H. Meissner

Technische Universität Dresden, Dresden, Saxony, Germany

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Publications (23)27.69 Total impact

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    ABSTRACT: Morphometry of the lamina reticularis of the guinea pig cochlea was performed using scanning electron microscopy. Seventy-four geometrical parameters of the lamina reticularis, the bundles of stereocilia, and individual stereocilia, in all rows of hair cells and within the individual hair cells, were measured at ten equally spaced locations along the longitudinal direction of the cochlea. Variations of the parameters versus the longitudinal coordinate were statistically analyzed and fitted with polynomials (constant, linear, or quadratic). Our data show that a unique set of geometrical parameters of inner and outer hair cells is typical for every frequency-dependent position at the lamina reticularis. Morphology of the outer hair cell structures varies more than respective parameters of the inner hair cells. Mechanical modeling using the obtained geometrical parameters provides a novel glance at the mechanical characteristics with respect to the cochlear tonotopy.
    Journal of the Association for Research in Otolaryngology 10/2013; · 2.95 Impact Factor
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    ABSTRACT: Chitin is a biopolymer found in cell walls of various fungi and skeletal structures of numerous invertebrates. The occurrence of chitin within calcium- and silica-containing biominerals has inspired development of chitin-based hybrids and composites in vitro with specific physico-chemical and material properties. We show here for the first time that the two-dimensional α-chitin scaffolds isolated from the skeletons of marine demosponge Ianthella basta can be effectively silicified by the two-step method with the use of Stöber silica micro- and nanodispersions under Extreme Biomimetic conditions. The chitin-silica composites obtained at 120°C were characterized by the presence of spherical SiO2 particles homogeneously distributed over the chitin fibers, which probably follows from the compatibility of Si-OH groups to the hydroxyl groups of chitin. The biocomposites obtained were characterized by various analytical techniques such as energy dispersive spectrometry, scanning electron microscopy, thermogravimetric/differential thermal analyses as well as X-ray photoelectron spectroscopy, Fourier transform infrared and Raman spectroscopy to determine possible interactions between silica and chitin molecule. The results presented proved that the character and course of the in vitro chitin silicification in Stöber dispersions depended considerably on the degree of hydrolysis of the SiO2 precursor.
    Materials science & engineering. C, Materials for biological applications. 10/2013; 33(7):3935-41.
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    ABSTRACT: Mandibular tumor resection can lead to a mandibular segmental defect. LaserCUSING® is used to produce a mandibular implant, designed to be identical to the shape of the mandibular defect. Novel microrough surfaces result from this generative technology. In the current study, the behavior of human osteoblasts on untreated laser-cused titanium specimens or on specimens conditioned with different blasting agents was analyzed. The conditioning of these specimens resulted in surfaces with graded roughness. White light confocal microscopy and single-cell force spectroscopy were used to characterize the surface of the specimens and to quantify the initial adhesion of primary human osteoblasts to the specimens respectively. Furthermore, cell growth, viability, apoptosis as well as mineralization of the specimens were analyzed over a time-period of 2 months. Compared to specimens that were treated with blasting agents, untreated specimens had the highest surface roughness. Quantitative SCFS measurements demonstrated that the adhesion of human primary osteoblasts was the highest on these specimens. Additionally, the untreated specimens allowed the highest number of osteoblasts to colonize. Mineralization studies showed increasing calcium and phosphor elemental composition for all specimen series. It can be concluded that untreated laser-cused titanium specimens are superior to promote the initial adhesion und subsequent colonization by osteoblast cells.
    Journal of Biomedical Materials Research Part A 06/2013; · 2.83 Impact Factor
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    ABSTRACT: Background: The study describes the development and implementation of a digital nose database in order to provide patients with nasal prostheses following rhinectomy. Mirrored data for computer-aided design (CAD) cannot be used due to the unpaired structure of the nose. Materials and Methods: The faces of 202 people were digitized using a 3-dimension (3D) scanner. The noses were scaled, measured and classified according to objective criteria. The physician, the patient and the anaplastologist can collaborate in order to select an appropriate nose from the multitude of existing nose types and sizes. Virtual 'fittings' and an individual adaptation of the nose are feasible. For this purpose the epiTecture software was applied. The selected nose is then created on a 3D printer as a thermopolymer model. This model can be fitted and corrected as a physical model on the patient. The remaining steps are identical to conventional prosthesis production. Results: A digital nose database was developed at the University Hospital Dresden with the help of the epiTecture software. Instructions for usage are illustrated using the example of a patient. Conclusions: The process of providing nasal prostheses described in this paper is different from conventional processes. This is primarily due to the elimination of physical modeling, causing substantially less strain for the patient.
    Onkologie 01/2013; 36(1-2):7-11. · 1.00 Impact Factor
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    ABSTRACT: Purpose: Application of function-restoring individual implants for the bridging of defects in mandibles with continuity separation requires a stable fixation with special use of the cortical bone stumps. Materials and Methods: Five section planes each of 100 computed tomographies of poly-traumatized patients' jaws were used for measuring the thickness of the cortical layer and the bone density of the mandible. The CT scans of 28 female and 72 male candidates aged between 12 and 86 years with different dentition of the mandible were available. Results: The computed tomographic evaluations of human mandibles regarding the layer thickness of the cortical bone showed that the edge of the mandible in the area of the horizontal branch possesses the biggest layer thickness of the whole of the lower jaws. The highest medians of the cortical bone layer thickness were found in the area of the molars and premolars at the lower edge of the lower jaws in 6-o'clock position, in the area of the molars in the vestibular cranial 10-o'clock position and in the chin region lingual-caudal in the 4-o'clock position. The measurement of the bone density showed the highest values in the 8-o'clock position (vestibular-caudal) in the molar region in both males and females. Conclusion: The average values available of the bone density and the layer thickness of the cortical bone in the various regions of the lower jaw, taking into consideration age, gender and dentition, are an important aid in practice for determining a safe fixation point for implants in the area of the surface layer of the mandible by means of screws or similar fixation elements.
    RöFo - Fortschritte auf dem Gebiet der R 10/2012; · 2.76 Impact Factor
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    ABSTRACT: Unique skeletal formations of marine invertebrates, including representatives of Echinodermata, have the unique potential to serve as templates for bio-inspired materials chemistry, biomimetics, and materials science. The sand dollar Scaphechinus mirabilis (Agassiz, 1983) is widely distributed in the northwest of the Pacific Ocean from southern Japan to the Aleutian Islands. This animal is the main source of naphtochinone-based substances. These compounds have recently drawn medical attention for their use as cardiological and ophthalmological drugs. Unfortunately, after extraction of the naphtochinones, the residual skeletons and spines of the sand dollars were usually discarded. Here, we report the first method for the preparation of nanostructurally organized spines of S. mirabilis, using a simple enzymatic and hydrogen peroxide-based treatment. Application of this method opens the way for development of non-wasteful environmentally clean technology of sand dollars as well-known industrial marine invertebrates.
    Marine Biotechnology 06/2011; 13(3):402-10. · 3.15 Impact Factor
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    ABSTRACT: To assess the stability of osteosynthesis in diacapitular condylar fractures we compared fixation using ultrasound-aided resorbable pins with poly-(D,L)-lactide (SonicWeld® Rx, KLS Martin, Tuttlingen, Germany) with that of titanium screws in 20 pig mandibles, 10 in each group. Isolated diacapitular fractures were created using a surgical chisel. Ten fractures were each repositioned and fixed by two pins (17 and 11 mm long, 2.1mm in diameter), and 10 fractures were fixed by two titanium screws of equal length, 2.0mm in diameter. Shear tests were done immediately after treatment to measure the maximum force to disrupt the fixation. Fixation with pins resisted mean shear forces of 310N until the pins fractured, whereas fixation with titanium screws failed at 918N when the screws pulled out of the bone. Long-term stability and resorption of pins will have to be analysed in an in vivo study.
    British Journal of Oral and Maxillofacial Surgery 06/2011; 49(4):297-301. · 2.72 Impact Factor
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    ABSTRACT: The skeletal structures of Echinodermata have the intriguing biomimetic potential to serve as templates for bio-inspired materials chemistry, architecture and materials science. Up to now, sea urchin skeletons have been the most intensively investigated, due to peculiarities of their biomineralization-related processes and the material properties of their calcified teeth, tests and spines. In contrast to sea urchins, the underlying microstructure and chemistry of the highly perforated spines of sand dollars, especially Scaphechinus mirabilis (Agassiz 1863), have not been subject to much previous investigations. This sand dollar is widely distributed in the northwest of the Pacific Ocean from southern Japan to the Aleutian Islands and is known as the main source of naphtoquinone-based substances, which have recently drawn medical attention for their use as cardiological and ophthalmological drugs. Here we report the first study for the sequential preparation of nanostructurally organized spines of S. mirabilis, using a simple enzymatic and hydrogen peroxide-based treatment. The cleaned spines were investigated by using different bioanalytical (AAS, FTIR, Raman and NEXAFS spectroscopy) and structural (XRD) methods to identify the structural nature and origin of the spine-based biomineral. SEM investigations were employed to better understand the structural peculiarities of the inner organization of the spines on micro- and nanolevels. The possible role of low magnesium calcite detected in S. mirabilis spines is discussed.
    Journal of Advanced Microscopy Research. 08/2010; 5:1-10.
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    ABSTRACT: Marine invertebrate organisms including sponges (Porifera) not only provide an abundant source of biologically active secondary metabolites but also inspire investigations to develop biomimetic composites, scaffolds and templates for practical use in materials science, biomedicine and tissue engineering. Here, we presented a detailed study of the structural and physico-chemical properties of three-dimensional skeletal scaffolds of the marine sponges Aiolochroia crassa, Aplysina aerophoba, A. cauliformis, A. cavernicola, and A. fulva (Verongida: Demospongiae). We show that these fibrous scaffolds have a multilayered design and are made of chitin. (13)C solid-state NMR spectroscopy, NEXAFS, and IR spectroscopy as well as chitinase digestion and test were applied in order to unequivocally prove the existence of alpha-chitin in all investigated species.
    International journal of biological macromolecules 08/2010; 47(2):132-40. · 2.37 Impact Factor
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    ABSTRACT: In order to evaluate the biomedical potential of three-dimensional chitinous scaffolds of poriferan origin, chondrocyte culturing experiments were performed. It was shown for the first time that freshly isolated chondrocytes attached well to the chitin scaffold and synthesized an extracellular matrix similar to that found in other cartilage tissue engineering constructs. Chitin scaffolds also supported deposition of a proteoglycan-rich extracellular matrix of chondrocytes seeded bioconstructs in an in vivo environment. We suggest that chitin sponge scaffolds, apart from the demonstrated biomedical applications, are highly optimized structures for use as filtering systems, templates for biomineralization as well as metallization in order to produce catalysts.
    International journal of biological macromolecules 08/2010; 47(2):141-5. · 2.37 Impact Factor
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    ABSTRACT: The aim of this study was to determine the compound strength of the fixation between 2 blocks of synthetic bone using ultrasound activated resorbable pins (regarding drill hole diameter) and compare them to fixation with titanium miniscrews. Resorbable pins were up to 17 mm long. Two synthetic bone blocks (Sawbone) were fixed by either a resorbable pin or miniscrew osteosynthesis. Maximum tensile forces were determined mechanically. Pin lengths of 7 mm, 11 mm, and 17 mm were analyzed in relation to different drill hole diameters. The ideal drill hole configuration was a combination of diameters of 2.1/1.6 mm (in a lag screw configuration). Mean maximum tensile force was 80 N for 7 mm pins (105 N/11 mm, 69 N/17 mm). In comparison, tensile forces of titanium screws were 20 N (7 mm), 97 N (11 mm), and 135 N (17 mm). Osteosynthesis by resorbable pins reached equal compound strength levels compared with titanium miniscrews. This in vitro study was the basis for a clinical trial of ultrasound-guided resorbable pin osteosynthesis.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 10/2009; 109(1):79-85. · 1.50 Impact Factor
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    ABSTRACT: The purpose of this study was to determine whether fixation of cranial bone segments using ultrasonically welded pin osteosynthesis showed differences in mechanical stability as compared to fixation of cranial bone segments using screw osteosynthesis. Right and left cranial bone segments from each of 16 young sheep were obtained by craniotomy and re-fixed: on the right with a mesh plate and pins, and on the left with a mesh plate and screws. All osteosynthesis materials consisted of PDLLA, fully amorphous polyactid. A total of 167 cranial bone / mesh plate segments from 16 animals were investigated; 84 segments were pin-fixed and 83 segments were screw-fixed. The implantation time of the re-fixed segments ranged from 1 day to 196 days. The mechanical methods chosen for simulation of stress on the bone segment bonds were two bending tests (horizontal and vertical directions) and a tensile test. The values obtained in the mechanical tests indicate differences in the bond strength between the pin- and screw- fixation methods over the length of in vivo implantation time. The mechanical stability of the ultrasonically welded pin osteosynthesis bonds over the screw osteosynthesis bonds proved to be statistically significant. The implication of these findings should also be relevant in the field of medicine.
    Journal of Materials Science Materials in Medicine 07/2008; 19(6):2255-9. · 2.14 Impact Factor
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    ABSTRACT: We compared a conventional resorbable screw osteosynthesis with a resorbable, ultrasound-activated pin osteosynthesis, and studied mechanical load capacity and operative handling. This new form of osteosynthesis aims to reduce operation times, and to avoid torque loads and screw fractures to achieve stability. A sheep craniotomy model simulated an operation for dysmorphia on an infant skull. Two rectangular craniotomies of equal size were created in 13 lamb skulls, and each refixed by different means: the first by mesh and 20 screws, and the second by mesh with 20 pins inserted with ultrasound activation. All osteosynthesis material consisted of resorbable amorphous poly-(d,l)-lactide (PDLLA) (Resorb-X, KLS Martin, Tuttlingen, Germany). The insertion time was recorded. The animals were killed at different times, and areas of the healing skull including the plates and pins or screws were removed and divided into sections, which were then tested. In total 74 pin-fixed and 77 screw-fixed samples were obtained. Bending and tensile tests were used to simulate different forms of loading. The time required for the insertion of pins was significantly shorter than for screws. The mechanical tests showed differences in the stability of the bond between the osteosynthesis plate and bone that depended on the osteosynthesis system and the length of time it was in the animal. The pin osteosynthesis gave a stable mechanical load capacity, which was significantly different from that of screw osteosynthesis. Advantages of ultrasound-assisted, resorbable, pin osteosynthesis, include optimum operative handling, reduced insertion time, avoidance of fractures of the fixation elements and higher three-dimensional load capacity.
    British Journal of Oral and Maxillofacial Surgery 10/2007; 45(6):451-6. · 2.72 Impact Factor
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    ABSTRACT: Natural structural biomaterials of marine origin including mollusc shells, sponges and corals not only provide an abundant source of novel bone and cartilage replacements but also inspire investigations to develop nano-sized biomimetic composites. This study presents a characterisation of the ultrastructure of the deep-sea Bamboo coral (Anthozoa: Gorgonacea: Isididae) and the nanostructure of some interstitial surfaces with respect to biomineralization phenomena. The skeletons of the corals examined exhibit jointed axes of large bony calcareous structures alternated with smaller proteinaceous nodes of gorgonin, giving the skeletal remains of the organism a digitated appearance, like terrestrial bamboo. To test the hypothesis that bamboo coral internodes exhibit bone-like mechanical and biochemical properties, structural and biochemical analyses of these natural biomineral composites and separation of proteinaceous components was performed. Due to its high potential for colonization with both human osteoblasts and osteoclasts, the organic matrix, composed of an acidic fibrillar protein framework, proved to be a very successful model for possible applications in tissue engineering. The material properties of the calcareous internodes correlate well with the material property charts for materials used in orthopedic surgery, though denser and stronger than bone. Results of the present study also clearly indicate the quinonproteinaceous nature of the gorgonin. On the basis of the high biomimetic potential of the results obtained, the use of Isididae corals as “living bone implants” as well as their biotechnological aquacultural cultivation seems to be promising for the near future.Biomaterialstrukturen in der Tiefsee-Bambuskoralle (Anthozoa: Gorgonacea: Isididae): Perspektiven für die Entwicklung von Knochenimplantaten und Templaten für das Tissue-EngineeringNatürlich strukturierte Biomaterialien marinen Ursprungs, z. B. Schalen von Weichtieren, Schwämme und Korallen, stellen nicht nur eine üppige Quelle von Knochen- und Knorpelersatzmaterial dar, sondern auch eine Inspiration für die Entwicklung biomimetischer Komposite im Nanobereich. Die vorliegende Publikation stellt die Charakterisierung der Ultrastruktur der Tiefsee-Bambuskoralle (Anthozoa: Gorgonacea: Isididae) sowie der Nanostruktur innerer Oberflächen im Zusammenhang mit Biomineralisationsphänomenen vor. Die untersuchten Korallenskelette haben lange, verbundene knochenartige Kalkstrukturen, die sich mit kleineren, aus dem Protein Gorgonin bestehenden, Nodi abwechseln, was dem Ganzen ein segmentiertes Aussehen gibt, wie beim Bambus. Um die Annahme zu prüfen, dass die Internodien der Bambuskoralle knochenähnliche mechanische und biochemische Eigenschaften aufweisen, wurden Struktur- und biochemische Untersuchungen an den natürlichen Biomineralkompositen vorgenommen sowie der Proteinanteil separiert und gesondert untersucht. Aufgrund der gezeigten guten Eignung als Substrat für die Besiedlung mit humanen Osteoblasten und Osteoklasten ist diese organische Matrix, bestehend aus einem sauren fibrillären Proteinnetzwerk, ein aussichtsreiches Modell für Anwendungen im Tissue Engineering. Die Materialeigenschaften der kalkartigen Internodien korrelieren gut mit denen von Materialien wie sie in der orthopädischen Chirurgie Verwendung finden, sie sind sogar dichter und fester als Knochen. Die Resultate der vorliegenden Untersuchungen zeigen weiterhin klar die Natur des Grogonin als ein Chinoprotein. Angesichts des großen biomimetischen Potentials, das sich aus den erhaltenen Ergebnissen ergibt, erscheint eine Verwendung der Isididae-Korallen als „lebende Knochenimplantate” und deren Zucht in biotechnologischer Aquakultur für die nahe Zukunft aussichtsreich.
    Materialwissenschaft und Werkstofftechnik 06/2006; 37(6):552 - 557. · 0.51 Impact Factor
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    ABSTRACT: 186 Glass sponges (class Hexactinellidae, Porifera) inhabit mostly deep-sea areas of all oceans [14, 21] anchoring themselves in bottom sediments using sili-con-bearing spicules (Fig. 1a). The interest to studies of these marine organisms is due to the following reasons. Hexactinellidae are among the most ancient multicellu-lar organisms, whose fossil remnants could be retraced to the early Proterozoic [3, 19]. Therefore, studies of these "living fossils" are important in terms of evolu-tion and phylogeny [15]. The peculiarities of the struc-tural organization of spicules in glass sponges, by their mechanical, physico-chemical, and optical properties, allow the latter to be referred to as unique biological materials of natural origin. The spicules are 0.5 (Hya-lonema sp.) to 100 mm (Monorhaphis sp.) in diameter and from several centimeters (Euplectella sp.) to 1 m (Hyalonema sp.) and even more than 2 m (Monorha-phis sp.) long [23]. It is generally accepted that the min-eral component of the spicules represents silicon diox-ide in the form of amorphous opal A [7]. However, in our opinion, the presence of only the silicate compo-nent cannot explain the great flexibility of the spicules that allow us to tie a spicule into a bundle (Fig. 1b). According to our ideas, such a peculiarity of spicules in the sponges must be due to the presence of a struc-tural carcass of organic nature, like, for example, the spongin skeleton of horny sponges of the genus Veron-gula (see [8]). The isolation of an organic component from any natural material belonging to the category of biomin-eral structural compounds is indispensable to choose the most efficient technique of demineralization of the latter. According to our concept, the effectiveness of this technique should be based not on the fast dissolu-tion of the inorganic component, but, in contrast, on a slow process of demineralization that would spare the organic components of biominerals and would not result in artifacts. Traditional methods of demineralization of silicon spicules in sponges, both Demospongiae and Hexacti-nellida, have been known from the middle of the nine-teenth century [16]. They were based on the usage of hydrofluoric acid solutions in different concentrations and are still implemented at present [23]. The crucial remark of Bütschli [4], that the usage of hydrofluoric acid for desicification of spicules could result in arti-facts, was actually confirmed only in 2004 [6]. Taking into account that the spicules of glass sponges are comprised of amorphous silicon dioxide,
    Russian Journal of Marine Biology 03/2006; 32:1063-740. · 0.29 Impact Factor
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    ABSTRACT: Glass sponges of the class Hexactinellida are a group of the most ancient multicellular animals, whose fossil remnants from the early Proterozoic have been registered. In order to demineralize the skeletal structures of the glass sponge Hyalonema sieboldi, we have used for the first time a strategy of slow leaching of the silicon-bearing component, based on the usage of alkaline solutions of sodium hydroxide, sodium dodecyl sulfate, and an anionic biosurfactant of a rhamnolipid nature. The obtained data unequivocally corroborate the presence of a fibrillar protein matrix functioning as a basis for silicon biomineralization in the basal spicules of H. sieboldi. Also, it has been found for the first time that the protein matrix is constructed of a collagenous protein. The technical approach proposed here might appear important for the study of the structural organization of skeletons in other silicon-bearing animals and, in an applied aspect, to work out new biomaterials for implantology and biocomposites, in order to use the latter as bioactive additives.
    Russian Journal of Marine Biology 01/2006; 32(3):186-193. · 0.39 Impact Factor
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    ABSTRACT: This study involves a characterization of the ultrastructure of deep-sea Bamboo (Isididae) corals and the nanostructure of some interstitial surfaces with respect to biomineralization phenomena. These jointed corals consist of bony calcareous structures alternated by proteinaceous nodes of gorgonin, giving the skeletal remains of the organism a unique fingerlike appearance. The role of gorgonin in biomineralization in octocorallia is poorly understood. The purpose of the present study was to obtain some understanding of the role of gorgonin-associated mineralization. Isidid samples were collected from Heceta Bank off the coast of Oregon, USA, at a water depth of 1148 meters. Decalcification of samples was carried out using 7.4 pH EDTA solution. Quino-proteins from gorgonin-containing nodes were isolated according to a 2.5 M NaOH extraction procedure. The ultrastructural morphology of the coral surface and of axial internodes and node channels was characterized by means of ESEM and SEM. Physico-chemical analysis was performed using FTIR, EDX and XRD techniques. The following results were obtained: The calicoblastic epithelium covering of the middle channel of the gorgonin distal node observed by means of SEM appears brownish in light microscopy and differs drastically from the transparent calicoblastic surface of the axial channel, also from a nanostructural point of view. Mineralized fibrous structures can be observed on the both interfaces of bilayered (layer thickness about 150 nm) epithelium from the middle channel of the gorgonin-containing node. The ca. 70 nm large spherical Ca-carbonate formations are tightly distributed on microfibrils, which are placed or formed on the gorgonin intersurface. No mineral phase formations were observed on the surface of the gorgonin layer which was free of microfibrils. The result obtained could be explained well by the impossibility of an interaction between non-reactive oxygen residues of gorgonins’ quino-proteins and Ca-ions. However, gorgonin layers themselves could be templates for the formation of protein microfibrils, on which the biomineralization processes could correspondingly start. A comprehensive understanding of gorgonin-containing nodes with respect to chemical composition, structure, and mineralization behaviour may prove to be a novel model for biomimetic synthesis of biomaterials resistant to calcification.
    9th International Symposium on Biomineralization, Pucón, Chile; 12/2005
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    ABSTRACT: Deep-sea bamboo corals [Calcaxonia: Isididae] show promise in biomaterial applications. These jointed corals consist of bony calcareous structures alternated by proteinaceous nodes of gorgonin, giving the skeletal remains of the organism a unique fingerlike appearance. A comprehensive understanding of the bamboo coral internodes with respect to chemical composition, structure, and mineralization behaviour may prove to be a novel model for biomimetic synthesis of biomaterials. To test our hypothesis that bamboo coral internodes exhibit bone-like mechanical and biochemical properties, structural (SEM, TEM, AFM, LSM, XRD, FTIR, Raman) and biochemical (HPLC, PAAG-Electrophoresis) analyses of these natural biomineral composites and extracted proteinaceous components were performed. The following results were obtained: Due to its high potential for colonisation with both human osteoblasts and osteoclasts, the organic matrix, composed of an acidic fibrillar protein framework, showed itself to be a very successful model for possible applications in tissue engineering. The resorption of the calcite-containing fragment of the coral implant was faster than that of bioceramics. The material properties of the coral axial internode measured, namely Young’s modulus (160 ± 35 GPa, n=20), density (2.7 ± 0.02 g/cm3) and flexural strength (107 N/mm2) correlate well with the material property charts for materials used in orthopaedic surgery. On the basis of the high biomimetic potential of the results obtained, we propose that biotechnological processes for the aquacultural cultivation of Isididae corals as “living bone implants” should be developed in the near future.
    Third International Symposium on Deep-Sea Corals Science and Management (ISDSC), Miami, Florida, USA; 11/2005
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    ABSTRACT: Natural structural biomaterials of marine origin including mollusc shells, sponges and corals not only provide an abundant source of novel bone and cartilage replacements but also inspire investigations to develop nano-sized biomimetic composites. Natural coral has been used as a bone substitute for more than 10 years in orthopaedic, trauma, craniofacial, dental, and neurosurgery. At present, the tropical coral genera Porites, Alveopora, Acropora, and Goniopora are being used as bone substitutes; these are the only families known to have the correct pore diameter and the ability to connect property with bone. The deep-sea corals of Isididae family, also known as bamboo corals, are presently attracting increased scientific attention. These deep-sea jointed corals consist of bony calcareous structures alternated by proteinaceous nodes of gorgonin, giving the skeletal remains of the organism a unique fingerlike appearance. Gorgonin is known as a keratin-like biomaterial with elastic properties containing polyphenolic compounds. The mineral phase of these octocorals consists of calcite. The aim of the present study was to investigate for the first time the in situ behaviour of bamboo coral axial internodes as bone implants in an animal model (dog) and of the organic matrix of demineralised coral internodes as a template for tissue engineering. The demineralization procedure was carried out using OsteosoftTM solution at 37°C for 7 days. The nanostructure of the organic matrix obtained was analysed using SEM, TEM and LSM techniques. In addition, its nature was characterised by performing SDS-PAAG electrophoresis and amino acid analysis. The presence of calcite was determined using XRD, FTIR and Raman analysis. The implanted coral fragments were sterilized with formaldehyde vapour and subsequently gamma radiation (25 kGr). The bamboo coral implant was implanted in a trepanation hole in a dog’s tibia. The implantation zone was monitored using X-ray techniques. The duration of the experiment was 10 months. Afterwards a biopsy was performed under calypsol anaesthetic, the animal was not killed and continued to live without any handicap. The following results were obtained: Due to its high potential for colonisation with both human osteoblasts and osteoclasts, the organic matrix, composed of an acidic fibrillar protein framework, showed itself to be a very successful model for possible applications in tissue engineering. The resorption of the calcite-containing fragment of the coral implant was faster in relation to that of bioceramics. No infection or rejection of coral implant was observed. The material properties of the coral axial internode measured, namely Young’s modulus (160 ± 35 GPa, n=20), density (2.7 ± 0.02 g/cm3) and flexural strength (107 N/mm2) correlate well with the material property charts for materials used in orthopaedic surgery. On the basis of the high biomimetic potential of the results obtained, we propose that biotechnological processes for the aquacultural cultivation of Isididae corals as “living bone implants” should be developed in the near future.
    8th Essen Symposium on Biomaterials and Biomechanics: Fundamental and Clinical Applications, Essen, Germany; 09/2005
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    ABSTRACT: Deep-sea invertebrates, including glass sponges, provide an abundant source of very unusual skeleton structures and inspire investigations aiming to gain a better understanding of biomineralization mechanisms, which can be used to develop new biomimetic based biomaterials. The study focused on the spicules of Hyalonema sieboldi Gray 1835, which are glassy fibres several millimetres in diameter and up to one metre in length – a size which is exceptional for a siliceous biological structure. They exhibit remarkable flexibility, thus giving the impression of being an almost unbreakable glass, which can be easily bent into a full circle. The origin and the possible role of the organic matrix within these silica-containing skeletal formations are still unknown. Here, a new approach is described for the desilification of glass sponge spicules based on a slow etching procedure. To test our hypothesis that an organic matrix within the H. sieboldi spicules is responsible for the extraordinary mechanical properties, structural (SEM, TEM, AFM) and biochemical (HPLC, PAAG-Electrophoresis, MALDI) analyses of these glassy composites and extracted proteinaceous components were performed.
    VDI-Berichte 01/2005; 1920:163-166.