scholarly journals Nanocomposites based on apatitic tricalcium phosphate and autofibrin

2021 ◽  
Vol 57 (4) ◽  
pp. 413-423
Author(s):  
I. E. Glazov ◽  
V. K. Krut’ko ◽  
R. A. Vlasov ◽  
O. N. Musskaya ◽  
A. I. Kulak
Keyword(s):  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Fibrin Clot ◽  
Combined Effect ◽  
Morphological Properties ◽  
Maturation Time ◽  
Soluble Calcium

Nanocomposites based on apatitic tricalcium phosphate in an autofibrin matrix were obtained by precipitation at a Ca/P ratio of 1.50, pH 9 and a maturation time from 30 min to 7–14 days. The resorbability of nanocomposites was determined by the composition of calcium phosphates, which, during long-term maturation, formed as the calcium-deficient hydroxyapatite with a Ca/P ratio of 1.66, whereas biopolymer matrix favored the formation of more soluble calcium phosphates with a Ca/P ratio of 1.53–1.59. It was found that the fibrin clot stabilized, along with apatitic tricalcium phosphate, the phase of amorphous calcium phosphate, which after 800 °C was transformed into resorbable α-tricalcium phosphate. Citrated plasma inhibited the conversion of apatitic tricalcium phosphate into stoichiometric hydroxyapatite, which also facilitated the formation of resorbable β-tricalcium phosphate after 800 °C. The combined effect of the maturation time and the biopolymer matrix determined the composition, physicochemical and morphological properties of nanocomposites and the possibililty to control its extent of resorption

scholarly journals Charge State of Silver Halide Colloids Determines the Antibacterial Activity in Amorphous Calcium Phosphate

2013 ◽  
Vol 587 ◽  
pp. 74-79 ◽  
Author(s):  
Kārlis Gross ◽  
Daina Kalnina ◽  
Zivile Stankeviciute ◽  
Vizma Nikolajeva
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Silver Iodide ◽  
Calcium Phosphates ◽  
Silver Halide ◽  
Antibacterial Action ◽  
X Ray Diffraction ◽  
Silver Halides ◽  
Diffraction Patterns

Removal of bacteria is important not only at implantation, but after long-term implant/prosthesis use. This requires strategies that employ different approaches for combating bacteria. Halides have the potential of an additional mechanism, and together with silver may provide a more powerful antibacterial strategy. Silver iodide was synthesized as colloids with a positive and negative charge and incorporated into an amorphous calcium phosphate (ACP) to provide a possible greater antibacterial action. Colloids were characterized by FTIR spectroscopy and the charge measured by zeta potential. Phase analysis by X-ray diffraction patterns confirmed the formation of b-AgI nanoparticles. Minimum inhibitory concentrations (MIC) for preventing the growth ofStaphylococcus aureusandPseudomonas aeruginosawere lower for ACP containing negatively charged silver halides. Amorphous calcium phosphates with silver iodide exhibited good inhibition capacity. Solubility was determined by the increase in pH and the release of silver after 48 hours. The minimum bactericidal concentration (MBC) was also determined. This work has shown the effect of AgI charge in amorphous calcium phosphate for providing antibacterial action.

Functionalized Calcium Phosphate-based Nanoparticles for the Treatment of Osteoporosis

2005 ◽  
Vol 873 ◽  
Author(s):  
Balasundaram G ◽  
Sato M ◽  
Webster TJ
Keyword(s):  
Calcium Phosphate ◽  
Bone Formation ◽  
Amorphous Calcium Phosphate ◽  
Bone Growth ◽  
Osteoporotic Bone ◽  
Amino Groups ◽  
Calcium Phosphate Nanoparticles ◽  
Bioactive Agents ◽  
Bone Growth Factor

AbstractIn an effort to decrease the number of problems associated with osteoporosis, the long-term goal of the present study is to design calcium phosphate-based nanoparticles that specifically attach to areas of low bone density and once attached, allow for the targeted release of bioactive agents that can quickly increase bone formation. Efforts are focused on nanoparticles of calcium phosphate-based materials since they are similar in size and chemistry to the major inorganic components of bone. As a first step in this research, the objective of the present study was to synthesize nanoparticles of crystalline hydroxyapatite (or HA) and amorphous calcium phosphate. Crystalline HA is stable under physiological fluids and, thus, will release embedded bioactive agents slowly. Alternatively, amorphous calcium phosphate is highly biodegradable and will, thus, release embedded bioactive agents quickly. A further objective of the present study was to functionalize such inorganic biodegradable materials with amino groups which would allow for the subsequent attachment of entities to direct such nanoparticles to osteoporotic bone and increased bone formation once attached. One promising approach to direct the nanoparticles to osteoporotic bone is to attach antibodies to pentosidine on the nanoparticles since pentosidine is present in higher amounts in osteoporotic compared to healthy bone. A promising approach to increase bone growth once nanoparticles attach to osteoporotic bone, is to embed nanoparticles with regions of the bone growth factor: bone morphogenic protein-2 (or BMP-2). Results of this study demonstrated the successful synthesis of both crystalline HA and amorphous calcium phosphate nanoparticles. Furthermore, results showed that these nanoparticles can be functionalized with versatile amino groups. In this manner, this study takes the first steps toward utilizing calcium phosphate based nanoparticles to reverse bone loss associated with osteoporosis.

Effect of Synthesis Temperature and Ca/P Ratios on Specific Surface Area of Amorphous Calcium Phosphate

2016 ◽  
Vol 721 ◽  
pp. 172-176 ◽  
Author(s):  
Jana Vecstaudza ◽  
Janis Locs
Keyword(s):  
Calcium Phosphate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Synthesis Temperature ◽  
Molar Ratios ◽  
Different Temperatures ◽  
Low Crystalline

Amorphous and low crystalline calcium phosphates are prospective candidates for bone implant manufacturing. Amorphous calcium phosphate (ACP) preparation technologies could be improved in terms of specific surface area (SSA) of obtained products. Current study is dedicated to the effect of synthesis temperature and Ca and P molar ratios (Ca/P) on SSA of ACP. Higher SSA can improve bioactivity of biomaterials. ACP was characterized by XRD, FT-IR, SEM and BET N2 adsorption techniques. Spherical nanoparticles (<45 nm in size) were obtained independently of initial Ca/P ratio and synthesis temperature. For the first time comparison of SSA was shown for ACP obtained at different temperatures (0 °C and 20 °C) and Ca/P molar ratios (1.5, 1.67 and 2.2).

Synthesis and Properties of α-Tricalcium Phosphate from Amorphous Calcium Phosphate as Component for Bone Cements

2016 ◽  
Vol 721 ◽  
pp. 182-186
Author(s):  
Zilgma Irbe ◽  
Dagnija Loca ◽  
Agnese Pura ◽  
Liga Berzina-Cimdina
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Calcium Phosphate ◽  
Bone Defect ◽  
Tricalcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Heat Treating ◽  
Bone Cements ◽  
Important Ingredient ◽  
Reactive Particles

α-Tricalcium phosphate is an important ingredient of calcium phosphate bone cements, which are used for bone defect augmentation and repair. In this study sub-micrometre sized α­tricalcium phosphate particles were synthesized by heat treating amorphous calcium phosphate. Size of synthesized particles depended on duration and temperature of heat treatment. Longer duration and higher temperatures produced larger particles. The reactivity of synthesized particles did not correlate with particle size – the smallest particles did not have the highest reactivity. The most reactive particles were prepared at 700-800 °C. The prepared particles were more reactive than those of conventionally synthesized α-tricalcium phosphate.

In Vitro Dissolution Behavior of Biphasic Tricalcium Phosphate Composite Powders Composed of α-Tricalcium Phosphate and β-Tricalcium Phosphate

2008 ◽  
Vol 368-372 ◽  
pp. 1206-1208 ◽  
Author(s):  
Yan Bao Li ◽  
Dong Xu Li ◽  
Wen Jian Weng
Keyword(s):  
Heat Treatment ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Ph Value ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
Buffer Solution ◽  
Composite Powders

Biphasic tricalcium phosphate (BTCP) powders composed of α-tricalcium phosphate (α-TCP) and β-tricalcium phosphate (β-TCP) were prepared using amorphous calcium phosphate (ACP) precursor after heat treatment at 800oC. The in vitro dissolution behavior of the powders was examined after soaked in 0.1M NaAc-HAc buffer solution for different times. It was revealed that the Ca2+ and PO4 3- concentration, and pH value of the BTCP-soaked solution are higher than those of the α-TCP- and β-TCP-soaked solutions. The dissolution behavior of BTCP powders was explained. The specific dissolution behavior of BTCP powders can widen the biodegradation range of calcium phosphate family.

scholarly journals Ultrasonic application and spray drying during amorphous calcium phosphate synthesis

2019 ◽  
Vol 8 (4) ◽  
pp. 711-714
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Calcium Phosphate ◽  
Spray Drying ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Calcium Content ◽  
Synthesis Process ◽  
Particle Sizes ◽  
Ultrasound Application

Hydroxyapatite, amorphous calcium phosphates, calcium triphosphate and calcium octaphosphate are the main components present in bones and teeth. Calcium phosphates are easily synthesized, playing an important role in regenerative medicine, being able to be used as bone implants. There are different ways of synthesizing phosphates, the most commonly used being wet chemical method. The objective of this work was to study the influence of the use of ultrasound and spray drying on the synthesis of amorphous calcium phosphate. Two synthetic variants were studied. One without ultrasound application and the other with ultrasound application. The samples obtained were characterized by X-ray diffraction, FTIR spectroscopy and scanning electron microscopy. The particle size by electron microscopy and the calcium content by atomic absorption was determined. The results showed that when spray drying is applied, particle sizes of less than 261 nm are obtained in the samples synthesized without ultrasound application, being less than 59 nm in the samples synthesized with ultrasound application. The statistical analysis by ANOVA showed significant differences between the particle sizes of the samples synthesized without ultrasound application and the samples synthesized by applying ultrasound. In both cases the particles were spherical. The results obtained show that the application of ultrasound during the synthesis process decreases the particle size, increasing the surface area, which favors the spray drying process.

Stability of Ultrathin Amorphous Calcium Phosphate Artificial Enamel Sheets under Simulated Intraoral Environment Condition

2019 ◽  
Vol 829 ◽  
pp. 16-20
Author(s):  
Nobuhiro Kato ◽  
Mizuki Hirai ◽  
Ei Yamamoto ◽  
Shigeki Hontsu
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Dental Materials ◽  
Cross Sectional ◽  
Sem Image ◽  
Long Term Stability ◽  
Optical Images ◽  
Surface Morphologies ◽  
Environment Condition

Dental materials purely composed of calcium phosphate are ideal for the dental medicine. We have been developing ultrathin amorphous calcium phosphate (ACP) sheets for enamel repair. In this study, long term stability of the ultrathin ACP sheets applied on enamel surfaces which kept in a simulated intraoral condition for 21 days was evaluated. Surface morphologies of the ACP sheets were observed by optical images. A boundary condition between the ACP sheet and the enamel was evaluated by cross-sectional SEM image. A durability of the ACP sheet was evaluated by a brushing test conducted after 21 days incubation. As the result of these evaluations, it was confirmed that the ACP sheets were stable even after long-term incubation under the simulated intraoral environment condition.

PREPARATION AND MORPHOLOGY OF POROUS NANOCALCIUM PHOSPHATE/POLY(L-LACTIC ACID) COMPOSITES

2005 ◽  
Vol 04 (04) ◽  
pp. 517-523
Author(s):  
WENJIAN WENG ◽  
YANBO GAO ◽  
LILI PAN ◽  
YANBAO LI ◽  
PIYI DU ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Materials Science ◽  
Calcium Phosphates ◽  
Point Of View ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Highly Porous

Biodegradable porous materials can serve as a scaffold in tissue engineering. In this work, highly porous nano-calcium phosphate (NCP)/poly(L-lactic acid)(PLLA) composites were prepared by a thermally induced phase separation technique. Five calcium phosphates with different biodegradation rate were selected, i.e. amorphous calcium phosphate, α-tricalcium phosphate, β-tricalcium phosphate and biphasic α/β-tricalcium phosphate. The results showed that the NCP particles could be homogenously incorporated into pore walls; the composites had a porosity of ~90%, and a pore size of ~200 μm. From the point of view of materials science, the obtained porous NCP/PLLA composites demonstrate to have a capability of applying in bone tissue engineering.

Thermokinetic Investigation of the Drying Conditions on Amorphous Calcium Phosphate

2017 ◽  
Vol 758 ◽  
pp. 204-209
Author(s):  
Agnese Brangule ◽  
Līga Avotiņa ◽  
Artūrs Zariņš ◽  
Mihails Haļitovs ◽  
Kārlis Agris Gross ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Crystalline Structure ◽  
Amorphous Calcium Phosphate ◽  
Freeze Drying ◽  
Calcium Phosphates ◽  
Drying Condition ◽  
Drying Conditions

The present work investigated dried calcium phosphate powders which still retain an amorphous or poorly crystalline structure under a variety of conditions. In previous studies, freeze-drying was found to be the optimum drying condition. However, several publications, as well as our previous studies, have shown that calcium phosphate amorphous, or a poorly crystalline structure, can retain their structure even if the samples are dried immediately after synthesis up to 200°C. In our study, we used the thermokinetic studies FTIR and XRD and showed that the samples are amorphous, or poorly crystalline, but were unable to answer the questions: Is there a difference between the differently dried amorphous calcium phosphates? What are the optimum drying conditions under which the amorphous calcium phosphate (ACP) structure loses the physically bounded water, but still retains the chemically bounded water?

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