The present method describes the procedure to fabricate calcium phosphate foams with suitable open porosity, pore size, and composition to perform three-dimensional (3D) cell cultures with the objective to simulate the bone tissue microenvironment in vitro. Foams with two compositions but equivalent porosity can be fabricated. On the one hand, hydroxyapatite foams obtained by hydrolysis at 37 °C, with microstructure that mimics the small crystal size of the mineral component of bones, and on the other hand, beta tricalcium phosphate foams with polygonal grains obtained by sintering at 1100 °C. In the first part of the chapter the calcium phosphate foams are briefly described. Afterwards, the foaming process is described in detail, including alternatives to overcome processing problems than can arise. Finally, insights are provided on how to perform 3D cell cultures using the calcium phosphate foams as substrates.

• Klíčová slova
• Bone model, Calcium phosphate foam, Cell culture, Hydroxyapatite, Osteoblast, Scaffold, Three-dimensional, Tissue engineering, Tricalcium phosphate,
• MeSH
• biologické modely * MeSH
• buněčné kultury MeSH
• buněčné mikroprostředí MeSH
• fosforečnany vápenaté chemie   MeSH
• kosti a kostní tkáň cytologie   MeSH
• krysa rodu Rattus MeSH
• poréznost MeSH
• testování materiálů MeSH
• tkáňové inženýrství metody   MeSH
• tkáňové podpůrné struktury chemie   MeSH
• velikost částic MeSH
• vyrobené materiály MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosforečnany vápenaté MeSH

Composite materials based on a polyamide fabric (aramid) and a polydymethylsiloxane (PDMS) matrix were designed for application in bone surgery. In order to increase the bioactivity, 2, 5, 10, 15, 20, and 25 vol.% of nano/micro hydroxyapatite (HA) and tricalcium phosphate (TCP) were added. We studied the effect of the additives on the biocompatibility of the composite. It appears that nano additives have a more favorable effect on mechanical properties than microparticles. 15 vol.% of nano hydroxyapatite additive is an optimum amount for final application of the composites as substitutes for bone tissue: in this case both the mechanical properties and the biological properties are optimized without distinct changes in the inner structure of the composite.

• MeSH
• apatity MeSH
• dimethylpolysiloxany * MeSH
• fosforečnany vápenaté * MeSH
• hydroxyapatit * MeSH
• kosti a kostní tkáň chirurgie   MeSH
• kostní náhrady chemie   normy   MeSH
• králíci MeSH
• krevní plazma MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• mikrotechnologie MeSH
• nanostruktury MeSH
• nylony * MeSH
• osteointegrace fyziologie   MeSH
• polymery * MeSH
• povrchové vlastnosti MeSH
• pružnost MeSH
• software MeSH
• testování materiálů metody   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• apatity MeSH
• dimethylpolysiloxany * MeSH
• fosforečnany vápenaté * MeSH
• hydroxyapatit * MeSH
• Kevlar Aramid fibers MeSH Prohlížeč
• kostní náhrady MeSH
• nylony * MeSH
• poly(dimethylsiloxane)-polyamide copolymer MeSH Prohlížeč
• polymery * MeSH
• tricalcium phosphate MeSH Prohlížeč

UNLABELLED: Direct ink writing (DIW) techniques open up new possibilities for the fabrication of patient-specific bone grafts. Self-setting calcium phosphate inks, which harden at low temperature, allow obtaining nanostructured scaffolds with biomimetic properties and enhanced bioactivity. However, the slow hardening kinetics hampers the translation to the clinics. Different hydrothermal treatments for the consolidation of DIW scaffolds fabricated with an α-tricalcium phosphate /pluronic F127 ink were explored, comparing them with a biomimetic treatment. Three different scaffold architectures were analysed. The hardening process, associated to the conversion of α-tricalcium phosphate to hydroxyapatite was drastically accelerated by the hydrothermal treatments, reducing the time for complete reaction from 7 days to 30 minutes, while preserving the scaffold architectural integrity and retaining the nanostructured features. β-tricalcium phosphate was formed as a secondary phase, and a change of morphology from plate-like to needle-like crystals in the hydroxyapatite phase was observed. The binder was largely released during the treatment. The hydrothermal treatment resulted in a 30% reduction of the compressive strength, associated to the residual presence of β-tricalcium phosphate. Biomimetic and hydrothermally treated scaffolds supported the adhesion and proliferation of rat mesenchymal stem cells, indicating a good suitability for bone tissue engineering applications. STATEMENT OF SIGNIFICANCE: 3D plotting has opened up new perspectives in the bone regeneration field allowing the customisation of synthetic bone grafts able to fit patient-specific bone defects. Moreover, this technique allows the control of the scaffolds' architecture and porosity. The present work introduces a new method to harden biomimetic hydroxyapatite 3D-plotted scaffolds which avoids high-temperature sintering. It has two main advantages: i) it is fast and simple, reducing the whole fabrication process from the several days required for the biomimetic processing to a few hours; and ii) it retains the nanostructured character of biomimetic hydroxyapatite and allows controlling the porosity from the nano- to the macroscale. Moreover, the good in vitro cytocompatibility results support its suitability for cell-based bone regeneration therapies.

• Klíčová slova
• 3D plotting, Biomimetic, Bone graft, Bone regeneration, Calcium phosphate, Direct ink writing, Hydroxyapatite,
• MeSH
• buněčná adheze MeSH
• fosforečnany vápenaté chemie   MeSH
• inkoust * MeSH
• krysa rodu Rattus MeSH
• mezenchymální kmenové buňky cytologie   metabolismus   MeSH
• nanostruktury chemie   MeSH
• pevnost v tlaku MeSH
• polyethyleny chemie   MeSH
• polypropyleny chemie   MeSH
• potkani inbrední LEW MeSH
• tkáňové podpůrné struktury chemie   MeSH
• vysoká teplota MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alpha-tricalcium phosphate MeSH Prohlížeč
• fosforečnany vápenaté MeSH
• polyethyleny MeSH
• polypropyleny MeSH
• UCON 50-HB-5100 MeSH Prohlížeč

• MeSH
• biokompatibilní materiály * MeSH
• biomechanika MeSH
• fosforečnany vápenaté * MeSH
• hydroxyapatity MeSH
• keramika * MeSH
• lidé MeSH
• protézy a implantáty * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• alpha-tricalcium phosphate MeSH Prohlížeč
• biokompatibilní materiály * MeSH
• calcium phosphate, dibasic, anhydrous MeSH Prohlížeč
• calcium phosphate, monobasic, anhydrous MeSH Prohlížeč
• calcium phosphate MeSH Prohlížeč
• fosforečnany vápenaté * MeSH
• hydroxyapatity MeSH
• tetracalcium phosphate MeSH Prohlížeč

Streptococcus mutans is one of the bacteria that initiates the colonization of the pellicle at the tooth surface. It forms a plaque, together with other bacteria, which gradually dissolves the pellicle and leaves the tooth surface unprotected against the acidic oral environment. Calcium phosphate ceramics are excellent synthetic materials for the study of biofilm formation in dentistry because they are comparable to teeth in chemical composition and structure. Calcium phosphates can be processed to achieve a variety of crystalline compounds with biologically relevant ionic substitutions and structures that allow study of the effect of the surface chemistry and the topography independently. In this article, we describe the preparation and characterization of three types of calcium phosphate-based materials as a suitable surface for the formation of the S. mutans biofilm: beta-tricalcium phosphate (β-TCP); sintered hydroxyapatite (SHA); and calcium-deficient hydroxyapatite (CDHA). The densest biofilms were formed on the surfaces of SHA and CDHA, with no significant differences due to the stoichiometry or microstructure. In contrast, β-TCP showed a lower susceptibility to S. mutans biofilm formation, suggesting that the crystalline structure is the controlling parameter. Subsequently, SHA was selected to develop a dental biofilm model that allowed study of S. mutans biofilm susceptibility to chlorhexidine and ethanol.

• Klíčová slova
• Bacteria, Biofilm, Calcium phosphate, Oral biofilm model, Streptococcus mutans,
• MeSH
• biofilmy MeSH
• fosforečnany vápenaté * farmakologie   MeSH
• hydroxyapatit chemie   MeSH
• keramika farmakologie   MeSH
• Streptococcus mutans * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• calcium phosphate MeSH Prohlížeč
• fosforečnany vápenaté * MeSH
• hydroxyapatit MeSH

PURPOSE OF THE STUDY: The aim of the experimental study is to find out how fibrin influences the speed of osteiontegration of bioactive glass-ceramic materials BAS-O, BAS-HA, BAS-R (LASAK Prague, Czech Republic) and how it influences the response of live tissue at the implant-bone interface in the interval of 1-8 weeks. MATERIAL: Dense materials BAS-0 (glass-ceramics), BAS-HA (hydroxyapatite) and BAS-R (beta tricalcium phosphate) in the form of 0.6-1 mm granules were implanted in artificially created defects in tibia of an experimental animal with the addition of 0.1 ml of fibrin adhesive system Beriplast. Control implantation was performed with the addition of physiological solution. Materials BAS-HA and BAS-R were implanted in the same way in the ratio of 7:3, 8:2 and 9:1. Duration of exposure was 1-8 weeks. Radiographs of samples were taken by Mammograph and decalcified sections were coloured by toluidine blue and examined at 60 times and 120 times magnification. RESULTS: Surgical wounds were healed per primam. Radiographs of materials with the fibrin system showed clearly after one week defects and implants, after the third week part of the materials penetrated above the bone surface, after the fourth week there were evident signs of bone tissue formation between particles of BAS-HA, BAS-R and their mixtures. The most marked bone formation took place in the seventh and eighth weeks. With the use of glass-ceramics without fibrin the particles were after three weeks less clear, after the fourth week BAS-HA and BAS-R penetrated above the surface. A significant bone formation was obvious after the sixth and seventh weeks. There were no signs of resorption or fibrous encapsulating. Microscopic examination proved enveloping of particles of BAS-0 by fibrous tissue which was evident partially also after the eight week. With the use of fibrin the situation was analogical. In BAS-HA and BAS-R the finding in the first week was similar. With fibrin, there was after the third week a mature lamellar bone in the vicinity of granules and the fibrous interlayer disappeared. Neither positive nor negative impact of fibrin on the process of healing was found. With the application of BAS-R and fibrin system the bone tissue was after the third week more significant and trabeculae more bulky. The final result after eight weeks was the same: Ingrowth of the mixtures of the given materials proceeded in the same way. DISCUSSION: The applied glass-ceramic materials are used in the clinical practice. The speed of osteointegration depends on the quality of the bone bed, and on the tolerance of these materials by live tissue. Osteintegration can be accelerated by the use of growth factors or stem cells cultivated in the tissue culture. Fibrin which creates a network along which osteoblasts can migrate should have a similar quality. It seems that of decisive importance is the thickness of the fibrin layer around the implants. If this layer is thick glass-ceramics is enveloped more probably to fibrous tissue. In a thin layer the process is accelerated within the first three weeks. After a longer exposure the differences are not evident. Samples of BAS-HA and BAS-R, both applied separately and in a mixture, showed a marked bioactivity in the experiment. During eight weeks no signs were found of resorption which is typical of tricalcium phosphate in a longer time interval. CONCLUSION: In the experiment on an animal the fibrin adhesive system accelerated osteointegration of bioactive materials BAS-HA, BAS-R and their mixtures until the third week after the implantation. Small differences with the use of fibrin were adjusted within six weeks. Materials BAS-HA, BAS-R and their mixtures were completely osteointegrated. Glass-ceramics BAS-0 was partially enveloped by fibrous tissue, even with the use of fibrin adhesive system. During eight weeks no resorption of materials was found. The process of ingrowth can be seen on radiographs. X-ray picture of bone formation in BAS-HA, BAS-R correlates with the histological finding. The fibrin adhesive system facilitates manipulation with fine granules.

• MeSH
• biokompatibilní materiály * MeSH
• experimentální implantáty MeSH
• fibrin farmakologie   MeSH
• fosforečnany vápenaté MeSH
• hydroxyapatit MeSH
• keramika * MeSH
• osteointegrace účinky léků   MeSH
• psi MeSH
• radiografie MeSH
• tibie diagnostické zobrazování   patologie   chirurgie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-tricalcium phosphate MeSH Prohlížeč
• biokompatibilní materiály * MeSH
• fibrin MeSH
• fosforečnany vápenaté MeSH
• Glass ceramics MeSH Prohlížeč
• hydroxyapatit MeSH
• tricalcium phosphate MeSH Prohlížeč

Due to unique osteogenic properties, tricalcium phosphate (TCP) has gained relevance in the field of bone repair. The development of novel and rapid sintering routes is of particular interest since TCP undergoes to high-temperature phase transitions and is widely employed in osteoconductive coatings on thermally-sensitive metal substrates. In the present work, TCP bioceramics was innovatively obtained by Ultrafast High-temperature Sintering (UHS). Ca-deficient hydroxyapatite nano-powder produced by mechanochemical synthesis of mussel shell-derived calcium carbonate was used to prepare the green samples by uniaxial pressing. These were introduced within a graphite felt which was rapidly heated by an electrical current flow, reaching heating rates exceeding 1200 °C min-1. Dense (> 93%) ceramics were manufactured in less than 3 min using currents between 25 and 30 A. Both β and α-TCP were detected in the sintered components with proportions depending on the applied current. Preliminary tests confirmed that the artifacts do not possess cytotoxic effects and possess mechanical properties similar to conventionally sintered materials. The overall results prove the applicability of UHS to bioceramics paving the way to new rapid processing routes for biomedical components.

• Klíčová slova
• Bioceramics, Mechanochemical synthesis, TCP, UHS, Ultra-high temperature sintering,
• MeSH
• biokompatibilní materiály * MeSH
• fosforečnany vápenaté * MeSH
• keramika MeSH
• teplota MeSH
• testování materiálů MeSH
• vysoká teplota MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní materiály * MeSH
• fosforečnany vápenaté * MeSH
• tricalcium phosphate MeSH Prohlížeč

The structure degradation and strength changes of calcium phosphate scaffolds after long-term exposure to an acidic environment simulating the osteoclastic activity were determined and compared. Sintered calcium phosphate scaffolds with different phase structures were prepared with a similar cellular pore structure and an open porosity of over 80%. Due to microstructural features the biphasic calcium phosphate (BCP) scaffolds had a higher compressive strength of 1.7 MPa compared with the hydroxyapatite (HA) and β-tricalcium phosphate (TCP) scaffolds, which exhibited a similar strength of 1.2 MPa. After exposure to an acidic buffer solution of pH = 5.5, the strength of the HA scaffolds did not change over 14 days. On the other hand, the strength of the TCP scaffolds decreased steeply in the first 2 days and reached a negligible value of 0.09 MPa after 14 days. The strength of the BCP scaffolds showed a steady decrease with a reasonable value of 0.5 MPa after 14 days. The mass loss, phase composition and microstructural changes of the scaffolds during degradation in the acidic environment were investigated and a mechanism of scaffold degradation was proposed. The BCP scaffold showed the best cell response in the in vitro tests. The BCP scaffold structure with the highly soluble phase (α-TCP) embedded in a less soluble matrix (β-TCP/HA) exhibited a controllable degradation with a suitable strength stability and with beneficial biological behavior it represented the preferred calcium phosphate structure for a resorbable bone scaffold.

• Klíčová slova
• Calcium phosphate, Cell response, Compressive strength, Degradation, Phase composition, Scaffold,
• MeSH
• buněčná adheze MeSH
• DNA metabolismus   MeSH
• fosforečnany vápenaté chemie   MeSH
• keramika chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kosti a kostní tkáň fyziologie   MeSH
• lidé MeSH
• mezenchymální kmenové buňky cytologie   MeSH
• pevnost v tlaku MeSH
• poréznost MeSH
• tkáňové podpůrné struktury chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA MeSH
• fosforečnany vápenaté MeSH

This work focuses on the analysis of structural and functional properties of calcium phosphate (CaP) incorporated bacterial cellulose (BC)-polyvinylpyrrolidone (PVP) based hydrogel scaffolds referred to as "CaP/BC-PVP". CaP is incorporated in the scaffolds in the form of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) in different concentrations (β-TCP: HA (w/w) = 20:80, 40:60, and 50:50). The scaffolds were characterized on the basis of porosity, thermal, biodegradation, mechanical, and cell viability/cytocompatibility properties. The structural properties of all the hydrogel scaffolds show significant porosity. The biodegradation of "CaP/BC-PVP" scaffold was evaluated following hydrolytic degradation. Weight loss profile, pH change, scanning electron microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) study confirm the significant degradability of the scaffolds. It is observed that a 50:50_CaP/BC-PVP scaffold has the highest degree of degradation. On the other hand, the compressive strengths of CaP/BC-PVP hydrogel scaffolds are found between 0.21 to 0.31 MPa, which is comparable with the human trabecular bone. The cell viability study is performed with a human osteosarcoma Saos-2 cell line, where significant cell viability is observed in all the hydrogel scaffolds. This indicated their ability to facilitate cell growth and cell proliferation. Considering all these substantial properties, CaP/BC-PVP hydrogel scaffolds can be suggested for detailed investigation in the context of bone regeneration application.

• Klíčová slova
• bacterial cellulose, bone regeneration, calcium phosphate, degradation, hydrogel scaffolds, mechanical property,
• Publikační typ
• časopisecké články MeSH

The current limitations of calcium phosphate cements (CPCs) used in the field of bone regeneration consist of their brittleness, low injectability, disintegration in body fluids and low biodegradability. Moreover, no method is currently available to measure the setting time of CPCs in correlation with the evolution of the setting reaction. The study proposes that it is possible to improve and tune the properties of CPCs via the addition of a thermosensitive, biodegradable, thixotropic copolymer based on poly(lactic acid), poly(glycolic acid) and poly(ethylene glycol) (PLGA⁻PEG⁻PLGA) which undergoes gelation under physiological conditions. The setting times of alpha-tricalcium phosphate (α-TCP) mixed with aqueous solutions of PLGA⁻PEG⁻PLGA determined by means of time-sweep curves revealed a lag phase during the dissolution of the α-TCP particles. The magnitude of the storage modulus at lag phase depends on the liquid to powder ratio, the copolymer concentration and temperature. A sharp increase in the storage modulus was observed at the time of the precipitation of calcium deficient hydroxyapatite (CDHA) crystals, representing the loss of paste workability. The PLGA⁻PEG⁻PLGA copolymer demonstrates the desired pseudoplastic rheological behaviour with a small decrease in shear stress and the rapid recovery of the viscous state once the shear is removed, thus preventing CPC phase separation and providing good cohesion. Preliminary cytocompatibility tests performed on human mesenchymal stem cells proved the suitability of the novel copolymer/α-TCP for the purposes of mini-invasive surgery.

• Klíčová slova
• biocompatibility, injectable bone cements, kinetics, morphology, rheology, thixotropic,
• MeSH
• biokompatibilní materiály chemie   MeSH
• fosforečnany vápenaté chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kostní cementy chemie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• mechanické jevy MeSH
• molekulární struktura MeSH
• polyestery chemie   MeSH
• polyethylenglykoly chemická syntéza   chemie   MeSH
• polyglactin 910 chemická syntéza   chemie   MeSH
• polymerizace MeSH
• reologie MeSH
• testování materiálů MeSH
• viabilita buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• fosforečnany vápenaté MeSH
• kostní cementy MeSH
• poly(lactic-glycolic acid)-poly(ethyleneglycol) copolymer MeSH Prohlížeč
• polyestery MeSH
• polyethylene glycol-poly(lactide-co-glycolide) MeSH Prohlížeč
• polyethylenglykoly MeSH
• polyglactin 910 MeSH
• tricalcium phosphate MeSH Prohlížeč