Coaxially electrospun heparin-eluting scaffolds for vascular graft application

The use of electrospun scaffolds for small diameter vascular grafts ( 0.9 MPa, maximum strain > 100 %, suture retention > 2.4 N) or within groups between the longitudinal and circumferential tensile properties. After 6 weeks of in vitro degradation, all groups exhibited similar mechanical losses of approximately 40 % in ultimate tensile stress and 80 % in maximum elongation in circumferential and longitudinal directions. The smaller vascular grafts had burst pressures superior to native vasculature and compliances approximating those of healthy arteries. Thermal analyses (DSC) of the different groups showed similar thermograms with little intergroup variation and indicated that the electrospinning process did not unduly affect the thermal properties or crystallinity, of DP30. There was also no major variations in thermograms of degraded samples. Blend electrospun scaffolds showed the expected initial burst release of HepTBA (47.7 %, 3 days) followed by a sustained release (56.1 %, 6 weeks). Coaxially incorporated HepNa+ also exhibited initial burst release (67.5-69.7 %, 3 days) for both the low and high heparin content groups followed by improved sustained release (81.9 - 97.7%, 6 weeks). Coaxial incorporation had a 2× higher heparin encapsulation efficiency than blend incorporation (approaching 100 %). Heparin, post-TBA-modification, did not fully retain its antithrombotic properties (54.9 % reduction), which was further reduced after incorporation and release (24.2 % reduction). HepNa+ , however, retained its full antithrombotic activity post coaxial incorporation and elution. Coaxial electrospinning of heparin in DP30 shows potential for producing small diameter vascular grafts with mechanical properties comparable to small blood vessels. Although some initial burst release occurred, the sustained release over 6 weeks, incorporation of heparin without the need for modification at improved efficiency, and the retained activity of the heparin after electrospinning incorporation and elution; holds promise for vascular graft applications. Future work should aim for the production of continuous cores within fibre morphology and evaluating graft performance in an in vivo model to determine whether an appropriate and sufficient amount of heparin has been included to affect the desired response

Tailoring bombyx mori silk as multifuctional material for advanced applications.

288 p.Materials support human development. Among the available materials, polymers are nowadays essential and practically omnipresent because of their unrivalled properties. Unfortunately, polymers are synthesized from oil, and they tend to accumulate in nature, which represents a serious environmental impact.To minimize these damages, materials science suggests replacing synthetic polymers with bio-based materials. To promote the use of these more sustainable materials, the objective of the work has been to demonstrate the real applicability of bio-based materials, and more specifically Silk Fibroin (SF), a protein obtained from Bombyx mori (silkworm) cocoons. This protein displays unique physical-chemical properties that make it an interesting substrate for the development of new materials with advanced properties.Two main fields of application have been selected in this work for SF: i) electronics (active composites for sensors and actuators) and ii) porous structures for biomedicine, energy, and environment.For electronics, SF has been combined with i) carbon nanotubes (CNT) to obtain force sensors with piezoresistive responses (PR) of ~ 4 MPa-1 at pressures of 0.11 MPa; ii) with silver nanowires (SNW) to obtain PR of 26 GPa-1 when the pressure is between 0.2 and 0.4 MPa. Also, SF/SNW nanocomposites show optical transparency at SNW loads above 3%; iii) with cobalt ferrite nanoparticles (CFO) to obtain magnetic actuators with a magnetization value of ~ 10 emu·g¿1 and coercivity of almost 4 kOe, (20 wt. % CFO); and iv) with ionic liquids (IL) to obtain bending actuators with bending responses of ~ 0.5 by applying low voltages (3-5 V).SF has been processed also for the development of porous structures by i) electrospinning, to obtain scaffolds that when are combined with CFO particles, stimulate the bone cells development; ii) by salt leaching; to obtain Li-ion battery separators that lead to battery performance of 89,3 y 131,3 mAh·g¿1, for 2C and C/8 cycles respectively and iii) by gas foaming, gelation and freeze-drying, to obtain samples with porosity values above 94% and aqueous Cr adsorption capacities up to 3 mg/g.Bc Materials: Basque Center for materials applications & nanostructure

Tailoring bombyx mori silk as multifuctional material for advanced applications.

288 p.Materials support human development. Among the available materials, polymers are nowadays essential and practically omnipresent because of their unrivalled properties. Unfortunately, polymers are synthesized from oil, and they tend to accumulate in nature, which represents a serious environmental impact.To minimize these damages, materials science suggests replacing synthetic polymers with bio-based materials. To promote the use of these more sustainable materials, the objective of the work has been to demonstrate the real applicability of bio-based materials, and more specifically Silk Fibroin (SF), a protein obtained from Bombyx mori (silkworm) cocoons. This protein displays unique physical-chemical properties that make it an interesting substrate for the development of new materials with advanced properties.Two main fields of application have been selected in this work for SF: i) electronics (active composites for sensors and actuators) and ii) porous structures for biomedicine, energy, and environment.For electronics, SF has been combined with i) carbon nanotubes (CNT) to obtain force sensors with piezoresistive responses (PR) of ~ 4 MPa-1 at pressures of 0.11 MPa; ii) with silver nanowires (SNW) to obtain PR of 26 GPa-1 when the pressure is between 0.2 and 0.4 MPa. Also, SF/SNW nanocomposites show optical transparency at SNW loads above 3%; iii) with cobalt ferrite nanoparticles (CFO) to obtain magnetic actuators with a magnetization value of ~ 10 emu·g¿1 and coercivity of almost 4 kOe, (20 wt. % CFO); and iv) with ionic liquids (IL) to obtain bending actuators with bending responses of ~ 0.5 by applying low voltages (3-5 V).SF has been processed also for the development of porous structures by i) electrospinning, to obtain scaffolds that when are combined with CFO particles, stimulate the bone cells development; ii) by salt leaching; to obtain Li-ion battery separators that lead to battery performance of 89,3 y 131,3 mAh·g¿1, for 2C and C/8 cycles respectively and iii) by gas foaming, gelation and freeze-drying, to obtain samples with porosity values above 94% and aqueous Cr adsorption capacities up to 3 mg/g.Bc Materials: Basque Center for materials applications & nanostructure

21st Century Nanostructured Materials

Nanostructured materials (NMs) are attracting interest as low-dimensional materials in the high-tech era of the 21st century. Recently, nanomaterials have experienced breakthroughs in synthesis and industrial and biomedical applications. This book presents recent achievements related to NMs such as graphene, carbon nanotubes, plasmonic materials, metal nanowires, metal oxides, nanoparticles, metamaterials, nanofibers, and nanocomposites, along with their physical and chemical aspects. Additionally, the book discusses the potential uses of these nanomaterials in photodetectors, transistors, quantum technology, chemical sensors, energy storage, silk fibroin, composites, drug delivery, tissue engineering, and sustainable agriculture and environmental applications

Nanostructural Materials with Rare Earth Ions: Synthesis, Physicochemical Characterization, Modification and Applications

This Special Issue of "Nanostructural Materials with Rare Earth Ions: Synthesis, Physicochemical Characterization, Modification and Applications" is related to studies of nanometer-sized materials doped and co-doped with rare earth ions and the creation of periodically ordered nanostructures based on single nanoparticles. A small particle size implies a high sensitivity and selectivity. These new effects and possibilities are mainly due to the quantum effects resulting from the increasing ratio of surface-to-volume atoms in low-dimensional systems. An important factor in this context is the design and fabrication of nanocomponents displaying new functionalities and characteristics for the improvement of existing materials, including photonic materials, conductive materials, polymers and biocomposites. With this concept in mind, the aim of the Special Issue is to publish research on innovative materials and their applications.Topics to be covered in this Special Issue include, but are not limited to, the following: Technology and applications of nanomaterials with rare earth ions; Advanced physicochemical properties, characterization and modification of nanomaterials with rare earth ions; Novel active materials, especially organic and inorganic materials, nanocrystalline materials, nanoceramics doped and co-doped with rare-earth ions with bio-related and emerging applications; Magnetic properties of nano-sized rare-earth compounds; Applications of nano-sized rare-earth-doped and co-doped optical materials

Dental Implant Systems

Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities

Progenitor cells in auricular cartilage demonstrate promising cartilage regenerative potential in 3D hydrogel culture

The reconstruction of auricular deformities is a very challenging surgical procedure that could benefit from a tissue engineering approach. Nevertheless, a major obstacle is presented by the acquisition of sufficient amounts of autologous cells to create a cartilage construct the size of the human ear. Extensively expanded chondrocytes are unable to retain their phenotype, while bone marrow-derived mesenchymal stromal cells (MSC) show endochondral terminal differentiation by formation of a calcified matrix. The identification of tissue-specific progenitor cells in auricular cartilage, which can be expanded to high numbers without loss of cartilage phenotype, has great prospects for cartilage regeneration of larger constructs. This study investigates the largely unexplored potential of auricular progenitor cells for cartilage tissue engineering in 3D hydrogels

Defense Technical Information Center thesaurus

This DTIC Thesaurus provides a basic multidisciplinary subject term vocabulary used by DTIC to index and retrieve scientific and technical information from its various data bases and to aid DTIC`s users in their information storage and retrieval operations. It includes an alphabetical posting term display, a hierarchy display, and a Keywork Out of Context (KWOC) display