Distribution by Scientific Domains

Kinds of Biomaterial

  • novel biomaterial

  • Selected Abstracts

    Synthesis of Nonwoven Nanofibers by Electrospinning , A Promising Biomaterial for Tissue Engineering and Drug Delivery,

    N. Naveen
    PHB nanofibers are synthesized by electrospinning of a PHB solution prepared using HFIP as the solvent. The nanofibrous scaffold supports rapid cell growth with normal morphology and attains a viability of 87% after 48,h. Kanamycin sulphate-loaded PHB nanofiber mats are synthesized, with the antibiotic on the surface and sandwiched within the nanofiber mats: their antimicrobial property is proved by the good zone of inhibition tested against Staphylococcus aureus. The drug shows more than 95% release within 8,h. These results indicate that nanofibers loaded with the antibiotic have potential applications as a template for tissue engineering and as a drug carrier. [source]

    Porous TiNi Biomaterial by Self-Propagating High-Temperature Synthesis,

    J.S. Kim
    Abstract Porous TiNi shape-memory alloy (TiNi SMA) bodies with controlled pore structure were produced from the (Ti+Ni) powder mixture by self-propagating high-temperature synthesis (SHS) method. The effect of processing variables such as the kind of starting powders, ignition temperature and preheating schedule on the behavior of combustion wave propagation, the formation of phases and pore structure was investigated. The relationship between pore structure and mechanical properties was also investigated. An in vivo test was performed to evaluate bone tissue response and histocompatibility of porous TiNi SMA using 15 New Zealand white rabbits. No apparent adverse reactions such as inflammation and foreign body reaction were noted on or around all implanted porous TiNi SMA blocks. Bone ingrowth was found in the pore space of all implanted blocks. [source]

    A Gene Therapy Technology-Based Biomaterial for the Trigger-Inducible Release of Biopharmaceuticals in Mice

    Michael M. Kämpf
    Abstract Gene therapy scientists have developed expression systems for therapeutic transgenes within patients, which must be seamlessly integrated into the patient's physiology by developing sophisticated control mechanisms to titrate expression levels of the transgenes into the therapeutic window. However, despite these efforts, gene-based medicine still faces security concerns related to the administration of the therapeutic transgene vector. Here, molecular tools developed for therapeutic transgene expression can readily be transferred to materials science to design a humanized drug depot that can be implanted into mice and enables the trigger-inducible release of a therapeutic protein in response to a small-molecule inducer. The drug depot is constructed by embedding the vascular endothelial growth factor (VEGF121) as model therapeutic protein into a hydrogel consisting of linear polyacrylamide crosslinked with a homodimeric variant of the human FK-binding protein 12 (FM), originally developed for gene therapeutic applications, as well as with dimethylsuberimidate. Administrating increasing concentrations of the inducer molecule FK506 triggers the dissociation of FM thereby loosening the hydrogel structure and releasing the VEGF121 payload in a dose-adjustable manner. Subcutaneous implantation of the drug depot into mice and subsequent administration of the inducer by injection or by oral intake triggers the release of VEGF121 as monitored in the mouse serum. This study is the first demonstration of a stimuli-responsive hydrogel that can be used in mammals to release a therapeutic protein on demand by the application of a small-molecule stimulus. This trigger-inducible release is a starting point for the further development of externally controlled drug depots for patient-compliant administration of biopharmaceuticals. [source]

    Periodontal repair in dogs: space-providing ePTFE devices increase rhBMP-2/ACS-induced bone formation

    Ulf M.E. Wikesjö
    Abstract Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) technologies have been shown to enhance alveolar bone formation significantly. Biomaterial (carrier) limitations, however, have restricted their biologic potential for indications where compressive forces may limit the volume of bone formed. The objective of this proof-of-principle study was to evaluate the potential of a space-providing, macroporous ePTFE device to define rhBMP-2-induced alveolar bone formation using a discriminating onlay defect model. Methods: Routine, critical size, 5,6 mm, supra-alveolar, periodontal defects were created around the third and fourth mandibular premolar teeth in four young adult Hound Labrador mongrel dogs. All jaw quadrants received rhBMP-2 (0.4 mg) in an absorbable collagen sponge (ACS) carrier. Contralateral jaw quadrants in subsequent animals were randomly assigned to receive additionally the dome-shaped, macroporous ePTFE device over the rhBMP-2/ACS implant or no additional treatment. The gingival flaps were advanced to cover the ePTFE device and teeth, and sutured. Animals were scheduled for euthanasia to provide for histologic observations of healing at 8 weeks postsurgery. Results: Healing was uneventful without device exposures. New bone formation averaged (±SD) 4.7±0.2 mm (98%) and 4.5±0.4 mm (94%) of the defect height, respectively, for jaw quadrants receiving rhBMP-2/ACS with the ePTFE device or rhBMP-2/ACS alone (p>0.05). In contrast, the regenerated bone area was significantly enhanced in jaw quadrants receiving rhBMP-2/ACS with the ePTFE device compared to rhBMP-2/ACS alone (9.3±2.7 versus 5.1±1.1 mm2; p<0.05). Cementum formation was similar for both treatment groups. Ankylosis compromised periodontal regeneration in all sites. Conclusions: The results suggest that the novel space-providing, macroporous ePTFE device appears suitable as a template to define rhBMP-2/ACS-induced alveolar bone formation. Zusammenfassung Hintergrund: Es wurde gezeigt, dass das rekombinante menschliche knochenmorphogenetische Protein 2 (rhBMP-2) die alveoläre Knochenbildung signifikant erhöht. Limitationen des Biomaterials (Träger) haben jedoch die biologischen Potenzen des Materials für die Indikationen, wo komprimierende Kräfte das Volumen des zu bildenden Knochen limitierten, eingeengt. Das Ziel dieser prinzipiellen geprüften Studie war die Evaluation der Platzhalterfunktion einer makroporösen e-PTFE Membran, um die von rhBMP-2 induzierten Knochenbildung unter Nutzung eines differenzierenden Onlaydefektmodells zu definieren. Methoden: Routinemäßig wurden supraalveoläre parodontale Defekte mit der kritischen Größe von 5,6 mm um die dritten und vierten Prämolaren bei 4 jungen adulten Labrodormischhunden geschaffen. Alle Quadranten erhielten rhBMP-2 (0.4 mg) in einem resorbierbaren Kollagenschwamm (ACS). Kontralaterale Quadranten bei den aufeinander folgenden Tieren wurden zufällig ausgewählt, um zusätzlich eine domförmige makroporöse e-PTFE Membran über das rhBMP-2/ACS Implantat oder keine zusätzliche Therapie zu erhalten. Die gingivalen Lappen wurden so präpariert, dass sie die e-PTFE Membran und Zähne bedeckten und vernäht. Die Tiere wurden 8 Wochen nach der Operation getötet und für histologische Untersuchungen vorbereitet. Ergebnisse: Die Heilung war komplikationslos ohne Exposition der Membran. Die neue Knochenbildung betrug durchschnittlich (±SD) 4.7±0.2 mm (98%) und 4.5±0.4 mm (94%) der Defekthöhe für die Quadranten, die rhBMP-2/ACS mit der e-PTFE Membran erhielten oder rhBMP-2/ACS allein (p>0,05). Im Kontrast dazu war das regenerierte Knochenfeld signifikant erweitert bei den Kieferquadranten, die rhBMP-2/ACS mit e-PTFE Membran erhielten im Vergleich zu denjenigen mit rhBMP-2/ACS allein (9.3±2.7 vs. 5.1±1.1 mm2; p<0.05). Die Zementbildung war in beiden Behandlungsgruppen ähnlich. Ankylosen gefährdeten die parodontalen Regeneration in allen Flächen. Schlussfolgerungen: Die Ergebnisse zeigen, dass die neue makroporöse Platzhalter e-PTFE Membran als Schablone nützlich ist, um die rhBMP-2/ACS induzierte alveoläre Knochenbildung zu betonen. Résumé Contexte: Des technologies utilisant la protéine-2 osseuse morphogénétique humaine recombinée (rhBMP-2) ont montré qu'elle permettait d'augmenter significativement la formation d'os alvéolaire. Les limites du biomatériel (vecteur), cependant, ont restreint leur potentiel biologique aux indications pour lesquels des forces compressives pourraient limiter le volume d'os en formation. L'objectif de cette étude fut d'évaluer le potentiel d'un dispositif en ePTFE macro-poreux permettant de créer un espace pour définir la formation d'os alvéolaire induit par la rhBMP-2 en utilisant un modèle discriminatoire de lésion. Méthodes: Des lésions parodontales supra-alvéolaires de taille critique, 5,6 mm, furent créées autour des troisièmes et quatrièmes prémolaires chez 4 Labrador adultes. Chaque quadrant a été traité par des éponges de collagène résorbables utilisé comme vecteur (ASC) contenant rhBMP-2 (0.4 mg). Les quadrants contralatéraux des animaux furent aléatoirement distribués pour recevoir (ou pas) en plus un dispositif macro-poreux en ePTFE, en forme de dôme sur les implants de rhBMP-2/ACS. Les lambeaux furent déplacés pour recouvrir le dispositif en ePTFE et les dents et suturés. Les animaux furent sacrifiés après 8 semaines pour fournir des observations histologiques de la cicatrisation. Résultats: La cicatrisation ne posait pas de problèmes et on ne nota pas d'exposition des dispositifs. La moyenne de la formation osseuse était de (±SD) 4.7±0.2 mm (98%) et 4.5±0.4 mm (94%) de la hauteur de la lésion, respectivement, pour les quadrants ayant été traités par la rhBMP-2/ACS avec le dispositif en ePTFE ou la rhBMP-2/ACS seule (p>0.05). A l'inverse, la surface osseuse régénérée était significativement plus importante dans les quadrants traités par la rhBMP-2/ACS et les dispositifs en ePTFE par rapport au site traités seulement par la rhBMP-2/ACS (9.3±2.7 vs. 5.1±1.1 mm2; p<0.05). La formation cémentaire était similaire pour les deux groupes de traitement. L'ankylose compromettait la régénération parodontale dans tous les sites. Conclusions: Ces résultats suggèrent que le dispositif en ePTFE macro-poreux, qui assure un espace, semble convenir comme standard pour définir la formation osseuse induite par la rhBMP-2/ACS. [source]

    The effect of a fibrin glue on the integration of Bio-Oss® with bone tissue

    An experimental study in labrador dogs
    Abstract Background: Bio-Oss® is a deproteinized bovine mineral used in bone augmentation procedures. The particles are often mixed with a protein product (Tisseel®) to form a mouldable graft material. Aim: The aim of the present experiment was to study the healing of self-contained bone defects after the placement of Bio-Oss® particles alone or mixed with Tisseel® in cylindrical defects in the edentulous mandibular ridge of dogs. Material and methods: In 4 labrador dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. 3 months later, 3 cylindrical bone defects, 4 mm in diameter and 8 mm in depth, were produced in the right side of the mandible. Following a crestal incision, full thickness flaps were raised and the bone defects were prepared with a trephine drill. The defects were filled with Bio-Oss® (Geistlich Biomaterials, Wolhuser, Switzerland) particles alone or mixed with Tisseel® (Immuno AG, Vienna, Austria), or left "untreated". A collagen membrane (Bio-Gide®, Geistlich Biomaterials, Wolhuser, Switzerland) was placed to cover all defects and the flaps were sutured. 2 months later, the defect preparation and grafting procedures were repeated in the left side of the mandible. After another month, the animals were sacrificed and biopsies obtained from the defect sites. Results: Bio-Oss® -treated defects revealed a higher percentage of contact between graft particles and bone tissue than defects treated with Bio-Oss®+ Tisseel® (15% and 30% at 1 and 3 months versus 0.4% and 8%, respectively). Further, the volume of connective tissue in the Bio-Oss® treated defects decreased from the 1 to the 3 month interval (from 44% to 30%). This soft tissue was replaced with newly formed bone. In the Bio-Oss®+ Tisseel® treated defects, however, the proportion of connective tissue remained unchanged between 1 and 3 months. Conclusion: The adjunct of Tisseel® may jeopardize the integration of Bio-Oss® particles with bone tissue. Zusammenfassung Hintergrund: Bio-Oss® ist ein entproteiniertes Mineral vom Schwein, was bei knöchernen Augmentationen verwendet wird. Die Partikel werden oft mit einem Proteinprodukt gemischt, um ein formbares Implantationsmaterial zu erhalten. Ziel: Das Ziel des vorliegenden Experimentes war das Studium der Heilung von selbst-erhaltenden Knochendefekten nach der Anwendung von Bio-Oss® Partikeln allein oder vermischt mit Tisseel® in zylindrischen Defekten im zahnlosen unteren Kieferkamm von Hunden. Materal und Methoden: Bei 4 Labradorhunden wurden die 2., 3. und 4. unteren Prämolaren beidseitig extrahiert. 3 Monate später wurden 3 zylindrische Knochendefekte, 4 mm im Durchmesser und 8 mm tief, auf der rechten Seite des Unterkiefers hergestellt. Nach einer krestalen Incision wurde ein voller Mukoperiostlappen mobilisiert und die knöchernen Defekte mit einem Trepanfräser präpariert. Die Defekte wurden mit Bio-Oss® Partikeln (Geistlich Biomaterial, Wolhuser, Schweiz) allen oder gemischt mit Tisseel® (Immuno AG, Wien, Österreich) gefüllt oder blieben "unbehandelt". Eine Kollagenmembran (Bio-Gide®, Geistlich Biomaterial, Wolhuser, Schweiz) wurde zur Abdeckung über alle Defekte gelegt und die Lappen reponiert und vernäht. 2 Monate später wurden die Defektpräparationen und die Implantationsmaßnahmen auf der linken Seite des Unterkiefers widerholt. Nach einem weiteren Monat wurden die Tiere getötet und Biopsien von den Defektseiten gewonnen. Ergebnisse: Mit Bio-Oss® behandelte Defekte zeigten einen höheren Prozentsatz von Kontakt zwischen Implantationsmaterial und Knochengewebe als die Defekte, die mit Bio-Oss® und Tisseel® behandelt worden waren (15% und 30% zum 1. Monat und 3. Monat versus 0.4% und 8%). Weiterhin verringerte sich das Volumen des Bindegewebes in den mit Bio-Oss® behandelten Defekten vom 1. zum 3. Monat (von 44% zu 30%). Dieses Weichgewebe wurde mit neu gebildetem Knochen ersetzt. In dem mit Bio-Oss® und Tisseel® behandelten Defekten blieb die Verteilung des Bindegewebes zwischen dem 1. und 3. Monat unverändert. Zusammenfassung: Die Zugabe von Tisseel® kann die Integration von Bio-Oss® Partikeln mit Knochengewebe behindern. Résumé Origine: Le Bio-Oss® est un minéral bovin déprotéine utilisé pour les épaississements osseux. Les particules sont souvent mélangées avec un produit protéiné (Tisseel®) pour former un matérial de greffe malléable. But. Le but de l'étude présente a été d'étudier la guérison des lésions osseuses après le placement de particules de Bio-Oss® seules ou mélangées au Tisseel® dans des lésions cylindriques au niveau de la mandibule édentée de labradors. Matériaux et méthodes: Chez 4 labradors les 2ièmes, 3ièmes et 4ièmes prémolaires inférieures ont été avulsées bilatéralement. 3 mois après, 3 lésions osseuses et cylindriques de 4 mm de diamètre et de 8 mm de profondeur ont été produites du côté droit de la mandibule. A la suite d'une incision crestale, des lambeaux d'épaisseur complète ont été relevés et les lésions osseuses préparées avec un trépan. Les lésions ont été comblées par des particules de Bio-Oss® seul (Geistlich Biomaterials, Wolhuser, Suisse) ou mélangées au Tisseel® (Immuno AG, Vienne) ou laissées non-traitées. Une membrane collagène (Bio-Gide®, Geistlich Biomaterials, Wolhuser, Suisse) a été placée pour recouvrir toutes les lésions et les lambeaux ont ensuite été suturés. 2 mois après, les processus précités ont été répétés au niveau gauche de la mandibule. 1 mois plus tard, les animaux ont été tués et les biopsies prélevées. Résultats: Les lésions traitées par le Bio-Oss® ont révélé un % plus important de contact entre les particules du greffon et le tissu osseux que les lésions traitées avec le Bio-Oss®+Tisseel® (respectivement 15% à 30% à 1 et 3 mois versus 0.4% et 8%). De plus le volume de tissu conjonctif dans les lésions traitées par Bio-Oss® diminuait du mois 1 au mois 3, de 44 à 30%. Ce tissu mou a été remplacé par un os néoformé. Dans les lésions traitées par Bio-Oss®+Tisseel®, la proportion de tissu conjonctif demeurait inchangée entre les mois 1 et 3. Conclusions: L'addition de Tisseel® peut mettre en péril l'intégration des particules de Bio-Oss® au tissu osseux. [source]

    in vitro Evaluation of Biodegradable Poly(butylene succinate) as a Novel Biomaterial

    Haiyan Li
    Abstract Summary: Poly(butylene succinate) (PBSU) can be easily synthesized by condensation polymerization of the starting materials of succinic acid and butan-1,4-diol. It has good degradability and possesses excellent processability. Due to these advantages, PBSU was first evaluated in the present study for its potential application as a novel biomaterial. The in vitro biocompatibility of the PBSU was evaluated by monitoring proliferation and differentiation of osteoblasts cultured on the PBSU film substrates for different periods. The results showed that the PBSU was biocompatible as the osteoblasts could proliferate and differentiate on the PBSU plates. In addition, the hydrolytic degradation behavior of the PBSU films in the phosphate-buffered saline (PBS) was also investigated and the results suggested that the PBSU degraded in the PBS solution with the same behavior as that of the degradable poly(, -hydroxyesters). In addition to the biocompatibility and hydrolytic degradation, some physical properties, including hydrophilicity, and mechanical and thermal properties of the PBSU substrates, were also determined and the results revealed that the PBSU was hydrophilic and ductile with excellent processability. The biocompatibility of the PBSU, together with the advantages of hydrolytic degradability, hydrophilicity, and excellent processability, indicated that PBSU has the potential to be used as a biomaterial for tissue repair. Alkaline phosphate activity of osteoblasts cultured on PBSU and TCPS substrates for different time periods. [source]

    Mucin Coatings Suppress Neutrophil Adhesion to a Polymeric Model Biomaterial

    Tomas Sandberg
    Abstract Following our recent study on the fractionation, characterization, and model adsorption of mucins derived from bovine salivary glands (BSM), porcine stomach scrapings (PGM), and human whole saliva (MG1), we here present a microscopic evaluation of the interactions between mucin-coated substrates and human neutrophils. Our results show that surface-coating with BSM, PGM, and MG1 can be effectively used to suppress the adhesion of neutrophils to a polymeric model biomaterial (Thermanox). Neutrophil morphologies found on Thermanox substrates coated with mucins resemble those observed for nonactivated neutrophils found in circulation. Notably, low neutrophil adhesion can be obtained at a significantly lower coating concentration (0.125 mg/mL) for the compositionally complex MG1 mucin than for the relatively pure BSM and PGM mucins (1 mg/mL). Furthermore, since coating at a low BSM and PGM concentration (0.25 mg/mL) results in higher cell counts and more spread cells than in the high-concentration case, we suggest that dense mucin surface packing is critical for good coating performance. In conclusion, the present study demonstrates how mucins from three different sources, of different compositional and structural status, efficiently can be used to suppress neutrophil adhesion and activation. This finding makes them potent candidates for use as biomaterial coatings. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source]

    Electron Backscatter Diffraction Study of Brachiopod Shell Calcite , Microscale Phase and Texture Analysis of a Polycrystalline Biomaterial

    Wolfgang W. Schmahl
    Abstract Electron backscatter diffraction (EBSD) is an easy to use and highly automated microdiffraction method suitable for the determination of crystallographic phase and crystallite orientation. The high level of hierarchical structural organization in the shells of marine organisms was studied. Calcite brachiopod shell materials were found to belong to three types of microstructure: nano- to microcrystalline layers of acicular crystals, fiber composites with calcite single crystal fibers with [uv0] morphological axes, and material formed by columnar crystals with [001] morphological axes selected by competitive growth. [source]

    Biomorphic Silicon Carbide Coated with an Electrodeposition of Nanostructured Hydroxyapatite/Collagen as Biomimetic Bone Filler and Scaffold,

    M. Lelli
    Abstract The paper describes the method of preparation and chemical/physical characterization of a new biomaterial to be used as a bone substitute and bone-tissue engineering scaffold, which synergistically joins a porous bio-inspired morphology and the mechanical properties of biomorphic silicon carbide (BioSiC) with the surface bioactivity of a nanostructured hydroxyapatite/collagen biomimetic coating. FT-IR spectroscopy and XRD techniques are utilized to determine the chemical coating's composition. The morphology and size of the inorganic and protein components are investigated by TEM. The characteristic morphology of BioSiC channels and pores, which differ as a function of the transversal or longitudinal cross-section and with etching time, are investigated by SEM. Natural wood transformed into BioSiC acts as a cathode in an electrochemically assisted process that produces on its surface a biomimetic coating of hydroxyapatite nanocrystals and reconstituted type I collagen fibrils, producing an innovative apatite/collagen biomimetic porous bone filler and scaffold for tissue engineering. [source]

    Quantitative Chemical Mapping of Relevant Trace Elements at Biomaterials/Biological Media Interfaces by Ion Beam Methods

    Edouard Jallot
    The definition of biomaterial as proposed by the European Society for Biomaterials in 1986 puts forward the overall importance of the notion of contact between the biomaterial and biological medium (cell, tissue, fluid,,). The underlying concept of biocompatibility makes the interface between biomaterial and biological medium a privileged zone of interest. In this paper, we would like to give an exhaustive view of how ion beams techniques can contribute to a better understanding of such interface taking several examples dealing with bone tissue substitution. After a short presentation of ion beams techniques the paper will focus on PIXE/RBS spectroscopies and will give the basics of these coupled technique. Three examples will then be presented to illustrate the interest of these techniques to study biomaterials/biological interactions. The first example deals with metallic alloys based joint prostheses. The ionic release from the prosthesis and the wear behavior of total knee prostheses will be presented. In the last two examples, bioactive materials will be studied. The common characteristic of bioactive ceramics is the kinetic modification of their surface upon interaction which is ideally monitored by PIXE chemical mapping. The second example will review the benefit of using PIXE/RBS technique to study the effect of doping of bioactive glasses on the very first steps involved in the bioactivity mechanisms like dissolution, ionic release, and biomineralization onto the surface of the glasses. Finally, protein delivery systems based upon mesoporous hydroxyapatites will be studied. Chemical mapping allowing the quantitative determination of protein distribution inside the HAp grains will be presented for the first time. [source]

    Proteolytically Degradable Photo-Polymerized Hydrogels Made From PEG,Fibrinogen Adducts,

    Daniel Dikovsky
    Abstract We develop a biomaterial based on protein,polymer conjugates where poly(ethylene glycol) (PEG) polymer chains are covalently linked to multiple thiols on denatured fibrinogen. We hypothesize that conjugation of large diacrylate-functionalized linear PEG chains to fibrinogen could govern the molecular architecture of the polymer network via a unique protein,polymer interaction. The hypothesis is explored using carefully designed shear rheometry and swelling experiments of the hydrogels and their precursor PEG/fibrinogen conjugate solutions. The physical properties of non-cross-linked and UV cross-linked PEGylated fibrinogen having PEG molecular weights ranging from 10 to 20,kDa are specifically investigated. Attaching multiple hydrophilic, functionalized PEG chains to the denatured fibrinogen solubilizes the denatured protein and enables a rapid free-radical polymerization cross-linking reaction in the hydrogel precursor solution. As expected, the conjugated protein-polymer macromolecular complexes act to mediate the interactions between radicals and unsaturated bonds during the free-radical polymerization reaction, when compared to control PEG hydrogels. Accordingly, the cross-linking kinetics and stiffness of the cross-linked hydrogel are highly influenced by the protein,polymer conjugate architecture and molecular entanglements arising from hydrophobic/hydrophilic interactions and steric hindrances. The proteolytic degradation products of the protein,polymer conjugates proves to be were different from those of the non-conjugated denatured protein degradation products, indicating that steric hindrances may alter the proteolytic susceptibility of the PEG,protein adduct. A more complete understanding of the molecular complexities associated with this type of protein-polymer conjugation can help to identify the full potential of a biomaterial that combines the advantages of synthetic polymers and bioactive proteins. [source]

    Construction of Polyethyleneimine-,-cyclodextrin/pDNA Multilayer Structure for Improved In Situ Gene Transfection,

    Yan Hu
    This study reports in situ gene delivery from gene-functionalized poly(D,L -lactic acid) (PDLLA, Mw of around 2.0,×,105,g,mol,1) films, which were constructed via layer-by-layer (LbL) assembly technique with low molecular weight polyethylenimine-,-cyclodextrin (PEI-CD) conjugate and plasmid DNA (pDNA). PEI-CD was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR), respectively. The buildup of multilayered PEI-CD/pDNA pairs onto PDLLA films was monitored with contact angle measurements and UV,Vis spectrometer, respectively. A sustained release of pDNA from multilayered films was observed for 28,h. The mechanism of in situ gene delivery on PDLLA film was investigated in this study as well. Spherical PEI-CD/pDNA complexes were formed and released following the deconstruction of multilayered films, which was confirmed by transmission electron microscopy (TEM) and gel electrophoresis, respectively. Surface mediated in situ gene transfection was achieved when culturing hepatoma G2 (HepG2) and human embryonic kidney 293 (HEK293) onto PEI-CD/pDNA multilayered films. Furthermore, PEI-CD improved the gene transfection efficiency when compared with that of PEI. Such gene-functionalized biomaterial reported here has potential application in tissue engineering and implant technology. [source]

    Structural Evolution and Copper-Ion Release Behavior of Cu-pHEMA Hybrids Synthesized In Situ,

    Yen-Yu Liu
    Abstract A novel Cu-pHEMA hybrid was successfully prepared by in situ photopolymerization of 2-hydroxyethyl methacrylate (HEMA) monomer in the presence of Cu(II) copper ions, following an in situ chemical reduction. Experimental observations indicate that intermolecular interactions such as the coupling force and hydrogen bonding between the Cu and the hydroxyl groups further stabilize the hybrid structure to a considerable extent. Localization of the metallic copper particles within the pHEMA network structure as a result of those intermolecular interactions gives rise to the formation of discretely distributed nanocrystallites with particle sizes ranging from 5 to 25,nm in diameter. A crystallographic change of the Cu nanophase from an amorphous-like to a crystalline structure is observed as the H2O:HEMA molar ratio increases, upon synthesis, accompanied with an increase in the particle size. A relatively slow and sustained release of the Cu (in the form of cupric ions) from the hybrids was measured for a time period of about 10 days, which also illustrates a Cu(II)-induced proliferation of the endothelial cells over a relatively small range of release rate of the Cu from the hybrids. Such a new type of Cu-loaded hybrid hydrogel is expected to be compatible and may be considered as a candidate biomaterial for biomedical/therapeutic uses. [source]

    Antioxidant Activity of Degradable Polymer Poly(trolox ester) to Suppress Oxidative Stress Injury in the Cells

    Paritosh P. Wattamwar
    Abstract Oxidative stress is a pathological condition that has been implicated as a central player in a variety of diseases, including vascular and neurodegenerative diseases. More recently, oxidative stress has also been shown to be involved in the biological incompatibility of many materials, especially at the nanoscale. As such, there is a critical need for new biomaterials that can inhibit this response, improving the compatibility of medical devices. In this work, trolox, a synthetic antioxidant and water-soluble analogue of Vitamin E, is polymerized to form an oxidation active polymer as a new class of biomaterial. Synthesized poly(trolox ester) polymers were formulated into nanoparticles using a single emulsion technique, and their size was controlled by changing the polymer concentration in the organic solvent. Nanoparticle cytotoxicity, protective effects against cellular oxidative stress, and degradation kinetics were all evaluated. Poly(trolox ester) nanoparticles were found to have little to no cytotoxicity and were capable of suppressing cellular oxidative stress induced by cobalt nanoparticles. In vitro degradation studies of poly(trolox ester) nanoparticles indicate that the antioxidant activity of nanoparticles was derived from its enzymatic degradation to release active antioxidants. [source]

    Enzyme-Responsive Hydrogels: Dynamic, 3D-Pattern Formation Within Enzyme-Responsive Hydrogels (Adv. Mater.

    ADVANCED MATERIALS, Issue 41 2009
    On p. 4148, Sarah Heilshorn and Karin Straley demonstrate the design of a family of adaptive protein polymers with highly tunable and predictable degradation rates suitable for complex tissue-engineering applications. The cover image shows fluorescently labeled neurons grow and extend neurites on a protein-engineered biomaterial. Enzymes secreted by the neurons trigger selective degradation of specific regions of the biomaterial, allowing dynamic 3D patterns to emerge over time. Microscope images were acquired by Karin Straley. Digital art by Chelsea Castillo. [source]

    Covalent Attachment of Low Molecular Weight Poly(ethylene imine) Improves Tat Peptide Mediated Gene Delivery,

    ADVANCED MATERIALS, Issue 16 2006
    F. Alexis
    A polymer-peptide hybrid biomaterial synthesized by coupling poly(ethylene imine) directly to resin-supported Tat peptide takes advantage of the unique features associated with the two original cationic materials and functions as a novel gene-delivery vector with good biocompatibility. The figure shows cells transfected with green fluorescent protein (GFP) using complexes of the polymer-peptide hybrid and GFP (scale bar: 100,,m). [source]

    The biology of vernix caseosa

    S. B. Hoath
    Synopsis The biology and physical properties of the uniquely human skin cream ,vernix caseosa' are discussed. This material coats the foetal skin surface during the last trimester of gestation and provides multiple beneficial functions for the foetus and newborn infant. Vernix has a complex structure similar to stratum corneum but lacks lipid lamellae and is more plastic due to the absence of desmosomal constraints. In utero, vernix is made in part by foetal sebaceous glands, interacts with pulmonary surfactant, detaches into the amniotic fluid, and is swallowed by the foetus. At the time of birth, vernix has a remarkably constant water content approximating 80%. Postnatally, vernix is simultaneously a cleanser, a moisturizer, an anti-infective, and an anti-oxidant. Vernix facilitates acid mantle development and supports normal bacterial colonization. Its hydrated cellular structure and unusual lipid composition provide a ,best' solution for the needs of the foetus and newborn, not least of which is the attraction of caregivers. Vernix is an important natural biomaterial of potential interest to cosmetic scientists, and other disciplines involved in product development and therapies targeting the complex interface between the stratum corneum and a changing terrestrial environment. Résumé La biologie et les propriétés physiques de la crème de peau exclusivement humaine ,Vernix caseosa « sont discutées. Ce matériau couvre la surface de la peau foetale pendant le dernier trimestre de gestation et remplit des fonctions avantageuses multiples pour le foetus et le nouveau-né. Le Vernix a une structure complexe semblable au stratum corneum, mais manque de lamelles lipidiques et est plus plastique en raison de l'absence de contraintes desmosomales. In utero, le Vernix est constitué en partie par des glandes sébacées foetales, il interagit avec le surfactant pulmonaire, il se détache dans le liquide amniotique et est avalé par le foetus. Au moment de la naissance, le Vernix a une teneur remarquablement constante en eau de l'ordre de 80%. Après la naissance, le Vernix devient simultanément un produit de lavage, un produit hydratant, un anti-infectieux et un anti-oxydant. Le Vernix facilite le développement du manteau acide et soutient la colonisation bactérienne normale. Sa structure cellulaire hydratée et sa composition en lipide inhabituelle en font ,une des meilleures » solutions pour les besoins du foetus et du nouveau-né, à laquelle le personnel soignant n'attache pas la moindre importance. Le Vernix est un biomatériau naturel important potentiellement intéressant pour les scientifiques cosméticiens et pour les autres disciplines impliquées dans le développement de produits et de thérapies visant l'interface complexe entre le stratum corneum et un environnement terrestre changeant. [source]

    Rigid, Self-Assembled Hydrogel Composed of a Modified Aromatic Dipeptide,

    ADVANCED MATERIALS, Issue 11 2006
    A. Mahler
    A simple dipeptide self-assembles into a biocompatible hydrogel (see figure and inside cover). This novel biomaterial is extremely simple to prepare and has a remarkable rigidity. It is very stable under extreme conditions, can be injected, and can be shaped according to the vessel it has been assembled in. The hydrogel allows a wide variety of possible biomedical applications including tissue engineering, axonal regeneration, and controlled drug release. [source]

    A Covalently Interconnected Phosphazene,Silicate Hybrid Network: Synthesis, Characterization, and Hydrogel Diffusion-Related Application,

    ADVANCED MATERIALS, Issue 6 2003
    Y. Chang
    Sol,gel precursors of poly[bis(methoxyethoxyethoxy)phosphazene] have been synthesized by incorporating triethoxysilane in the polymer side groups. Studies of the water-swelling (see Figure, dry left, water-swollen, right) behavior and dye-release of the hybrid network indicate that the polyphosphazene,silicate network has potential as a biomaterial and for use in both passive and responsive membranes. [source]

    Oxycellulose: Significant characteristics in relation to its pharmaceutical and medical applications

    Bajerová Martina
    Abstract As a biomaterial, cellulose can be converted into a wide range of derivatives with desired properties for a variety of medical, biomedical, and pharmaceutical applications. The oxidation of cellulose yields oxidized cellulose (OC, oxycellulose, 6-carboxycellulose). OC represents an important class of biocompatible and bioresorbable polymers. In vivo bioabsorption of OC occurs via chemical depolymerization and enzymatic hydrolysis. Despite the fact OC is well established as a hemostatic agent and is widely used in a clinical practice, it still attracts a great interest and its new applications, especially pharmaceutical, are investigated. The present review is focused on characterization of OC's physical and chemical properties. Its synthesis and mechanisms involved in its in vivo and in vitro biodegradation are discussed. Medical and biomedical applications of OC are summarized, and especially its hemostatic, enterosorbent, and wound-healing properties are described. In addition to these applications, OC could be used as a pharmaceutical excipient in solid (e.g., tablets, microparticles), semisolid (e.g., gels), as well as liquid (e.g., suspensions) dosage forms. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:199,208, 2009; Published online in Wiley InterScience ( DOI 10.1002/adv.20161 [source]

    Modeling of transport phenomena and melting kinetics of starch in a co-rotating twin-screw extruder,

    Lijun Wang
    A mathematical model was developed to simulate fluid flow, heat transfer, and melting kinetics of starch in a co-rotating intermeshing twin-screw extruder (TSE). The partial differential equations governing the transport phenomena of the biomaterial in the extruder were solved by a finite element scheme. For validating the model, the predicted product pressure, bulk temperature at the entrance of the die, and minimum residence time of the biomaterial in the extruder were compared with experimental data. Standard errors of product pressure, bulk temperature at the die entrance, and minimum residence time were about 8.8, 2.8, and 17.3%. Simulations were carried out to investigate profiles of product pressure, bulk temperature, and melt fraction within the extruder during extrusion. © 2006 Wiley Periodicals, Inc. Adv Polym Techn 25: 22,40, 2006; Published online in Wiley InterScience ( DOI 10.1002/adv.20055 [source]

    Preparation and cytocompatibility of chitosan-modified polylactide

    Yumei Xiao
    Abstract Chitosan-modified PLA (CMPLA) was fabricated to improve cytocompatibility of polylactide (PLA). PMAA-grafted PLA (PMAA-PLA) was obtained through ,-methacrylic acid (MAA) grafted polymerization on PLA surface with photooxidization and UV irradiation. Steady PMAA-PLA microparticle suspension with an average size as 172.8 ± 3.6 nm and zeta potential as ,95.0 ± 0.6 mV was prepared through solvent volatilization. By static electricity interaction and other interactions between PMAA-PLA microsparticles and chitosan molecules, CMPLA was obtained. FTIR, XPS, SEM, and zeta potential analyses indicated that CMPLA was modified with chitosan molecules uniformly. Compared with the PLA control, CMPLA adapted to supporting the attachment and proliferation of L929 cells better. The obtained CMPLA was expected to be used as perfect biomaterial for tissue regeneration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

    Polysaccharide-based artificial extracellular matrix: Preparation and characterization of three-dimensional, macroporous chitosan, and heparin composite scaffold

    Shu-Huei Yu
    Abstract Scaffold-guided tissue engineering based on synthetic and natural occurring polymers has gained many interests in recent year. In this study, the development of a chitosan-heparin artificial extracellular matrix (AECM) is reported. Three-dimensional, macroporous composite AECMs composed of heparin (Hep) and chitosan (Chito) were prepared by an interpolyelectrolyte complex/lyophilization method. The Chito-Hep composite AECMs were, respectively, crosslinked with glutaraldehyde, as well as cocrosslinked with N,N -(3-dimethylaminopropyl)- N,-ethyl carbodiimide (EDC/NHS) and N -hydroxysuccinimide (NHS). The crosslinking reactions were examined by FT-IR analysis. In physiological buffer solution (PBS), the EDC/NHS-crosslinked Chito-Hep composite AECM showed a relative lower water retention ratio than its glutaraldehyde-crosslinked counterparts. The EDC/NHS-crosslinked Chito-Hep composite AECMs showed excellent biocompatibility, according to the results of the in vitro cytotoxic test. This result suggested that the EDC/NHS-crosslinked Chito-Hep composite AECMs might be a potential biomaterial for scaffold-guided tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

    Ageing of soft thermoplastic starch with high glycerol content

    Rui Shi
    Abstract In this study, a soft and thermoplastic starch with an improved ageing-resistant property was prepared by melt blending method for a biodegradable biomaterial. The glycerol content varies from 30 to 60 wt %. The aging temperature and humidity of the glycerol-plasticized thermoplastic starch (GTPS) was 37°C and 50 ± 5 RH %, respectively. The retrogradation was characterized by X-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), Fourier transform infrared (FTIR), and the stress-strain mechanical properties. The XRD results suggest that high content of glycerol promotes the formation of single helix structure of V-type, but inhibits double helix structure of B-type. Changing of the tan ,, storage modules (E,), and the glass transition temperatures as a function of glycerol content and ageing time was detected by DMTA. FTIR result shows that the shifting speed of the peak of hydroxyl group stretching fell as the glycerol content increased. The glycerol content has no obvious effect on the mechanical properties when it is high enough. Results from all characterizations demonstrate that the ageing speed is closely relative to the plasticizers content. The higher content of glycerol possesses an obviously inhibitory effect on the ageing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 574,586, 2007 [source]

    Addition of nimesulide to small intestinal submucosa biomaterial inhibits postsurgical adhesiogenesis in rats

    Mark A. Suckow
    Abstract Adhesion formation is a common complication in abdominal surgery with incidence as high as 93% and small bowel obstruction a common complication. Because the extracellular matrix material, small intestinal submucosa (SIS), is commonly used in various surgical procedures, methods to inhibit adhesiogenesis are of great interest. This study was undertaken to determine if incorporation of nimesulide (NM), a selective cyclooxygenase (COX)-2 inhibitor, could reduce the extent and tenacity of intraabdominal adhesion formation associated with SIS implantation. Female Sprague,Dawley rats underwent a cecal abrasion surgical procedure to induce adhesiogenesis. Rats were either left untreated or treated by direct application over the injured cecum with polypropylene mesh (PPM); SIS; SIS containing a low dose of NM; or SIS containing a high dose of NM. Rats were euthanized 21 days later, and adhesion extent and tenacity were evaluated using standard scales (0 = minimal adhesiogenesis; 4 = severe adhesiogenesis). Addition of NM to SIS resulted in a significant (p < 0.05) reduction in adhesion extent and in a similar reduction in adhesion tenacity for SIS containing a low dose of NM. Adhesions typically extended from the abraded cecal surface to the body wall and were characterized histologically by fibrous tissue adherent to the cecal wall. In conclusion, addition of the nonsteroidal anti-inflammatory, COX-2 selective drug, NM, to SIS attenuates adhesion extent and tenacity when compared with surgical placement of SIS or PPM alone. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [source]

    Calcium phosphate-based coatings on titanium and its alloys

    R. Narayanan
    Abstract Use of titanium as biomaterial is possible because of its very favorable biocompatibility with living tissue. Titanium implants having calcium phosphate coatings on their surface show good fixation to the bone. This review covers briefly the requirements of typical biomaterials and narrowly focuses on the works on titanium. Calcium phosphate ceramics for use in implants are introduced and various methods of producing calcium phosphate coating on titanium substrates are elaborated. Advantages and disadvantages of each type of coating from the view point of process simplicity, cost-effectiveness, stability of the coatings, coating integration with the bone, cell behavior, and so forth are highlighted. Taking into account all these factors, the efficient method(s) of producing these coatings are indicated finally. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source]

    Control of pore structure and size in freeze-dried collagen sponges

    Heike Schoof
    Abstract Because of many suitable properties, collagen sponges are used as an acellular implant or a biomaterial in the field of tissue engineering. Generally, the inner three-dimensional structure of the sponges influences the behavior of cells. To investigate this influence, it is necessary to develop a process to produce sponges with a defined, adjustable, and homogeneous pore structure. Collagen sponges can be produced by freeze-drying of collagen suspensions. The pore structure of the freeze-dried sponges mirrors the ice-crystal morphology after freezing. In industrial production, the collagen suspensions are solidified under time- and space-dependent freezing conditions, resulting in an inhomogeneous pore structure. In this investigation, unidirectional solidification was applied during the freezing process to produce collagen sponges with a homogeneous pore structure. Using this technique the entire sample can be solidified under thermally constant freezing conditions. The ice-crystal morphology and size can be adjusted by varying the solute concentration in the collagen suspension. Collagen sponges with a very uniform and defined pore structure can be produced. Furthermore, the pore size can be adjusted between 20,40 ,m. The thickness of the sponges prepared during this research was 10 mm. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 352,357, 2001 [source]

    Evaluation of processed bovine cancellous bone matrix seeded with syngenic osteoblasts in a critical size calvarial defect rat model

    U. Kneser
    Abstract Introduction: Biologic bone substitutes may offer alternatives to bone grafting procedures. The aim of this study was to evaluate a preformed bone substitute based on processed bovine cancellous bone (PBCB) with or without osteogenic cells in a critical size calvarial defect rat model. Methods: Discs of PBCB (Tutobone®) were seeded with second passage fibrin gel-immobilized syngenic osteoblasts (group A, n = 40). Cell-free matrices (group B, n = 28) and untreated defects (group C; n=28) served as controls. Specimens were explanted between day 0 and 4 months after implantation and were subjected to histological and morphometric evaluation. Results: At 1 month, bone formation was limited to small peripheral areas. At 2 and 4 months, significant bone formation, matrix resorption as well as integration of the implants was evident in groups A and B. In group C no significant regeneration of the defects was observed. Morphometric analysis did not disclose differences in bone formation in matrices from groups A and B. Carboxyfluorescine-Diacetate-Succinimidylester (CFDA) labeling demonstrated low survival rates of transplanted cells. Discussion: Osteoblasts seeded into PBCB matrix display a differentiated phenotype following a 14 days cell culture period. Lack of initial vascularization may explain the absence of added osteogenicity in constructs from group A in comparison to group B. PBCB is well integrated and represents even without osteogenic cells a promising biomaterial for reconstruction of critical size calvarial bone defects. [source]

    Effect of systemic parathyroid hormone (1,34) and a , -tricalcium phosphate biomaterial on local bone formation in a critical-size rat calvarial defect model

    Jonathan I. Yun
    Yun JI, Wikesjö UME, Borke JL, Bisch FC, Lewis JE, Herold RW, Swiec GD, Wood JC, McPherson III JC. Effect of systemic parathyroid hormone (1,34) and a ,-tricalcium phosphate biomaterial on local bone formation in a critical-size rat calvarial defect model. J Clin Periodontol 2010; 37: 419,426 doi: 10.1111/j.1600-051X.2010.01547.x Abstract Objective: The objective of this study was to evaluate local bone formation following systemic administration of parathyroid hormone (1,34) (PTH), a surgically implanted synthetic , -tricalcium phosphate (, -TCP) bone biomaterial serving as a matrix to support new bone formation. Materials and Methods: Critical-size, 8 mm, calvarial through-and-through osteotomy defects were surgically created in 100 adult male Sprague,Dawley rats. The animals were randomized into five groups of 20 animals each to receive one of the following treatments: PTH (15 ,g PTH/kg/day; subcutaneously), PTH/, -TCP, , -TCP, or particulate human demineralized freeze-dried bone (DFDB), and sham-surgery controls. Ten animals/group were euthanized at 4 and 8 weeks post-surgery for radiographic and histometric analysis. Results: The histometric analysis showed that systemic PTH significantly enhanced local bone formation, bone fill averaging (±SE) 32.2±4.0% compared with PTH/, -TCP (15.7±2.4%), , -TCP (12.5±2.3%), DFDB (14.5±2.3%), and sham-surgery control (10.0±1.5%) at 4 weeks (p<0.014). Systemic PTH showed significantly enhanced bone formation (41.5±4.0%) compared with PTH/, -TCP (22.4±3.0%), , -TCP (21.3±4.4%), and with the sham-surgery control (23.8±4.2%) at 8 weeks (p<0.025). The DFDB group showed significantly increased bone formation from 4 (14.5±2.3%) to 8 weeks (32.0±3.2%) (p<0.006). The PTH/, -TCP and , -TCP groups both showed limited biomaterials resorption. The radiographic analysis was not diagnostic to distinguish local bone formation from the radiopaque , -TCP biomaterial. Conclusions: Systemic administration of PTH significantly stimulates local bone formation. Bone formation was significantly limited by the , -TCP biomaterial. [source]

    Orthodontic movement after periodontal regeneration of class II furcation: a pilot study in dogs

    Vanessa Camila Da Silva
    Abstract Purpose: The effect of orthodontic movement on the periodontal tissues of maxillary second pre-molars, after regenerative treatment for class II furcations, was evaluated in four mongrel dogs. Material and Methods: Class II furcation lesions were created. After 75 days they were treated with bovine bone mineral matrix and guided tissue regeneration with absorbable membrane. After 2 months of daily plaque control, each of the dog's furcation pre-molars was randomly assigned to a test or control group. Orthodontic appliances were placed on both sides of the maxilla using third pre-molars and canines as anchorages. In the test group, bodily orthodontic movement of the second pre-molars was performed in the mesial direction for 3 months while control pre-molars remained unmoved. The dogs were sacrificed for histometric and histologic analyses. Results: There were no statistically significant differences between the two groups in total bone and biomaterial areas or linear extension of periodontal regeneration on the radicular surfaces. In the test group, however, there was a tendency to a greater quantity of bone and a lesser quantity of biomaterial. Conclusion: The orthodontic movement was not pre-judicial to the results obtained with the regenerative periodontal treatment. [source]