Synthesis of biocompatible calcium-phosphate compositions in ultrasound field

2021 ◽  
Author(s):  
V.B. Akopyan ◽  
V.N. Gorshenev ◽  
E.S. Budoragin ◽  
M.V. Bambura ◽  
M.A. Dragun
Keyword(s):  
Calcium Phosphate ◽  
Energy Density ◽  
Porous Structure ◽  
Living Organism ◽  
Collagen Matrix ◽  
Ultrasonic Field ◽  
White Mouse ◽  
Ultrasound Field ◽  
Freeze Dried ◽  
Self Cleaning

Introduction reflects the great interest of practical restorative medicine in artificial structures that mimic the structure and properties of natural bone tissue that are made from biocompatible composite materials suitable for restoring the integrity of bone elements of the musculoskeletal system. The Introduction also contains the physicochemical foundations and approaches to a new ultrasonic technologies providing accelerated production of a biocompatible composite material, precisely hydroxyapatite particles in a collagen matrix. Experimental part contains a description of methods and equipmets for accelerated production of a hydroxyapatite suspension in the field of a hydroacoustic emitter, which ensures that the cavitation threshold at room temperature is exceeded, at which intense acoustic vortex microflows provide a decrease in diffusion restrictions, accelerating the interaction between reacting components. The reaction is carried out with the simultaneous supply of an aqueous solution of calcium monophosphate hydrate and a suspension of calcium hydroxide. The resulting finished product is separated using an ultrasonic self-cleaning filter, where the same, by nature, microflows allow the implementation of a continuous accelerated separation of synthesized particles in an ultrasonic self-cleaning filter of the installation, where, after separation, the precipitate is also subjected to cleaning. The resulting particles of hydroxyapatite mixed with the solution collagen and homogenized in an ultrasonic field at frequency of 22 kHz and an energy density in the reaction volume from 1 to 10 W / cm3. Obtained homogenate can be easily used to create various implant designs with predetermined sizes and shapes and after freezedrying was transformed in biocompatible composite with a porous structure. To control biocompatibility, samples of this composite in form of thin plate was sewed under the skin into the scruff of white lab rats. A suspension of hydroxyapatite mechanically combined with the collagen during 30 s homogenization by ultrasound at frequency of 22 kHz and at energy density of 3 W / cm3, form a complex that is freeze-dried, after which it can be used to form the biocomposite body with porous structure and with given dimensions and shapes. Subcutaneous implantation of plates of a calcium-phosphate biocomposite with a biodegradable polymer collagen, into the scruff of a laboratory white mouse showed its good biocompatibility with tissues of a living organism, without causing either immediate or delayed adverse events in them.

Tobacco stalk-derived carbon prepared by one-step molten salt carbonization for supercapacitor

2021 ◽  
pp. 2151021
Author(s):  
Yuxuan Liu ◽  
Xinhua Cheng ◽  
Shenghui Zhang
Keyword(s):  
Aqueous Solution ◽  
Energy Density ◽  
Porous Structure ◽  
Molten Salt ◽  
Electrode System ◽  
Rate Performance ◽  
Heteroatom Doping ◽  
Hierarchically Porous Structure ◽  
One Step ◽  
Tobacco Stalk

High-performance capacitive carbon materials, derived from tobacco stalk, were prepared by a one-step carbonization process in molten carbonate. Owing to the high specific surface area (SSA) (1165.9 m2 g[Formula: see text] and heteroatom doping by the activation effect of molten salt medium for 3 h, the as-obtained carbon material with hierarchically porous structure exhibits an ideal capacitive property with delivering specific capacitances of 219.8, 188.0, 176.4, and 168.4 F g[Formula: see text] at 0.2, 0.5, 1, and 2 A g[Formula: see text], respectively, acceptable rate performance with 76.6% capacitance retention in range of 0.2–2 A g[Formula: see text], and good cyclic stability with 93% capacitance retention after 3000 charge–discharge cycles at 1 A g[Formula: see text], as well as energy density of 30.5 Wh kg[Formula: see text] at 0.2 A g[Formula: see text] and power density of 989.6 W kg[Formula: see text] at 2 A g[Formula: see text] in 1 mol L[Formula: see text] H2SO4 aqueous solution using a three-electrode system. Moreover, it delivers specific capacitances of 143.3, 140.2, 137.4, and 134.3 F g[Formula: see text] at 0.2, 0.5, 1, and 2 A g[Formula: see text], respectively, and excellent rate performance with 93.7% capacitance retention in range of 0.2–2 A g[Formula: see text], as well as energy density of 4.9 Wh kg[Formula: see text] at 0.2 A g[Formula: see text] and power density of 488.6 W kg[Formula: see text] at 2 A g[Formula: see text] in 6 mol L[Formula: see text] KOH aqueous solution using a symmetrical two-electrode system. The correlation between hierarchically porous structure with heteroatom doping and capacitive performance is also discussed.

Neutral Liquid Containing Chitosan and Polyol for Calcium Phosphate Cement

2018 ◽  
Vol 782 ◽  
pp. 9-14 ◽  
Author(s):  
Yoshiyuki Yokogawa ◽  
Kentaro Fujii ◽  
Ryota Izumiki ◽  
Seiya Shibata ◽  
Tasuku Takayasu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Acidic Solution ◽  
Chitosan Solution ◽  
Freeze Dried ◽  
Transparent Liquid ◽  
Chitosan Content ◽  
Work Of Fracture ◽  
Push Out

The self-hardening calcium phosphate cement (CPC) has widely been used in bone defect repairs. CPC tends to decay or disintegrate upon early contact with blood or body fluids, and the gelation of CPC paste using sodium alginate, chitosan, or collagen may overcome such a wash-out property. The incorporation of chitosan in CPC paste increased the compressive strength and work-of-fracture. However, the viscosity of CPC paste increased with an increase of chitosan content, and acidic liquid is not favorable, as chitosan must be dissolved in an acidic solution. The CPC paste using the liquid prepared from freeze-dried chitosan powder was easily push out from the syringe, but the content of chitosan was reduced. An addition of polyol-phosphate salt to chitosan solution produces a transparent liquid at physiological pH, and the chitosan content was found to be increased. Chitosan content of liquid was increased from 0.09% to 0.54 % by adding polyol to liquid, and the compressive strength of CPC was also increased.

Fabrication of Porous Structure of BCP Sintered Bodies Using Microwave Assisted Synthesized HAp Nano Powder

2007 ◽  
Vol 534-536 ◽  
pp. 49-52 ◽  
Author(s):  
Min Ho Youn ◽  
Rajat Kanti Paul ◽  
Ho Yeon Song ◽  
Byong Taek Lee
Keyword(s):  
Calcium Phosphate ◽  
Porous Structure ◽  
Relative Density ◽  
Polymethyl Methacrylate ◽  
Biphasic Calcium Phosphate ◽  
Sintering Temperature ◽  
Microwave Assisted ◽  
Nano Powder ◽  
Maximum Value ◽  
Porous Biphasic Calcium Phosphate

Using microwave synthesized HAp nano powder and polymethyl methacrylate (PMMA) as a pore-forming agent, the porous biphasic calcium phosphate (BCP) ceramics were fabricated depending on the sintering temperature. The synthesized HAp powders was about 70-90 nm in diameter. In the porous sintered bodies, the pores having 150-180 μm were homogeneously dispersed in the BCP matrix. Some amounts of pores interconnected due the necking of PMMA powders which will increase the osteoconductivity and ingrowth of bone-tissues while using as a bone substrate. As the sintering temperature increased, the relative density increased and showed the maximum value of 79.6%. From the SBF experiment, the maximum resorption of Ca2+ ion was observed in the sample sintered at 1000°C.

Effects of Additives on Pore Structures in Freeze Dried Calcium Phosphate Granules

2003 ◽  
Vol 240-242 ◽  
pp. 493-496 ◽  
Author(s):  
S.H. Oh ◽  
S.W. Kim ◽  
M.H. Ahn ◽  
Chang Kuk You ◽  
Hong In Shin ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Pore Structures ◽  
Freeze Dried

Study on the Preparation Technology of CuO Nanometric Powders by Homogeneous Precipitation in High Intensity Ultrasonic Field

2009 ◽  
Vol 79-82 ◽  
pp. 325-328
Author(s):  
Guang Li ◽  
Cheng Wen Chai
Keyword(s):  
High Intensity ◽  
Ultrasonic Field ◽  
Homogeneous Precipitation ◽  
Preparation Technology ◽  
Reaction Velocity ◽  
Ultrasound Field ◽  
Intensity Field ◽  
Speed Up ◽  
Partical Size ◽  
Xrd And Tem

Nanopowder CuO was prepared by a new method which involves homogeneous precipitation in high intensity field, and powder so obtained was examined by XRD and TEM. The mechanism and effects of conditions of treatment on process and final products are also discussed. These results indicate that not only the reaction velocity was speed up dramatically under ultrasound field but also the particle size of production was greatly affected by the intensity of ultrasound field, the greater the ultrasound field, the smaller the partical size.

Inhibition of phase transformation from β- to α-tricalcium phosphate with addition of poly (L-lactic acid) in selective laser sintering

2014 ◽  
Vol 20 (5) ◽  
pp. 369-376 ◽  
Author(s):  
Cijun Shuai ◽  
Jingyu Zhuang ◽  
Shuping Peng ◽  
Xuejun Wen
Keyword(s):  
Phase Transformation ◽  
Lactic Acid ◽  
Liquid Phase ◽  
Energy Density ◽  
Porous Structure ◽  
Laser Energy ◽  
Selective Laser Sintering ◽  
Transient Liquid Phase ◽  
Laser Energy Density ◽  
Content Type

Purpose – The paper aims to fabricate an α-tricalcium phosphate (TCP) scaffold with an interconnected porous structure via selective laser sintering (SLS). To inhibit the phase transformation from β- to α-TCP in fabrication process of porous scaffolds, a small amount (1 weight per cent) of poly (L-lactic acid) (PLLA) is added into β-TCP powder to introduce the transient liquid phase. Design/methodology/approach – The paper opted for the transient liquid phase of melting PLLA to decrease the sintering temperature in SLS. Meanwhile, the densification of β-TCP is enhanced with a combined effect of the capillary force caused by melting PLLA and the surface energy of β-TCP particles. Moreover, the PLLA will gradually decompose and completely disappear with laser irradiation. Findings – The testing results show the addition of PLLA enables the scaffolds to achieve a higher β-TCP content of 77 ± 1.49 weight per cent compared with the scaffold sintered from β-TCP powder (60 ± 1.65 weight per cent), when the laser energy density is 0.4 J/mm2. The paper provides the mechanism of PLLA inhibition on the phase transformation from β- to α-TCP. And the optimum sintering parameters are obtained based on experimental results, which are used to prepare a TCP scaffold with an interconnected porous structure via SLS. Research limitations/implications – This paper shows that the laser energy density is an important sintering parameter that can provide the means to control the micro-porous structure of the scaffold. If the laser energy density is too low, the densification is not enough. On the other hand, if the laser energy density is too high, the microcracks are observed which are attributed to the volume expansion during the phase transformation from β- to α-TCP. Therefore, the laser energy density must be optimized. Originality/value – The paper provides a feasible method for fabricating TCP artificial bone scaffold with good biological and mechanical properties.

scholarly journals Alveolar Ridge Preservation Using Xenogeneic Collagen Matrix and Bone Allograft

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Andreas O. Parashis ◽  
Charalampos J. Kalaitzakis ◽  
Dimitris N. Tatakis ◽  
Konstantinos Tosios
Keyword(s):  
Bone Allograft ◽  
Immunohistochemical Analysis ◽  
Collagen Matrix ◽  
Normal Mucosa ◽  
Ridge Preservation ◽  
Alveolar Ridge ◽  
Keratinized Tissue ◽  
Alveolar Ridge Preservation ◽  
Freeze Dried ◽  
Atraumatic Extraction

Alveolar ridge preservation (ARP) has been shown to prevent postextraction bone loss. The aim of this report is to highlight the clinical, radiographic, and histological outcomes following use of a bilayer xenogeneic collagen matrix (XCM) in combination with freeze-dried bone allograft (FDBA) for ARP. Nine patients were treated after extraction of 18 teeth. Following minimal flap elevation and atraumatic extraction, sockets were filled with FDBA. The XCM was adapted to cover the defect and 2-3 mm of adjacent bone and flaps were repositioned. Healing was uneventful in all cases, the XCM remained in place, and any matrix exposure was devoid of further complications. Exposed matrix portions were slowly vascularized and replaced by mature keratinized tissue within 2-3 months. Radiographic and clinical assessment indicated adequate volume of bone for implant placement, with all planned implants placed in acceptable positions. When fixed partial dentures were placed, restorations fulfilled aesthetic demands without requiring further augmentation procedures. Histological and immunohistochemical analysis from 9 sites (4 patients) indicated normal mucosa with complete incorporation of the matrix and absence of inflammatory response. The XCM + FDBA combination resulted in minimal complications and desirable soft and hard tissue therapeutic outcomes, suggesting the feasibility of this approach for ARP.

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