1180 results found
Alonso Frank M, Meltzer C, Braunschweig B, et al., 2017, Functionalization of steel surfaces with organic acids: Influence on wetting and corrosion behavior, Applied Surface Science, Vol: 404, Pages: 326-333, ISSN: 0169-4332
© 2017 Elsevier B.V.Self-assembled monolayers (SAMs) have been used to tailor surface properties of different metal surfaces. Typically SAMs can be bound to surface hydroxyls of a thin oxide layer that forms on the surface of a less noble metal and dominates its properties. The effects of SAMs with different anchoring groups and chain lengths regarding wettability, corrosion resistance and homogeneity of the layer were studied in detail. Alkyl carbonic and phosphonic acids were selected to create a hydrophobic layer on the surface of stainless steel ASIS 316L and on carbon steel N80. SAMs were formed by dip-coating of the samples in an organic acid ethanolic solution. Sum frequency generation (SFG) analysis together with contact angle and electrochemical measurements were carried out to explore correlations between tailored wettability, corrosion resistance, and layer homogeneity on one side, and the chain length, anchor group, concentration and immersion time on the other side. The homogeneity of the layers as well as the resulting surface hydrophobicity increased with an increase of the immersion time, the contact angle reached a maximum (ca. 120°) for an immersion time of approximately 2 days.
Araújo M, Viveiros R, Philippart A, et al., 2017, Bioactivity, mechanical properties and drug delivery ability of bioactive glass-ceramic scaffolds coated with a natural-derived polymer., Mater Sci Eng C Mater Biol Appl, Vol: 77, Pages: 342-351
In this work, hybrid melanin-coated bioactive glass-ceramic multifunctional scaffolds were developed and characterized in terms of mechanical strength, in vitro bioactivity in simulated body fluid (SBF) and ability to load ibuprofen. The coated scaffolds exhibited an accelerated bioactivity in comparison with the uncoated ones, being able of developing hydroxyapatite-like crystals after 7days soaking in simulated body fluid (SBF). Besides its positive influence on the scaffolds bioactivity, the melanin coating was able to enhance their mechanical properties, increasing the initial compressive strength by a factor of >2.5. Furthermore, ibuprofen was successfully loaded on this coating, allowing a controlled drug release of the anti-inflammatory agent.
Bejarano J, Detsch R, Boccaccini AR, et al., 2017, PDLLA scaffolds with Cu- and Zn-doped bioactive glasses having multifunctional properties for bone regeneration., J Biomed Mater Res A, Vol: 105, Pages: 746-756
Novel multifunctional scaffolds for bone regeneration can be developed by incorporation of bioactive glasses (BG) doped with therapeutic and antibacterial metal ions, such as copper (Cu) and zinc (Zn), into a biodegradable polymer. In this context, porous composite materials of biodegradable poly(d, l-lactide) (PDLLA) mixed with sol-gel BG of chemical composition 60SiO2 ; 25CaO; 11Na2 O; and 4P2 O5 (mol %) doped with either 1 mol % of CuO or ZnO, and with both metals, were prepared. The cytocompatibility of the scaffolds on bone marrow stromal cells (ST-2) depended on both, the amount of glass filler and the concentration of metal ion, as evaluated by lactate dehydrogenase (LDH) activity, cell viability (water-soluble tetrazolium salt [WST-8]), and by cell morphology (scanning electron microscopy [SEM]) tests. In particular, scaffolds having a filler content of 10 wt % showed the highest cytocompatibility. In addition, compared to the neat polymer, the scaffolds containing Cu promoted the angiogenesis marker (Vascular endothelial growth factor concentration) to a larger extent while scaffolds containing Zn increased the osteogenesis marker (specific alkaline phosphatase-activity). Noteworthy, the scaffolds with both metal ions showed a combined effect on both properties. Cu- and Zn-doped glasses also provided higher antibacterial capacity to PDLLA-based scaffolds against methicillin-resistant S. aureus bacteria than undoped glass. In combination, our results showed that by a proper addition of Cu- and Zn-doped BG to a PDLLA matrix, multifunctional composite scaffolds with enhanced biological activity can be designed for bone tissue regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 746-756, 2017.
Bertolla L, Dlouhý I, Tatarko P, et al., 2017, Pressureless spark plasma–sintered Bioglass<sup>®</sup> 45S5 with enhanced mechanical properties and stress–induced new phase formation, Journal of the European Ceramic Society, Vol: 37, Pages: 2727-2736, ISSN: 0955-2219
© 2017 Elsevier LtdCommercial Bioglass® 45S5 powder was sintered using spark plasma sintering (SPS) technique without the assistance of mechanical pressure with heating and cooling rate of 100 °C/min, dwell temperature of 1050 °C and dwell time of 30 min. Such route enabled the production of samples exhibiting superior mechanical properties in comparison with Bioglass® sintered in furnace. In particular, flexural strength and fracture toughness reached values close to those of apatite-wollastonite bioceramics, already widely used in clinical applications. The residual stresses implemented by indentation promoted the formation of a new phase in samples sintered by SPS. Complementary use of Raman and energy dispersive spectroscopy (EDS) indicated the phase as sodium carbide and a formation mechanism was proposed.
Boccaccini AR, 2017, Editorial Note, Materials Letters, Vol: 197, ISSN: 0167-577X
Boccaccini AR, Brauer DS, Hupa L, 2017, Preface
Boccardi E, Ciraldo FE, Boccaccini AR, 2017, Bioactive glass-ceramic scaffolds: Processing and properties, MRS Bulletin, Vol: 42, Pages: 226-232, ISSN: 0883-7694
© 2017 Materials Research Society.Bioactive glasses and related bioactive glass-ceramics have been used for over three decades in biomedical applications such as bulk, particulate, or coatings materials. More recently, highly porous bioactive glass-ceramic scaffolds for bone-Tissue engineering have also been developed from selected compositions of bioactive glasses. Current bioactive glass-ceramic scaffolds are characterized by an open porous network, high bioactivity, and mechanical properties similar to those of trabecular bone. This article reviews the latest achievements in the development of porous bioactive glass-ceramics intended for bone-Tissue engineering applications, highlighting the fabrication technologies and scaffold properties. Improvements in the mechanical properties of bioactive glass-ceramic scaffolds exhibiting high bioactivity have been achieved by different approaches in the last 10 years. Relevant long-Term in vivo studies are required to confirm the suitability of such bioactive glass-ceramic scaffolds in clinical applications.
Cordero-Arias L, Boccaccini AR, 2017, Electrophoretic deposition of chondroitin sulfate-chitosan/bioactive glass composite coatings with multilayer design, Surface and Coatings Technology, Vol: 315, Pages: 417-425, ISSN: 0257-8972
© 2017 Elsevier B.V.Novel chondroitin sulfate (CS) based coatings were produced by electrophoretic deposition (EPD). CS was used as matrix and combined with bioactive glass (BG) particles to produce a series of bioactive composite coatings with potential for orthopedic and dental applications. Furthermore multilayer systems incorporating chitosan were designed and developed to tailor coating composition, bioactivity and degradation. Solutions and suspensions based on CS were developed, and their stability analyzed by means of ζ–potential measurements. EPD conditions (concentration, potential and deposition time) were investigated and determined for CS and BG/CS coatings, as well as for a variety of multilayer systems. Coating morphology, microstructure and composition were studied using SEM, XRD, FTIR spectroscopy and TG-DTA techniques which confirmed the formation of a variety of homogeneous CS based multilayered coatings. Finally, immersion test in simulated body fluid was carried out demonstrating the bioactive behavior of some of the new systems developed after 2 days of immersion. CS containing coatings are of interest for applications where the combined effects of CS and BG can lead to enhanced tissue regeneration effects.
Considerable research efforts have been devoted to zein-based biomaterials for tissue engineering and other biomedical applications over the past decade. The attention given to zein-based polymers is primarily attributed to their biocompatibility and biodegradability. However, due to the relatively low mechanical properties of these polymers, numerous inorganic compounds (e.g., hydroxyapatite, calcium phosphate, bioactive glasses, natural clays) have been considered in combination with zein to create composite materials in an attempt to enhance zein mechanical properties. Inorganic phases also positively impact on the hydrophilic properties of zein matrices inducing a suitable environment for cell attachment, spreading, and proliferation. This review covers available literature on zein and zein-based composite materials, with focus on the combination of zein with commonly used inorganic fillers for tissue engineering and drug delivery applications. An overview of the most recent advances in fabrication techniques for zein-based composites is presented and key applications areas and future developments in the field are highlighted. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1656-1665, 2017.
Dippold D, Cai A, Hardt M, et al., 2017, Novel approach towards aligned PCL-Collagen nanofibrous constructs from a benign solvent system., Mater Sci Eng C Mater Biol Appl, Vol: 72, Pages: 278-283
Under several conditions such as severe trauma skeletal muscle lack the ability to reorganize and the loss of muscle function is inevitable. The application of tissue engineered constructs is a promising approach in regenerative therapies for damaged muscular tissue. Therefore, the development of highly aligned scaffolds based on polycaprolactone (PCL) has been studied extensively. Nanofiber scaffolds containing collagen have mostly been fabricated via electrospinning using highly corrosive 1,1,1,3,3,3 hexafluoro-2-propanol (HFIP) so far. In this study, aligned Polycaprolactone-Collagen (PCL-Coll) biocomposite nanofibers were fabricated via electrospinning using environmentally benign diluted acetic acid (AcOH) as solvent. Furthermore, ultrasonic treatment was introduced to enhance the intrinsically weak solubility of PCL in AcOH. AcOH was diluted to an ideal concentration for electrospinning of 90%. The final solutions were spun at various conditions and collected with different collector setups in order to determine ideal processing conditions for the fabrication of highly aligned nanofibers.
Ege D, Duru I, Kamali AR, et al., 2017, Nitride, Zirconia, Alumina, and Carbide Coatings on Ti6Al4V Femoral Heads: Effect of Deposition Techniques on Mechanical and Tribological Properties, Advanced Engineering Materials, ISSN: 1438-1656
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Ti6Al4V has been extensively studied in orthopedic applications because of its biocompatibility, desirable mechanical strength, and fatigue resistance. A wide range of bioinert ceramics have been investigated to further develop the tribological and mechanical properties of Ti6Al4V for the production of potential femoral heads. However, an analysis of the literature indicates that the performance of the coatings produced has been inconsistent. In this review, for the first-time deposition techniques of the most widely studied bioinert ceramics namely nitrides, carbides, zirconia, and alumina on Ti6Al4V substrates and their relevant mechanical and tribological performance have been analyzed. Finally, graphene has also been suggested for use together with bioinert ceramics due to its excellent mechanical and physical properties for coating Ti6Al4V femoral heads.
Fiocco L, Elsayed H, Badocco D, et al., 2017, Direct ink writing of silica-bonded calcite scaffolds from preceramic polymers and fillers., Biofabrication, Vol: 9
Silica-bonded calcite scaffolds have been successfully 3D-printed by direct ink writing, starting from a paste comprising a silicone polymer and calcite powders, calibrated in order to match a SiO2/CaCO3 weight balance of 35/65. The scaffolds, fabricated with two slightly different geometries, were first cross-linked at 350 °C, then fired at 600 °C, in air. The low temperature adopted for the conversion of the polymer into amorphous silica, by thermo-oxidative decomposition, prevented the decomposition of calcite. The obtained silica-bonded calcite scaffolds featured open porosity of about 56%-64% and compressive strength of about 2.9-5.5 MPa, depending on the geometry. Dissolution studies in SBF and preliminary cell culture tests, with bone marrow stromal cells, confirmed the in vitro bioactivity of the scaffolds and their biocompatibility. The seeded cells were found to be alive, well anchored and spread on the samples surface. The new silica-calcite composites are expected to be suitable candidates as tissue-engineering 3D scaffolds for regeneration of cancellous bone defects.
Galarraga-Vinueza ME, Mesquita-Guimarães J, Magini RS, et al., 2017, Anti-biofilm properties of bioactive glasses embedding organic active compounds., J Biomed Mater Res A, Vol: 105, Pages: 672-679
Bioactive glasses (BGs) are promising materials for bone repair due to their desirable properties such as osteoconductivity, biodegradability, angiogenic potential, and antibacterial activity. Ionic dissolution products from bioactive glasses increase the medium pH inhibiting surrounding bacteria proliferation. The activity of BGs against biofilm formation has been enhanced by incorporating organic antibacterial compounds. The aim of this review was to summarize evidence in literature which assesses the efficacy of antibacterial and anti-biofilm compounds embedded in bioactive glasses to prevent peri-implant infection during bone healing. A PubMed bibliographical research was carried out including articles published in the last 20 years. Most previous studies evaluated antibacterial efficiency in planktonic cultures but did not investigate biofilm inhibition, underestimating biofilm clinical relevance. Multifactorial features such as biocompatibility of embedded compounds, receptor site characteristics, and drug delivery efficiency have been found to influence the bioactive glass capability of acting both as an anti-biofilm agent and as a bone repairing biomaterial. Accordingly, further in vitro and in vivo studies are required to select the most promising anti-biofilm agents which should be incorporated into bioactive glasses to counteract biofilm proliferation, without inducing toxic effects on human cells, and with the added functionality of promoting bone regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 672-679, 2017.
Heise S, Höhlinger M, Hernández YT, et al., 2017, Electrophoretic deposition and characterization of chitosan/bioactive glass composite coatings on Mg alloy substrates, Electrochimica Acta, Vol: 232, Pages: 456-464, ISSN: 0013-4686
© 2017 Elsevier LtdElectrophoretic deposition of chitosan-bioactive glass (45S5 composition) composite coatings on magnesium alloy (WE43) substrates was investigated. Two types of substrates were considered, one was the bare, non-pre-treated substrate, while the other one had been treated in Dulbecco's Modified Eagle Medium (DMEM). The protective effect of the coatings (of ∼2 μm in thickness) against corrosion was tested using electrochemical impedance spectroscopy and the coatings’ bioactive behaviour was determined in simulated body fluid. A tribo-mechanical characterization of the coatings was performed. Overall, results confirmed the importance of pre-treating the substrate to corrosion protective chitosan-bioactive glass coatings on WE43 alloy.
Hoppe A, Boccaccini AR, 2017, Chapter 16: Bioactive Glasses as Carriers of Therapeutic Ions and the Biological Implications, RSC Smart Materials, Pages: 362-392
© The Royal Society of Chemistry 2017.In the last few decades bioactive glasses (BGs) have been widely considered for bone tissue engineering applications due to their bioactivity and their osteogenic effects. The available scientific evidence suggests that ionic dissolution products (at a critical concentration) released during the degradation of the BG matrix induce osteogenic gene expression hence stimulating the bone regeneration process. Moreover, adding bioactive metallic ions (e.g. boron, copper, cobalt, lithium silver, zinc and strontium) to silicate as well as to phosphate and borate glasses has emerged as a promising route to develop novel BG formulations with specific therapeutic functionalities, including antibacterial, angiogenic, osteogenic and wound healing. The degradation behaviour of BGs can be tailored by adjusting the glass chemistry, making these biomaterials suitable carrier systems for controlled therapeutic ion release. This book chapter summarizes the fundamental aspects of the effect of ionic dissolution products released from BGs on osteogenesis and angiogenesis, also discussing novel BG compositions containing inorganic therapeutic agents. In vitro cellular as well as in vivo responses to specific therapeutic ions are discussed.
Höhlinger M, Heise S, Wagener V, et al., 2017, Developing surface pre-treatments for electrophoretic deposition of biofunctional chitosan-bioactive glass coatings on a WE43 magnesium alloy, Applied Surface Science, Vol: 405, Pages: 441-448, ISSN: 0169-4332
© 2017 Elsevier B.V.The use of Mg alloys as biodegradable implants requires optimizing the surface performance. A high number of surface modification and coating approaches have been previously explored, for instance to make magnesium and its alloys more corrosion resistant. The current study focuses on developing surface pre-treatments as a corrosion protection and primer for further surface modifications by electrophoretic deposition (EPD) of bioadaptive chitosan-bioactive glass coatings. For this, different surface treatments were tested on a WE43 Mg alloy. These treatments include immersion in Dulbecco's Modified Eagle's Medium (DMEM), a calcium phosphate treatment, immersion in hydrofluoric acid, and a hydrothermal procedure in NaOH. The resulting coatings were analyzed in view of the surface morphology and composition by SEM/EDX, as well as in view of their short-term corrosion protection ability by electrochemistry. Finally, the suitability of the different pre-treatments as an interfacial protection layer for subsequent EPD of a chitosan/bioactive glass-coating was explored.
© 2017 American Chemical Society.Metastable nanoparticles of vaterite were formed using a simple ultrasound technique. The effects of ultrasound amplitude and duration, as well as solution concentration, were investigated. The produced particles were characterized using standard X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning and transmission electron microscopies (SEM and TEM, respectively). As expected, the ultrasound synthesis process caused the particle size to be smaller than with conventional (magnetic bar) stirring, and allowed for the reaction time to be shortened as the crystallization rate was increased. As shown by XRD, FTIR, and SEM, the ultrasound process also led to the formation of pure vaterite, though the presence of calcite occurred as the ultrasound power was reduced and the pulse time increased. For both conventional and ultrasound techniques, the particle size was reduced with an increase in starting solution concentration. Using this technique allows for reproducible, tailored calcium carbonate particles for controlled drug delivery, as well as for use in composites for soft tissue repair; in particular, when used as the filler during electrospinning and melt electrospinning.
Karbowniczek J, Cordero-Arias L, Virtanen S, et al., 2017, Electrophoretic deposition of organic/inorganic composite coatings containing ZnO nanoparticles exhibiting antibacterial properties., Mater Sci Eng C Mater Biol Appl, Vol: 77, Pages: 780-789
To address one of the serious problems associated with permanent implants, namely bacterial infections, novel organic/inorganic coatings containing zinc oxide nanoparticles (nZnO) are proposed. Coatings were obtained by electrophoretic deposition (EPD) on stainless steel 316L. Different deposition conditions namely: deposition times in the range 60-300s and applied voltage in the range 5-30V as well as developing a layered coating approach were studied. Antibacterial tests against gram-positive Staphylococcus aureus and gram-negative Salmonella enteric bacteria confirmed the activity of nZnO to prevent bacterial growth. Coatings composition and morphology were analyzed by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Moreover, the corrosion resistance was analyzed by evaluation of the polarization curves in DMEM at 37°C, and it was found that coatings containing nZnO increased the corrosion resistance compared to the bare substrate. Considering all results, the newly developed coatings represent a suitable alternative for the surface modification of metallic implants.
Kaya S, Boccaccini AR, 2017, Electrophoretic deposition of zein coatings, Journal of Coatings Technology Research, Vol: 14, Pages: 683-689, ISSN: 1547-0091
© 2016, American Coatings Association.In this study, crack free, well-adhered and transparent zein coatings were obtained on 316L stainless steel substrates by electrophoretic deposition (EPD) employing varying deposition voltages and times. Obtained films were studied by Fourier transform infrared spectroscopy and scanning electron microscopy, and it was shown that the obtained coatings exhibit homogeneous and smooth surfaces. The deposition yield was investigated at various EPD conditions; the highest yield was found at 10 V and 10 min deposition time. The deposition mechanism was discussed by considering chemical reactions occurring during EPD. The EPD method developed here is attractive for the surface modification of metal implants by zein layers aiming at functionalizing surfaces for biomedical applications.
Macías-Andrés VI, Li W, Aguilar-Reyes EA, et al., 2017, Preparation and characterization of 45S5 bioactive glass-based scaffolds loaded with PHBV microspheres with daidzein release function., J Biomed Mater Res A, Vol: 105, Pages: 1765-1774
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microsphere loaded 45S5 bioactive glass (BG) based scaffolds with drug releasing capability have been developed. PHBV microspheres with a mean particle size 4 ± 2 μm loaded with daidzein were obtained by oil-in-water single emulsion solvent evaporation method and applied to the surface of BG scaffolds by dip coating technique. The morphology, in vitro bioactivity in simulated body fluid (SBF), mechanical properties and drug release kinetics of microsphere loaded scaffolds were studied. The microspheres were shown to be homogeneously dispersed on the scaffold surfaces. It was confirmed that hydroxyapatite crystals homogeneously grew not only on the surface of the scaffold but also on the surface of the microspheres within 3 days of immersion in SBF. The daidzein release from the microsphere loaded scaffolds lasted almost 1 month and was determined to be diffusion controlled. The microsphere loaded BG scaffolds with daidzein releasing capability obtained in this study are a candidate for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1765-1774, 2017.
Meincke T, Pacheco VM, Hoffmann D, et al., 2017, Engineering the surface functionality of 45S5 bioactive glass-based scaffolds by the heterogeneous nucleation and growth of silver particles, Journal of Materials Science, Pages: 1-9, ISSN: 0022-2461
© 2017 Springer Science+Business Media New YorkAn emerging topic in the field of biomaterials is the incorporation of silver ions, metallic silver or silver oxides into bioactive glasses to impart novel functionalities. In this work, a new approach of surface functionalization of 45S5 bioactive glass (BG) is introduced.In contrast to more common methods, which are based on the inclusion of silver during the sol–gel synthesis of BG, our method allows the surface functionalization of BG powders and BG scaffolds after their preparation. Hereby, we demonstrate the transferability of a previously reported approach on the wet chemical synthesis of cup-like and dendritic silver patches first from colloidal silica particles to BG particles and further to macroscopic highly porous BG scaffolds which were prepared by the sacrificial foam replica technique. The time-dependent silver releases of BG scaffolds with different silver loadings into simulated body fluid (SBF) were measured. Further studies were addressed to investigate the bioactivity of BG scaffolds before and after the silver coating procedure. It was found the silver deposition on 3D BG scaffolds did not affect the formation of crystalline hydroxyapatite during immersion into simulated body fluid.
Mesquita-Guimarães J, Leite MA, Souza JC, et al., 2017, Processing and strengthening of 58S bioactive glass-infiltrated titania scaffolds., J Biomed Mater Res A, Vol: 105, Pages: 590-600
In this work, TiO2 ceramic scaffolds were fabricated by the replica method using polyurethane (PU) sponges. Suspensions with high solid content were used to achieve scaffolds with improved mechanical behavior. TiO2 ceramic suspensions were optimized by rheological studies using different additives. It was found that the composition with 0.5 wt % Darvan enhanced the covering of the sponge struts. PU sponges of 45 to 80 ppi (pore per inch) were well coated without clogging pores. A thermal treatment with varying holding times, temperatures and heating rates was adjusted. The influence of different pore sizes on mechanical strength was evaluated. It was possible to obtain TiO2 scaffolds with 90% porosity and high pore interconnectivity, having compressive strength exceeding 0.6 MPa. TiO2 scaffolds were filled up with a 58S bioactive glass suspension to impart bioactive character to the scaffolds. These hybrid structures presented mechanical strengthening of about 26-213% depending on their sponge porosity. The prediction for cells viability via zeta potential measures indicated that this hybrid material is very promising for scaffold application with -19 to -25 mV between pH of 7.35-7.45. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 590-600, 2017.
Miguez-Pacheco V, Gorustovich AA, Boccaccini AR, et al., 2017, Chapter 15: Bioactive Glasses for Soft Tissue Engineering Applications, RSC Smart Materials, Pages: 336-361
© The Royal Society of Chemistry 2017.In the last few years the usage of bioactive glasses as scaffolds for soft tissue engineering has been investigated more thoroughly. The reason for the boost in interest is the attractive properties bioactive glasses offer, including bioactivity as well as antibacterial, angiogenic and hemostatic properties. So far, most research efforts have focused on applications for repairing skin and nerve tissue although there have been interesting developments in other fields including lung and intestine, which could potentially benefit a large group of patients. Three review articles on this topic have been published, so this chapter will mainly focus on the latest relevant findings. A great number of patents have been registered for the use of bioactive glass for hard tissue engineering. Recently, however, patents have been filed detailing the use of bioactive glass for soft tissue engineering applications which open the way to marketing bioactive glasses for soft tissue repair. The angiogenic effect of bioactive glasses and their dissolution products is of great interest for tissue engineering applications in general and in particular for soft tissue regeneration and repair. The third part of this chapter will detail the latest research on these angiogenic properties of bioactive glasses.
Moura D, Souza MT, Liverani L, et al., 2017, Development of a bioactive glass-polymer composite for wound healing applications., Mater Sci Eng C Mater Biol Appl, Vol: 76, Pages: 224-232
This study reports the production and characterization of a composite material for wound healing applications. A bioactive glass obtained by sol-gel process and doped with two different metal ions was investigated. Silver (Ag) and cobalt (Co) were chosen due to their antibacterial and angiogenic properties, respectively, very beneficial in the wound healing process. Poly(ε-caprolactone) (PCL) fibers were produced by electrospinning (ES) from a polymeric solution using acetone as a solvent. After optimization of the ES parameters, two main suspensions were prepared, namely: PCL containing bioactive glass nanoparticles (BG-NP) and PCL with Ag2O and CoO doped BG-NP (DP BG-NP), which were processed with different concentrations of BG-NP (0.25%, 0.5% and 0.75wt%). The composite membranes were characterized in terms of morphology, fiber diameter, weight loss, mineralization potential and mechanical performance.
Naseri S, Boccaccini AR, Nazhat SN, 2017, Chapter 10: Bioactive Glass Particulate-incorporated Polymer Composites, RSC Smart Materials, Pages: 236-256
© The Royal Society of Chemistry 2017.Bioactive glasses can potentially be used in combination with polymers in order to create a new complex of enhanced bioactivity, biocompatibility, and mechanical and degradation properties for biomedical applications. There are various processing routes to fabricate particulate bioactive glass fillers composites (dense or porous). Each fabrication route has its own advantages and disadvantages, and the best fabrication route is determined depending on the materials used and the desired final application. In this chapter, the main particulate bioactive glass-incorporated polymer composite fabrication techniques are presented, along with their associated pros and cons. Additionally, the properties of the various composites for tissue engineering and biomedical applications are discussed.
Nerantzaki M, Koliakou I, Kaloyianni MG, et al., 2017, A biomimetic approach for enhancing adhesion and osteogenic differentiation of adipose-derived stem cells on poly(butylene succinate) composites with bioactive ceramics and glasses, European Polymer Journal, Vol: 87, Pages: 159-173, ISSN: 0014-3057
© 2016 Elsevier LtdThe great potential application of poly(butylene succinate) (PBSu) as a novel biomaterial has not yet been realized, mainly owing to its insufficient bioactivity and low mechanical properties, which compromise the in vivo efficacy. Our strategy is based on the hypothesis that the incorporation of bioactive ceramics with similar microstructure to native bone structure into PBSu improves its bioactivity and affects new bone growth enhancing bone formation. Bioactive CaO–MgO–SiO2–Na2O–P2O5–CaF2 glass microparticles and fibrous hydroxyapatite nanoparticles were successfully synthesized and the resulting powders were characterized using different techniques. Afterwards, PBSu nanocomposites containing 2.5 wt% of micro-Bioglass (mBG), nano-hydroxyapatite (nHA) or mBG-nHA were prepared via in situ polymerization and were studied thoroughly in terms of their physicochemical and biological properties. We show here that our strategy was effective in accelerating the in vitro biodegradability of PBSu, in enhancing apatite formation in contact with simulated body fluid (SBF), while inducing cytocompatibility and osteogenic differentiation of rat Adipose Stem Cells (rASCs).
Nerantzaki MC, Koliakou IG, Kaloyianni MG, et al., 2017, New N-(2-carboxybenzyl)chitosan composite scaffolds containing nanoTiO<inf>2</inf> or bioactive glass with enhanced cell proliferation for bone-tissue engineering applications, International Journal of Polymeric Materials and Polymeric Biomaterials, Vol: 66, Pages: 71-81, ISSN: 0091-4037
© 2017, Copyright © Taylor & Francis Group, LLC.In the present study N-(2-carboxbenzyl)chitosan (CBCS) 3D macroporous hybrid scaffolds with interconnected pore system, containing 0.5, 2.5, and 5 wt% TiO2 nanoparticles (nTiO2) and 2.5 wt% Bioglass 45S5 (BG) have been synthesized using freeze-drying technique. Compressive strength values verified that the modification of chitosan combined with the presence of inorganic fillers can attribute significant mechanical stiffness to the scaffold. The in vitro biomineralization test confirmed that all samples were bioinert as mineral deposits were detected with X-ray diffractometry after incubation in SBF. Cytotoxicity and biocompatibility of all scaffolds were tested by using and Wharton’s jelly–derived mesenchymal stem cells (WJ-MSCs) and human embryonic kidney 293 (HEK 293) cell line. Metabolic activity, proliferation, migration, and attachment to the scaffolds were examined. Cells appeared to attach around the superficial pores and migrate in them. Cells also maintained their morphology, proliferated, and migrated across the scaffolds and showed consistent and proved compatibility.
Niklaus L, Tansaz S, Dakhil H, et al., 2017, Micropatterned Down-Converting Coating for White Bio-Hybrid Light-Emitting Diodes, Advanced Functional Materials, Vol: 27, ISSN: 1616-301X
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimWhite hybrid light-emitting diodes (WHLEDs) are considered as a solid approach toward environmentally sustainable lighting sources that meet the “Green Photonics” requirements. Here, WHLEDs with protein-based down-converting coatings, i.e., Bio-WHLEDs, are demonstrated and exhibit worthy white color quality, luminous efficiency, and stability values. The coatings feature a multilayered cascade-like architecture with thicknesses of 1–3 mm. This limits the efficiency due to the low optical transmittance. Thus, submillimeter coatings, where the location of the proteins is well-defined, are highly desired. It is in this context where the thrust of this work sets in. Here, a straightforward way to design microstructured single-layer coatings, in which the proteins are placed at our command by using 3D printing, is presented. Based on comprehensive spectroscopic and rheological investigations, the optimization of the matrix and the plotting to prepare different micropatterns, i.e., lines, open-grids, and closed-grids, is rationalized. The latter are applied to prepare Bio-WHLEDs with ≈5-fold enhancement of the luminous efficiency compared to the reference devices with a cascade-like coating, without losing stability and color quality. As such, this work shows a new route to exploit proteins for optoelectronics, setting a new avenue of research into the emerging field of Bio-WHLEDs.
Philippart A, Gómez-Cerezo N, Arcos D, et al., 2017, Novel ion-doped mesoporous glasses for bone tissue engineering: Study of their structural characteristics influenced by the presence of phosphorous oxide, Journal of Non-Crystalline Solids, Vol: 455, Pages: 90-97, ISSN: 0022-3093
© 2016 Elsevier B.V.Ion-doped binary SiO2-CaO and ternary SiO2-CaO-P2O5 mesoporous bioactive glasses were synthesized and characterized to evaluate the influence of P2O5 in the glass network structure. Strontium, copper and cobalt oxides in a proportion of 0.8 mol% were selected as dopants because the osteogenic and angiogenic properties reported for these elements. Although the four glass compositions investigated presented analogous textural properties, TEM analysis revealed that the structure of those containing P2O5 exhibited an increased ordered mesoporosity. Furthermore, 29Si NMR revealed that the incorporation of P2O5 increased the network connectivity and that this compound captured the Sr2 +, Cu2 + and Co2 + ions preventing them to behave as modifiers of the silica network. In addition, 31P NMR results revealed that the nature of the cation directly influences the characteristics of the phosphate clusters. In this study, we have proven that phosphorous oxide entraps doping-metallic ions, granting these glasses with a greater mesopores order.
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