scholarly journals Preparation of Scaffolds of Amorphous Calcium Phosphate and Bacterial Cellulose for Use in Tissue Regeneration by Freeze-Drying Process

2020 ◽  
Vol 11 (1) ◽  
pp. 7357-7367
Keyword(s):  
Calcium Phosphate ◽  
Bacterial Cellulose ◽  
Tissue Regeneration ◽  
Amorphous Calcium Phosphate ◽  
Freeze Drying ◽  
Calcium Phosphates ◽  
Synthetic Polymers ◽  
Drying Process ◽  
Cytotoxicity Studies ◽  
The One

The elaboration of scaffolds for use in tissue regeneration processes plays an important role in the area of biomaterials. Natural and synthetic polymers, together with calcium phosphates, form suitable compounds for these studies because their combinations favor the union of the properties of both materials, such as their biocompatibility, biofunctionality, shape, porosity, and mechanical properties. The objective of this work was to develop a scaffold of amorphous calcium phosphate and bacterial cellulose, applying a freeze-drying process. The results demonstrated the feasibility of scaffolds elaboration applying the freeze-drying methodology. The formulation that presented the best results was the one that contained amorphous calcium phosphate (50%), bacterial cellulose gel (20%), and sodium alginate (30%). Cytotoxicity studies showed that the studied formulation did not present cytotoxicity, promoting cell viability.

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?

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).

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.

Effect on Drying Conditions on Amorphous Calcium Phosphate

2014 ◽  
Vol 631 ◽  
pp. 99-103 ◽  
Author(s):  
Agnese Brangule ◽  
Kārlis Gross
Keyword(s):  
Particle Size ◽  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Intermediate Phase ◽  
Calcium Phosphates ◽  
Ftir Spectra ◽  
The Body ◽  
Drying Methods ◽  
Dry Conditions ◽  
Drying Conditions

Amorphous calcium phosphate (ACP) plays an important role in the body and can be used as an intermediate phase for forming calcium phosphates. All ACPs are thermodynamically unstable compounds, unless stored in dry conditions or at low temperature (-18oC), and spontaneously undergo transformation to crystalline calcium phosphates (CaP). This work will investigate the influence of drying on the stability of ACP. ACPs powders were prepared by wet synthesis; mixing solution made of Ca (NO3)2∙4H2O and 30% ammonia with (NH4)2HPO4 and (NH4)2CO3 solution at room temperature. The suspension was stirred, filtered and washed several times with deionized water containing ammonia. ACP samples were dried at different conditions and with different drying agents (DA). XRD and FTIR spectra showed poorly crystallinity powders after drying. Some FTIR spectra indicated residual organic compounds from drying. The Rietveld’s method and Schrrer’s relationship estimated the particle size (0.5 – 20 nm) of ACP. Thermogravimetry (TG) revealed that the moisture (7% – 25%) is released upon drying, and the drying agents have no significant effect on. The drying methods are ordered to show which the most effective for removing moisture. By changing the drying conditions, it is a possible to obtain poorly crystalline ACPs with different particle size and moisture content.

scholarly journals Bone Tissue Regeneration by Collagen Scaffolds with Different Calcium Phosphate Coatings: Amorphous Calcium Phosphate and Low-Crystalline Apatite

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5860
Author(s):  
Syama Santhakumar ◽  
Ayako Oyane ◽  
Maki Nakamura ◽  
Yuto Yoshino ◽  
Mohammed Katib Alruwaili ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Calcium Phosphate ◽  
Bone Tissue ◽  
Tissue Regeneration ◽  
Amorphous Calcium Phosphate ◽  
Bone Tissue Regeneration ◽  
Apatite Coating ◽  
Low Crystalline ◽  
Mineralized Collagen

Surface-mineralized collagen sponges have attracted much attention as scaffolds for bone tissue engineering. Recently, we developed amorphous calcium phosphate (ACP) and low-crystalline apatite coating processes on collagen sponges. In the present study, we applied these coating processes to granular collagen sponges (referred to as Col) to compare the bone tissue regeneration capabilities of ACP-coated and apatite-coated Col (referred to as Col-ACP and Col-Ap, respectively) using a rat cranial bone defect model. According to micro-CT and histological analyses, Col-Ap enhanced bone tissue regeneration compared to Col, whereas Col-ACP did not. These results not only demonstrated the superior bone tissue regeneration capability of Col-Ap, but also indicated limitations of the in vitro simulated body fluid (SBF) test used in our previous study. Despite the apatite-forming ability of Col-ACP in SBF, it was ineffective in improving bone tissue regeneration in vivo, unlike Col-Ap, most likely due to the quick resorption of the ACP coating in the defect site. The present results clarified the importance of the coating stability in vivo and revealed that the low-crystalline apatite coating was more beneficial than the ACP coating in the fabrication of surface-mineralized collagen sponges for use as bone tissue engineering scaffolds.

scholarly journals An environmentally benign approach to achieving vectorial alignment and high microporosity in bacterial cellulose/chitosan scaffolds

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 13678-13688 ◽  
Author(s):  
Guohui Li ◽  
Avinav G. Nandgaonkar ◽  
Youssef Habibi ◽  
Wendy E. Krause ◽  
Qufu Wei ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Liquid Nitrogen ◽  
Freeze Drying ◽  
Environmentally Benign ◽  
Porous Scaffolds ◽  
Drying Process ◽  
Chitosan Scaffolds ◽  
Komagataeibacter Xylinus ◽  
Ice Templating

Bacterial cellulose (BC) nanofibers secreted by Komagataeibacter xylinus 10245 were applied alone or with chitosan to prepare highly aligned and porous scaffolds through a liquid nitrogen-initiated ice “templating” and freeze-drying process.

scholarly journals First successful stabilization of consolidated amorphous calcium phosphate (ACP) by cold sintering: toward highly-resorbable reactive bioceramics

2020 ◽  
Vol 8 (4) ◽  
pp. 629-635 ◽  
Author(s):  
Marina Luginina ◽  
Roberto Orru ◽  
Giacomo Cao ◽  
David Grossin ◽  
Fabien Brouillet ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Bioactive Compounds ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Ionic Composition ◽  
Bone Substitutes ◽  
Sintering Conditions

An adequate tuning of amorphous calcium phosphates ionic composition and cold sintering conditions allowed the first successful stabilization of these bioactive compounds. These results show promise for the setup of highly-resorbable bone substitutes.

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

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