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

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.

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.

scholarly journals Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Byung-Chul Jeong ◽  
Hyuck Choi ◽  
Sung-Woong Hur ◽  
Jung-Woo Kim ◽  
Sin-Hye Oh ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Bone Regeneration ◽  
Biphasic Calcium Phosphate ◽  
Cranial Bone ◽  
Specific Gene ◽  
Submicron Particle ◽  
Freeze Dried ◽  
Through Hole

Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as anin vitromodel and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluatingin vivoeffectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

scholarly journals Contemporary guided bone regeneration therapy for unaesthetic anterior peri-implantitis case

2016 ◽  
Vol 49 (4) ◽  
pp. 181
Author(s):  
Benso Sulijaya ◽  
Sandra Olivia Kuswandani ◽  
Yuniarti Soeroso
Keyword(s):  
Calcium Phosphate ◽  
Bone Regeneration ◽  
Dental Implant ◽  
Bone Substitutes ◽  
Initial Therapy ◽  
Guided Bone Regeneration ◽  
Collagen Membrane ◽  
Sandwich Technique ◽  
Bone Allografts ◽  
Freeze Dried

Background: Dental implant is one of an alternative solutions reconstruction therapy for missing teeth. Complication of dental implant could occurs and leading to implant failure. In order to restore the complication, surgical treatment with guided bone regeneration (GBR) is indicated. The potential use of bone substitutes is widely known to be able to regenerate the bone surrounding the implant and maintain bone volume. Purpose: The study aimed to demonstrate the effectiveness of implant-bone fully coverage by using sandwich technique of biphasic calcium phosphate (BCP) and demineralized freeze-dried bone allografts (DFDBA) bone substitutes combined with collagen resorbable membrane. Case: A 24-year-old male came with diagnosis of peri-implantitis on implant #11. Clinical finding indicated that implant thread was exposed on the labial aspect. Case management: After initial therapy including oral hygiene improvement performed, an operator did a contemporary GBR to correct the defect. Bone graft materials used were 40% β-tri calcium phosphate (β-TCP)-60% hydroxyapatite (HA) on the outer layer and DFDBA on the inner layer of the defect. Resorbable collagen membrane was used to cover the graft. Conclusion: GBR with sandwich technique could serve as one of the treatment choices for correcting an exposed anterior implant that would enhance the successful aesthetic outcome.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

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