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18 pages, 7927 KiB

Open AccessArticle

Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials

by Giorgia Montalbano, Sonia Fiorilli, Andrea Caneschi and Chiara Vitale-Brovarone

Materials 2018, 11(5), 700; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11050700 - 28 Apr 2018

Cited by 36 | Viewed by 5495

Abstract

Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct [...] Read more.

Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able to perform a sol-gel transition under physiological conditions. Field emission scanning electron microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate deposition. The high-water content promoted the strontium ion release from the embedded glass particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the suspension printability was assessed by means of rheological studies and preliminary extrusion tests, showing shear thinning and fast material recovery upon deposition. In conclusion, the reported results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone tissue engineering have been developed. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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16 pages, 5997 KiB

Open AccessArticle

Synthesis and Characterization of Silver-Doped Mesoporous Bioactive Glass and Its Applications in Conjunction with Electrospinning

by Francesca E. Ciraldo, Liliana Liverani, Lukas Gritsch, Wolfgang H. Goldmann and Aldo R. Boccaccini

Materials 2018, 11(5), 692; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11050692 - 28 Apr 2018

Cited by 46 | Viewed by 5346

Abstract

Since they were first developed in 2004, mesoporous bioactive glasses (MBGs) rapidly captured the interest of the scientific community thanks to their numerous beneficial properties. MBGs are synthesised by a combination of the sol–gel method with the chemistry of surfactants to obtain highly [...] Read more.

Since they were first developed in 2004, mesoporous bioactive glasses (MBGs) rapidly captured the interest of the scientific community thanks to their numerous beneficial properties. MBGs are synthesised by a combination of the sol–gel method with the chemistry of surfactants to obtain highly mesoporous (pore size from 5 to 20 nm) materials that, owing to their high surface area and ordered structure, are optimal candidates for controlled drug-delivery systems. In this work, we synthesised and characterised a silver-containing mesoporous bioactive glass (Ag-MBG). It was found that Ag-MBG is a suitable candidate for controlled drug delivery, showing a perfectly ordered mesoporous structure ideal for the loading of drugs together with optimal bioactivity, sustained release of silver from the matrix, and fast and strong bacterial inhibition against both Gram-positive and Gram-negative bacteria. Silver-doped mesoporous glass particles were used in three electrospinning-based techniques to produce PCL/Ag-MBG composite fibres, to coat bioactive glass scaffolds (via electrospraying), and for direct sol electrospinning. The results obtained in this study highlight the versatility and efficacy of Ag-substituted mesoporous bioactive glass and encourage further studies to characterize the biological response to Ag-MBG-based antibacterial controlled-delivery systems for tissue-engineering applications. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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14 pages, 13779 KiB

Open AccessFeature PaperArticle

Osteogenic Potential of Pre-Osteoblastic Cells on a Chitosan-graft-Polycaprolactone Copolymer

by Anthie Georgopoulou, Maria Kaliva, Maria Vamvakaki and Maria Chatzinikolaidou

Materials 2018, 11(4), 490; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11040490 - 26 Mar 2018

Cited by 25 | Viewed by 3939

Abstract

A chitosan-graft-polycaprolactone (CS-g-PCL) copolymer synthesized via a multi-step process was evaluated as a potential biomaterial for the adhesion and growth of MC3T3-E1 pre-osteoblastic cells. A strong adhesion of the MC3T3-E1 cells with a characteristic spindle-shaped morphology was observed from [...] Read more.

A chitosan-graft-polycaprolactone (CS-g-PCL) copolymer synthesized via a multi-step process was evaluated as a potential biomaterial for the adhesion and growth of MC3T3-E1 pre-osteoblastic cells. A strong adhesion of the MC3T3-E1 cells with a characteristic spindle-shaped morphology was observed from the first days of cell culture onto the copolymer surfaces. The viability and proliferation of the cells on the CS-g-PCL surfaces, after 3 and 7 days in culture, were significantly higher compared to the cells cultured on the tissue culture treated polystyrene (TCPS) control. The osteogenic potential of the pre-osteoblastic cells cultured on CS-g-PCL surfaces was evaluated by determining various osteogenic differentiation markers and was compared to the TCPS control surface. Specifically, alkaline phosphatase activity levels show significantly higher values at both time points compared to TCPS, while secreted collagen into the extracellular matrix was found to be higher on day 7. Calcium biomineralization deposited into the matrix is significantly higher for the CS-g-PCL copolymer after 14 days in culture, while the levels of intracellular osteopontin were significantly higher on the CS-g-PCL surfaces compared to TCPS. The enhanced osteogenic response of the MC3T3-E1 pre-osteoblasts cultured on CS-g-PCL reveals that the copolymer underpins the cell functions towards bone tissue formation and is thus an attractive candidate for use in bone tissue engineering. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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15 pages, 4366 KiB

Open AccessFeature PaperArticle

Surface Treatment of PEOT/PBT (55/45) with a Dielectric Barrier Discharge in Air, Helium, Argon and Nitrogen at Medium Pressure

by Pieter Cools, Mahtab Asadian, Wannes Nicolaus, Heidi Declercq, Rino Morent and Nathalie De Geyter

Materials 2018, 11(3), 391; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11030391 - 07 Mar 2018

Cited by 40 | Viewed by 4689

Abstract

This work describes the surface modification of 300PEO-PEOT/PBT 55/45 thin films using a medium pressure dielectric barrier discharge system operated in argon, helium, nitrogen or dry air to improve cell-surface interactions of this established biomaterial. The first part of the paper describes the [...] Read more.

This work describes the surface modification of 300PEO-PEOT/PBT 55/45 thin films using a medium pressure dielectric barrier discharge system operated in argon, helium, nitrogen or dry air to improve cell-surface interactions of this established biomaterial. The first part of the paper describes the optimization of the plasma processing parameters using water contact angle goniometry. The optimized samples are then characterized for changes in surface topography and surface chemical composition using atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XPS) respectively. For all plasma treatments, a pronounced increase in surface wettability was observed, of which the extent is dependent on the used plasma discharge gas. Except for dry air, only minor changes in surface topography were noted, while XPS confirmed that the changes in wettability were mainly chemical in nature with the incorporation of 5–10% of extra oxygen as a variety of polar groups. Similarly, for the nitrogen plasma, 3.8% of nitrogen polar groups were additionally incorporated. Human foreskin fibroblast (HFF) in vitro analysis showed that within the first 24 h after cell seeding, the effects on cell-surface interactivity were highly dependent on the used discharge gas, nitrogen plasma treatment being the most efficient. Differences between untreated and plasma-treated samples were less pronounced compared to other biodegradable materials, but a positive influence on cell adhesion and proliferation was still observed. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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17 pages, 3272 KiB

Open AccessArticle

Highly-Bioreactive Silica-Based Mesoporous Bioactive Glasses Enriched with Gallium(III)

by Sandra Sanchez-Salcedo, Gianluca Malavasi, Antonio J. Salinas, Gigliola Lusvardi, Luca Rigamonti, Ledi Menabue and Maria Vallet-Regi

Materials 2018, 11(3), 367; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11030367 - 02 Mar 2018

Cited by 28 | Viewed by 4572

Abstract

Beneficial effects in bone cell growth and antibacterial action are currently attributed to Ga³⁺ ions. Thus, they can be used to upgrade mesoporous bioactive glasses (MBGs), investigated for tissue engineering, whenever they released therapeutic amounts of gallium ions to the surrounding medium. [...] Read more.

Beneficial effects in bone cell growth and antibacterial action are currently attributed to Ga³⁺ ions. Thus, they can be used to upgrade mesoporous bioactive glasses (MBGs), investigated for tissue engineering, whenever they released therapeutic amounts of gallium ions to the surrounding medium. Three gallium-enriched MBGs with composition (in mol %) xSiO₂–yCaO–zP₂O₅–5Ga₂O₃, being x = 70, y = 15, z = 10 for Ga_1; x = 80, y = 12, z = 3 for Ga_2; and x = 80, y = 15, z = 0 for Ga_3, were investigated and compared with the gallium-free 80SiO₂–15CaO–5P₂O₅ MBG (B). ²⁹Si and ³¹P MAS NMR analyses indicated that Ga³⁺ acts as network modifier in the glass regions with higher polymerization degree and as network former in the zones with high concentration of classical modifiers (Ca²⁺ ions). Ga_1 and Ga_2 exhibited a quick in vitro bioactive response because they were coated by an apatite-like layer after 1 and 3 days in simulated body fluid. Although we have not conducted biological tests in this paper (cells or bacteria), Ga_1 released high but non-cytotoxic amounts of Ga³⁺ ions in Todd Hewitt Broth culture medium that were 140 times higher than the IC90 of Pseudomonas aeruginosa bacteria, demonstrating its potential for tissue engineering applications. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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11 pages, 6311 KiB

Open AccessArticle

Gentamicin-Releasing Mesoporous ZnO Structures

by Marco Laurenti and Valentina Cauda

Materials 2018, 11(2), 314; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11020314 - 22 Feb 2018

Cited by 25 | Viewed by 4696

Abstract

Among metal oxides, zinc oxide (ZnO) is one of the most attractive materials thanks to its biocompatible and biodegradable properties along with the existence of various morphologies featuring piezoelectric, semiconducting and photocatalytic activities. All of these structures were successfully prepared and tested for [...] Read more.

Among metal oxides, zinc oxide (ZnO) is one of the most attractive materials thanks to its biocompatible and biodegradable properties along with the existence of various morphologies featuring piezoelectric, semiconducting and photocatalytic activities. All of these structures were successfully prepared and tested for numerous applications, including optoelectronics, sensors and biomedical ones. In the last case, biocompatible ZnO nanomaterials positively influenced cells growth and tissue regeneration as well, promoting wound healing and new bone formation. Despite showing high surface areas, ZnO morphologies generally lack an intrinsic mesoporous structure, strongly limiting the investigation of the corresponding drug loading and release properties. Within this scope, this study focuses on the adsorption and release properties of high surface area, mesoporous ZnO structures using gentamicin sulfate (GS), a well known antibiotic against bacterial infections especially in orthopedics. The particular ZnO morphology was achieved starting from sputtered porous zinc layers, finally converted into ZnO by thermal oxidation. By taking advantage of this mesoporous framework, GS was successfully adsorbed within the ZnO matrix and the kinetic release profile evaluated for up to seven days. The adsorption of GS was successfully demonstrated, with a maximum amount of 263 mg effectively loaded per gram of active material. Then, fast kinetic release was obtained in vitro by simple diffusion mechanism, thus opening further possibilities of smart pore and surface engineering to improve the controlled delivery. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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22 pages, 7034 KiB

Open AccessFeature PaperArticle

On the Potential of Bulk Metallic Glasses for Dental Implantology: Case Study on Ti₄₀Zr₁₀Cu₃₆Pd₁₄

by Alethea Liens, Aurélien Etiemble, Pascaline Rivory, Sandra Balvay, Jean-Marc Pelletier, Sandrine Cardinal, Damien Fabrègue, Hidemi Kato, Philippe Steyer, Tais Munhoz, Jerome Adrien, Nicolas Courtois, Daniel J. Hartmann and Jérôme Chevalier

Materials 2018, 11(2), 249; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11020249 - 06 Feb 2018

Cited by 32 | Viewed by 5998

Abstract

Ti₄₀Zr₁₀Cu₃₆Pd₁₄ Bulk Metallic Glass (BMG) appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For [...] Read more.

Ti₄₀Zr₁₀Cu₃₆Pd₁₄ Bulk Metallic Glass (BMG) appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For the first time, a complete and exhaustive characterization of a unique batch of this glassy alloy was performed, together with ISO standard mechanical tests on machined implant-abutment assemblies. The results were compared to the benchmark Ti-6Al-4V ELI (Extra-Low-Interstitial) to assess its potential in dental implantology. The thermal stability, corrosion and sterilization resistance, cytocompatibility and mechanical properties were measured on samples with a simple geometry, but also on implant-abutment assemblies’ prototypes. Results show that the glassy alloy exhibits a quite high thermal stability, with a temperature range of 38 °C between the glass transition and crystallization, a compressive strength of 2 GPa, a certain plastic deformation (0.7%), a hardness of 5.5 GPa and a toughness of 56 MPa.√m. Moreover, the alloy shows a relatively lower Young’s modulus (96 GPa) than the Ti-6Al-4V alloy (110–115 GPa), which is beneficial to limit bone stress shielding. The BMG shows a satisfactory cytocompatibility, a high resistance to sterilization and a good corrosion resistance (corrosion potential of −0.07 V/SCE and corrosion current density of 6.0 nA/cm²), which may ensure its use as a biomaterial. Tests on dental implants reveal a load to failure 1.5-times higher than that of Ti-6Al-4V and a comparable fatigue limit. Moreover, implants could be machined and sandblasted by methods usually conducted for titanium implants, without significant degradation of their amorphous nature. All these properties place this metallic glass among a promising class of materials for mechanically-challenging applications such as dental implants. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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Review

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11 pages, 3082 KiB

Open AccessReview

Role of the Short Distance Order in Glass Reactivity

by María Vallet-Regi and Antonio J. Salinas

Materials 2018, 11(3), 415; https://0-doi-org.brum.beds.ac.uk/10.3390/ma11030415 - 11 Mar 2018

Cited by 12 | Viewed by 3717

Abstract

In 2005, our group described for the first time the structural characterization at the atomic scale of bioactive glasses and the influence of the glasses’ nanostructure in their reactivity in simulated body fluids. In that study, two bioactive sol-gel glasses with composition 80%SiO [...] Read more.

In 2005, our group described for the first time the structural characterization at the atomic scale of bioactive glasses and the influence of the glasses’ nanostructure in their reactivity in simulated body fluids. In that study, two bioactive sol-gel glasses with composition 80%SiO₂–20%CaO and 80%SiO₂–17%CaO–3%P₂O₅ (in mol-%) were characterized by High-Resolution Transmission Electron Microscopy (HRTEM). Such characterization revealed unknown features of the glasses’ structure at the local scale that allowed the understanding of their different in vitro behaviors as a consequence of the presence or absence of P₂O₅. Since then, the nanostructure of numerous bioactive glasses, including melt-prepared, sol-gel derived, and mesoporous glasses, was investigated by HRTEM, Nuclear Magnetic Resonance (NMR) spectroscopy, Molecular Dynamics (MD) simulations, and other experimental techniques. These studies have shown that although glasses are amorphous solids, a certain type of short distance order, which greatly influences the in vitro and in vivo reactivity, is always present. This paper reviews the most significant advances in the understanding of bioactive glasses that took place in the last years as a result of the growing knowledge of the glasses’ nanostructure. Full article

(This article belongs to the Special Issue Selected papers from EUROMAT 2017 Conference—Biomaterials)

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