◽  
Porous Films ◽  
Bioactive Coatings ◽  
Bioactive Material ◽  
Bioactive Coating ◽  
High Adhesion ◽  
Patent Applications

Порошки наноразмерных гидроксиапатита и фторапатита синтезированы методом осаждения из растворов. В качестве связующего вещества использован пищевой желатин. Такая композиция имеет высокую адгезию на материалах различной природы и пористости. Получены также пористые пленки и гранулы с развитой удельной поверхностью. Рассмотрены их микроструктуры. Изучена возможность использования коллоидной суспензии и водной суспензии кристаллического апатита в сочетании с раствором желатина в качестве биоактивного материала, как для создания покрытий, так и получения гранул. Установлено, что использование порошка апатита совместно с желатином позволяет существенно сократить сроки формирования биоактивного покрытия и значительно повысить его адгезионную прочность. Сопоставлены получаемые гранулы апатита по размерам в зависимости от концентрации желатина в водном растворе. На разработанные биоактивные покрытия и гранулированный материал на основе наноразмерного апатита со связующим агентом поданы заявки на патент. Nanoscale hydroxyapatite and fluorapatite powders were synthesized by precipitation from solutions. Food gelatin is used as a binder. This composition has a high adhesion on materials of different nature and porosity. Porous films and granules with a developed specific surface area were also obtained. Their microstructures are considered. The possibility of using a colloidal suspension and an aqueous suspension of crystalline apatite in combination with a gelatin solution as a bioactive material, both for creating coatings and obtaining granules, has been studied. It is established that the use of apatite powder together with gelatin can significantly reduce the time of formation of a bioactive coating and significantly increase its adhesive strength. The obtained apatite granules are compared in size depending on the concentration of gelatin in an aqueous solution. Patent applications have been filed for the developed bioactive coatings and granular material based on nanoscale apatite with a binding agent.

scholarly journals Bioactive coating of zirconia toughened alumina ceramic implants improves cancellous osseointegration

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anne-Marie Pobloth ◽  
Max J. Mersiowsky ◽  
Luisa Kliemt ◽  
Hanna Schell ◽  
Anke Dienelt ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Carbonate Apatite ◽  
Implant Surface ◽  
Bioactive Coatings ◽  
Bioactive Coating ◽  
Ceramic Implants ◽  
Push Out ◽  
Zirconia Toughened Alumina

Abstract Bioactive coatings have the potential to improve the bony integration of mechanically loaded orthopedic ceramic implants. Using the concept of mimicking the natural bone surface, four different coatings of varying thickness on a zirconia toughened alumina (ZTA) ceramic implant were investigated regarding their osseointegration in a drill-hole model in sheep. The hypothesis that a bioactive coating of ZTA ceramics would facilitate cancellous bone integration was investigated. The bioactive coatings consisted of either a layer of covalently bound multi phosphonate molecules (chemical modification = CM), a nano hydoxyapatite coating (HA), or two different bioactive glass (BG) coatings in micrometer thickness, forming a hydroxyl-carbonate apatite layer on the implant surface in vivo (dip-coated 45S5 = DipBG; sol-gel 70S30C = SGBG). Coated surfaces were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. After 12 weeks, osseointegration was evaluated via mechanical push-out testing and histology. HA enhanced the maximum push-out force (HA: mean 3573.85 ± 1119.91 N; SGBG: mean 1691.57 ± 986.76 N; p = 0.046), adhesive shear strength (HA: mean 9.82 ± 2.89 MPA; SGBG: mean 4.57 ± 2.65 MPA; p = 0.025), and energy release rate (HA: mean 3821.95 ± 1474.13 J/mm2; SGBG: mean 1558.47 ± 923.47 J/mm2; p = 0.032) compared to SGBG. The implant-bone interfacial stiffness increased by CM compared to SGBG coating (CM: mean 6258.06 ± 603.80 N/mm; SGBG: mean 3565.57 ± 1705.31 n/mm; p = 0.038). Reduced mechanical osseointegration of SGBG coated implants could be explained histologically by a foreign body reaction surrounding the implants.

scholarly journals Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 122 ◽  
Author(s):  
Diogo V. Saraiva ◽  
Ricardo Chagas ◽  
Beatriz M. de Abreu ◽  
Cláudia N. Gouveia ◽  
Pedro E. S. Silva ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Near Infrared ◽  
Colloidal Suspension ◽  
Aqueous Suspension ◽  
Composite Films ◽  
Helical Structure ◽  
Infrared Region ◽  
Hydroxypropyl Cellulose ◽  
Chiral Nematic ◽  
Chiral Nematic Structure

Lyotropic colloidal aqueous suspensions of cellulose nanocrystals (CNCs) can, after solvent evaporation, retain their chiral nematic arrangement. As water is removed the pitch value of the suspension decreases and structural colour-generating films, which are mechanically brittle in nature, can be obtained. Increasing their flexibility while keeping the chiral nematic structure and biocompatible nature is a challenging task. However, if achievable, this will promote their use in new and interesting applications. In this study, we report on the addition of different amounts of hydroxypropyl cellulose (HPC) to CNCs suspension within the coexistence of the isotropic-anisotropic phases and infer the influence of this cellulosic derivative on the properties of the obtained solid films. It was possible to add 50 wt.% of HPC to a CNCs aqueous suspension (to obtain a 50/50 solids ratio) without disrupting the LC phase of CNCs and maintaining a left-handed helical structure in the obtained films. When 30 wt.% of HPC was added to the suspension of CNCs, a strong colouration in the film was still observed. This colour shifts to the near-infrared region as the HPC content in the colloidal suspension increases to 40 wt.% or 50 wt.% The all-cellulosic composite films present an increase in the maximum strain as the concentration of HPC increases, as shown by the bending experiments and an improvement in their thermal properties.

scholarly journals The Role of Growth Factors in Bioactive Coatings

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1083
Author(s):  
Dragana Bjelić ◽  
Matjaž Finšgar
Keyword(s):  
Tissue Engineering ◽  
Growth Factors ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Healing Process ◽  
Therapeutic Agents ◽  
Ageing Population ◽  
Bioactive Coatings ◽  
Bioactive Coating ◽  
Advantages And Disadvantages

With increasing obesity and an ageing population, health complications are also on the rise, such as the need to replace a joint with an artificial one. In both humans and animals, the integration of the implant is crucial, and bioactive coatings play an important role in bone tissue engineering. Since bone tissue engineering is about designing an implant that maximally mimics natural bone and is accepted by the tissue, the search for optimal materials and therapeutic agents and their concentrations is increasing. The incorporation of growth factors (GFs) in a bioactive coating represents a novel approach in bone tissue engineering, in which osteoinduction is enhanced in order to create the optimal conditions for the bone healing process, which crucially affects implant fixation. For the application of GFs in coatings and their implementation in clinical practice, factors such as the choice of one or more GFs, their concentration, the coating material, the method of incorporation, and the implant material must be considered to achieve the desired controlled release. Therefore, the avoidance of revision surgery also depends on the success of the design of the most appropriate bioactive coating. This overview considers the integration of the most common GFs that have been investigated in in vitro and in vivo studies, as well as in human clinical trials, with the aim of applying them in bioactive coatings. An overview of the main therapeutic agents that can stimulate cells to express the GFs necessary for bone tissue development is also provided. The main objective is to present the advantages and disadvantages of the GFs that have shown promise for inclusion in bioactive coatings according to the results of numerous studies.

scholarly journals CELLULOSE FIBERS SHOW PROMISE IN REDUCING SUNBURN INJURY OF `PAULARED' APPLES.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 638a-638
Author(s):  
Alvan Gaus ◽  
Matthew Rogoyski
Keyword(s):  
Vegetative Growth ◽  
Corn Starch ◽  
Colloidal Suspension ◽  
Cellulose Fibers ◽  
Apple Fruit ◽  
Symptom Expression ◽  
Binding Agent ◽  
Direct Sunlight ◽  
The Third ◽  
Fruit Surface

A set of 3 experiments was conducted to determine if cellulose fibers (CF) could reduce the incidence of sunburn injury in `Paulared' apples. Sunburn injury was artificially increased in these experiments by fruit manipulation and removal of shading vegetative growth to expose apples to at least 4 hours of direct sunlight. The 4 treatments applied included an unsprayed control, a commercial binding agent (CBA), a 1% corn starch (CS) colloidal suspension, and a 3% CF suspension that contains CBA and CS. No differences between treatments were found in the first experiment. The CF suspension concentration was increased to 9% for the second experiment. This resulted in uneven CF distribution on the fruit surface and no significant differences between treatments. The third experiment was designed to more precisely determine sunburn symptom expression by delineating the manipulated fruit surface area directly exposed to sunlight prior to treatment. The resulting percent of area that showed a white (bleached) sunburn symptom was significantly less for the apple fruit treated with CF than CBA alone.

In Situ Polymerization Synthesis of Ternary Sulfur/Polypyrrole/Graphene Nanosheet Cathode for Lithium/Sulfur Batteries

2016 ◽  
Vol 847 ◽  
pp. 8-13 ◽  
Author(s):  
Xin Yi Liu ◽  
Yue Li ◽  
Yan Zhao ◽  
Hai Peng Li ◽  
Fu Xing Yin ◽  
...  
Keyword(s):  
Aqueous Suspension ◽  
Rate Capability ◽  
Composite Cathode ◽  
Graphene Nanosheet ◽  
Adhesion Ability ◽  
High Adhesion ◽  
Pyrrole Monomer ◽  
Lithium Sulfur Batteries ◽  
Specific Discharge

A novel sulfur/polypyrrole/graphene nanosheet composite (S/PPy/GNS) was synthesized and investigated as a promising cathode material. This ternary composite was prepared via in situ polymerization of pyrrole monomer with nanosulfur and GNS aqueous suspension followed by heat-treatment. Scanning electronic microscopy observation revealed the formation of a highly porous structure consisting sulfur and polypyrrole coating on the GNS surface. In this composite, GNS works as nanocurrent collector and enhances the conductivity of the composite, and polypyrrole with its high adhesion ability to GNS could act as a binder to connect sulfur and GNS. The resulting S/PPy/GNS composite cathode exhibits high and stable specific discharge capacities of 991 mAh g-1 after 50 cycles at 0.1 C and good rate capability.

scholarly journals Bioactive composite gradient coatings of nano-hydroxyapatite/polyamide66 fabricated on polyamide66 substrates

2012 ◽  
Vol 9 (72) ◽  
pp. 1450-1457 ◽  
Author(s):  
Di Huang ◽  
Yi Zuo ◽  
Jidong Li ◽  
Qin Zou ◽  
Li Zhang ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Polymeric Matrix ◽  
Bone Tissue Regeneration ◽  
Gradual Transition ◽  
Chemical Corrosion ◽  
Bioactive Coating ◽  
High Adhesion ◽  
Coating Method ◽  
Coating Methods ◽  
Convenient Technique

Tightly bonding of bioactive coating is the first crucial need for orthopaedic implants. This study describes a novel and convenient technique to prepare bioactive coating with high adhesion on orthopaedic substitutes made of polymeric matrix. Here, a chemical corrosion method has been adopted to fabricate a coating on the surface of injection-moulded polyamide66 (PA66) substrates by corrosive nano-hydroxyapatite/polyamide66 (n-HA/PA66) composite slurry. Scanning electron microscopy observation shows that a porous chemical corrosion region presents between the coating and dense PA66 substrate. Energy-dispersive X-ray spectroscopy analysis indicates that the chemical corrosion region is mainly composed of PA66 matrix, and the coating layer is an n-HA-rich layer. Both the pore size and n-HA composition increase gradually from the polymeric substrate towards the coating surface. Mechanical testing shows the bonding strength can reach 13.7 ± 0.2 MPa, which is much higher than that fabricated on polymeric matrix by other coating methods. The gradual transition in coating structure and composition benefits for the interface bonding and for the surface bone-bonding bioactivity. Subsequent cell experiments corroborate n-HA-rich coating and a porous structure is benefitting for cell attachment and proliferation. The convenient coating method could be popularized and applied on similar polymer implants to produce a tightly and porous bioactive coating for bone tissue regeneration.

Concentrated crystallization of closely packed colloidal crystal films from aqueous suspension immersed in silicone oil

2010 ◽  
Vol 1273 ◽  
Author(s):  
Hiroshi Fudouzi ◽  
Tsutomu Sawada ◽  
Lucien Brush
Keyword(s):  
Self Assembly ◽  
Silicone Oil ◽  
Colloidal Crystal ◽  
Colloidal Suspension ◽  
Aqueous Suspension ◽  
Optical Microscope ◽  
Close Packed Structure ◽  
Crystal Film ◽  
Crystal Films ◽  
Working Distance

AbstractColloidal crystals have been attracting much attention due to their novel use as 3D-photonic crystals and to their structural color. We have been developing a method for the colloidal crystal growth of opal films immersed in silicone oil. This method is one of the evaporative self-assembly techniques for opal films from colloidal particle suspensions. Understanding the mechanism of the process is important to assure the coating of high-quality opal thin films. The colloidal crystallization from suspension was observed with a long working distance optical microscope and Bragg's diffraction peaks were measured with a miniature fiber optic spectrometer. The transition from a non-crystalline to a crystalline phase is observed within a region between the disordered colloidal suspension and the colloidal crystal film. Within this region, that spans a distance of about 400μm, the lattice of the colloidal crystal reduces until it transitions to the close-packed structure.

Enhancing the Hydrophobicity of a Copper Pipe by Electrophoretic Deposition of Graphene Oxide

2019 ◽  
Vol 801 ◽  
pp. 153-159
Author(s):  
Essam Hares ◽  
Ahmed H. El-Shazly ◽  
M.F. El-Kady ◽  
A.S. Hammad
Keyword(s):  
Thin Film ◽  
Contact Angle ◽  
Graphene Oxide ◽  
Electrophoretic Deposition ◽  
Graphite Oxide ◽  
Colloidal Suspension ◽  
Aqueous Suspension ◽  
Chemical Oxidation ◽  
Operating Voltage ◽  
Copper Pipe

Thin film coatings of graphene oxide (GO) onto copper pipe was investigating using electrophoretic deposition (EPD) technique. Graphite oxide was produced from graphite powder by chemical oxidation using modified Hummers' method. An aqueous colloidal suspension of graphene oxide was prepared by exfoliation of the graphite oxide via ultrasonic treatment. GO coatings were deposited on copper pipes through EPD from GO aqueous suspension. The EPD parameters such as voltage, time and particle concentration were optimized to obtain uniform GO coatings. The optimal EPD conditions for well-formed deposits were observed when the operating voltage was equal to 30 V and 90 s deposition time. The thin film coated copper pipe was characterized using various techniques such as SEM, XRD and contact angle. XRD confirmed that GO was reduced during the EPD process itself due to the removal of oxygen containing functional groups. SEM images elucidated the formation of GO thin layer onto copper pipe with thickness 5 μm. The contact angle improved from 70° for bare copper to 102.4° for GO coating.

TEM observation of iron oxide pillars in montmorillonite

1990 ◽  
Vol 48 (4) ◽  
pp. 882-883
Author(s):  
H. Mori ◽  
Y. Murata ◽  
H. Yoneyama ◽  
H. Fujita
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Fine Particles ◽  
Aqueous Suspension ◽  
Volume Ratio ◽  
Exchange Capacity ◽  
Nano Composites ◽  
Pillared Montmorillonite ◽  
Topographic Features ◽  
Transmission Electron

Recently, a new sort of nano-composites has been prepared by incorporating such fine particles as metal oxide microcrystallites and organic polymers into the interlayer space of montmorillonite. Owing to their extremely large specific surface area, the nano-composites are finding wide application[1∼3]. However, the topographic features of the microstructures have not been elucidated as yet In the present work, the microstructures of iron oxide-pillared montmorillonite have been investigated by high-resolution transmission electron microscopy.Iron oxide-pillared montmorillonite was prepared through the procedure essentially the same as that reported by Yamanaka et al. Firstly, 0.125 M aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate, [Fe3(OCOCH3)7 OH.2H2O]NO3, was prepared and then the solution was mixed with an aqueous suspension of 1 wt% clay by continuously stirring at 308 K. The final volume ratio of the latter aqueous solution to the former was 0.4. The clay used was sodium montmorillonite (Kunimine Industrial Co.), having a cation exchange capacity of 100 mequiv/100g. The montmorillonite in the mixed suspension was then centrifuged, followed by washing with deionized water. The washed samples were spread on glass plates, air dried, and then annealed at 673 K for 72 ks in air. The resultant film products were approximately 20 μm in thickness and brown in color.

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