Publications
285 results found
Ferreira SA, Tallia F, Heyraud A, et al., 2024, 3D printed hybrid scaffolds do not induce adverse inflammation in mice and direct human BM-MSC chondrogenesis in vitro, Biomaterials and Biosystems, Vol: 13, ISSN: 2666-5344
Biomaterials that can improve the healing of articular cartilage lesions are needed. To address this unmet need, we developed novel 3D printed silica/poly(tetrahydrofuran)/poly(ε-caprolactone) (SiO2/PTHF/PCL-diCOOH) hybrid scaffolds. Our aim was to carry out essential studies to advance this medical device towards functional validation in pre-clinical trials. First, we show that the chemical composition, microarchitecture and mechanical properties of these scaffolds were not affected by sterilisation with gamma irradiation. To evaluate the systemic and local immunogenic reactivity of the sterilised 3D printed hybrid scaffolds, they were implanted subcutaneously into Balb/c mice. The scaffolds did not trigger a systemic inflammatory response over one week of implantation. The interaction between the host immune system and the implanted scaffold elicited a local physiological reaction with infiltration of mononuclear cells without any signs of a chronic inflammatory response. Then, we investigated how these 3D printed hybrid scaffolds direct chondrogenesis in vitro. Human bone marrow-derived mesenchymal stem/stromal cells (hBM-MSCs) seeded within the 3D printed hybrid scaffolds were cultured under normoxic or hypoxic conditions, with or without chondrogenic supplements. Chondrogenic differentiation assessed by both gene expression and protein production analyses showed that 3D printed hybrid scaffolds support hBM-MSC chondrogenesis. Articular cartilage-specific extracellular matrix deposition within these scaffolds was enhanced under hypoxic conditions (1.7 or 3.7 fold increase in the median of aggrecan production in basal or chondrogenic differentiation media). Our findings show that 3D printed SiO2/PTHF/PCL-diCOOH hybrid scaffolds have the potential to support the regeneration of cartilage tissue.
De Mori A, Heyraud A, Tallia F, et al., 2024, Ovine Mesenchymal Stem Cell Chondrogenesis on a Novel 3D-Printed Hybrid Scaffold In Vitro., Bioengineering (Basel), Vol: 11, ISSN: 2306-5354
This study evaluated the use of silica/poly(tetrahydrofuran)/poly(ε-caprolactone) (SiO2/PTHF/PCL-diCOOH) 3D-printed scaffolds, with channel sizes of either 200 (SC-200) or 500 (SC-500) µm, as biomaterials to support the chondrogenesis of sheep bone marrow stem cells (oBMSC), under in vitro conditions. The objective was to validate the potential use of SiO2/PTHF/PCL-diCOOH for prospective in vivo ovine studies. The behaviour of oBMSC, with and without the use of exogenous growth factors, on SiO2/PTHF/PCL-diCOOH scaffolds was investigated by analysing cell attachment, viability, proliferation, morphology, expression of chondrogenic genes (RT-qPCR), deposition of aggrecan, collagen II, and collagen I (immunohistochemistry), and quantification of sulphated glycosaminoglycans (GAGs). The results showed that all the scaffolds supported cell attachment and proliferation with upregulation of chondrogenic markers and the deposition of a cartilage extracellular matrix (collagen II and aggrecan). Notably, SC-200 showed superior performance in terms of cartilage gene expression. These findings demonstrated that SiO2/PTHF/PCL-diCOOH with 200 µm pore size are optimal for promoting chondrogenic differentiation of oBMSC, even without the use of growth factors.
Turner J, Nandakumar A, Anilbhai N, et al., 2023, The effect of Si species released from bioactive glasses on cell behaviour: A quantitative review., Acta Biomater, Vol: 170, Pages: 39-52
Despite over 50 years of silicate bioactive glass (SBG) research, commercial success, and 6000+ published articles, there remains a lack of understanding of how soluble silicate (Si) species released from SBGs influences cellular responses. Using a systematic approach, this article quantitatively compares the in vitro responses of cells to SBG dissolution products reported in the literature and determines if there is a Si concentration ([Si]) dependent effect on cell behaviour. Cell behavioural responses to SBGs [Si] in dissolution products included metabolic activity (reported in 52 % of articles), cell number (24 %), protein production (22 %), gene expression (22 %) and biomineralization (24 %). There was a difference in the [Si] reported to cause increased (desirable) cellular responses (median = 30.2 ppm) compared to the [Si] reported to cause decreased (undesirable) cellular responses (median = 52.0 ppm) (P ≤ 0.001). The frequency of undesirable outcomes increased with increasing [Si], with ∼3 times more negative outcomes reported above 52 ppm. We also investigated the effect of [Si] on specific cellular outcomes (e.g., metabolic activity, angiogenesis, osteogenesis), if cell type/species influenced these responses and the impact of other ions (Ca, P, Na) within the SBG dissolution media on cell behaviour. This review has, for the first time, quantitatively compared the cellular responses to SBGs from the literature, providing a quantitative overview of SBG in vitro practices and presents evidence of a range of [Si] where desirable cellular responses may be more likely (30-52 ppm). This review also demonstrates the need for greater standardisation of in vitro methodological approaches and recommends some minimum reporting standards. STATEMENT OF SIGNIFICANCE: This systematic review investigates the relationship between the concentration of Si released from Si-bioactive glasses (SBG) and in vitro cell
Heyraud A, Tallia F, Sory D, et al., 2023, 3D printed hybrid scaffolds for bone regeneration using calcium methoxyethoxide as a calcium source, Frontiers in Bioengineering and Biotechnology, Vol: 11, Pages: 1-18, ISSN: 2296-4185
Introduction: Hybrids consist of inorganic and organic co-networks that are indistinguishable above the nanoscale, which can lead to unprecedented combinations of properties, such as high toughness and controlled degradation.Methods: We present 3D printed bioactive hybrid scaffolds for bone regeneration, produced by incorporating calcium into our “Bouncy Bioglass”, using calcium methoxyethoxide (CME) as the calcium precursor. SiO2-CaOCME/PTHF/PCL-diCOOH hybrid “inks” for additive manufacturing (Direct Ink Writing) were optimised for synergy of mechanical properties and open interconnected pore channels.Results and Discussion: Adding calcium improved printability. Changing calcium content (5, 10, 20, 30, and 40 mol.%) of the SiO2-CaOCME/PTHF/PCL-diCOOH hybrids affected printability and mechanical properties of the lattice-like scaffolds. Hybrids containing 30 mol.% calcium in the inorganic network (70S30CCME-CL) printed with 500 µm channels and 100 µm strut size achieved the highest strength (0.90 ± 0.23 MPa) and modulus of toughness (0.22 ± 0.04 MPa). These values were higher than Ca-free SiO2/PTHF/PCL-diCOOH hybrids (0.36 ± 0.14 MPa strength and 0.06 ± 0.01 MPa toughness modulus). Over a period of 90 days of immersion in simulated body fluid (SBF), the 70S30CCME-CL hybrids also kept a stable strain to failure (∼30 %) and formed hydroxycarbonate apatite within three days. The extracts released by the 70S30CCME-CL hybrids in growth medium did not cause cytotoxic effects on human bone marrow stromal cells over 24 h of culture.
Seewoonarain S, Ganesh D, Perera E, et al., 2023, Scaffold-associated procedures are superior to microfracture in managing focal cartilage defects in the knee: a systematic review & meta-analysis, Knee, Vol: 42, Pages: 320-338, ISSN: 0968-0160
BACKGROUND: Debate continues as to whether surgical treatment with chondral-regeneration devices is superior to microfracture for focal articular cartilage defects in the knee. PURPOSE: To evaluate the superiority of scaffold-associated chondral-regeneration procedures over microfracture by assessing: (1) Patient-reported outcomes; (2) Intervention failure; (3) Histological quality of cartilage repair. STUDY DESIGN: A three-concept keyword search strategy was designed, in accordance with PRISMA guidelines: (i) knee (ii) microfracture (iii) scaffold. Four databases (Ovid Medline, Embase, CINAHL and Scopus) were searched for comparative clinical trials (Level I-III evidence). Critical appraisal used two Cochrane tools: the Risk of Bias tool (RoB2) for randomized control trials and the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I). Study heterogeneity permitted qualitative analysis with the exception of three patient-reported scores, for which a meta-analysis was performed. RESULTS: Twenty-one studies were identified (1699 patients, age range 18-66 years): ten randomized control trials and eleven non-randomized study interventions. Meta-analyses of the International Knee Documentation Committee (IKDC), Knee Injury And Osteoarthritis Outcome Score (KOOS) for pain and activities of daily living, and Lysholm score demonstrated statistically significant improvement in outcomes for scaffold procedures compared to microfracture at two years. No statistical difference was seen at five years. CONCLUSION: Despite the limitations of study heterogeneity, scaffold-associated procedures appear to be superior to MF in terms of patient-reported outcomes at two years though similar at five years. Future evaluation would benefit from studies using validated clinical scoring systems, reporting failure, adverse events and long-term clinical follow up to determine technique safety and superiority.
Mohammed AA, Li S, Sang T, et al., 2023, Nanocomposite hydrogels with polymer grafted silica nanoparticles, using glucose oxidase, Gels, Vol: 9, Pages: 1-15, ISSN: 2310-2861
Nanocomposite hydrogels offer remarkable potential for applications in bone tissue engineering. They are synthesized through the chemical or physical crosslinking of polymers and nanomaterials, allowing for the enhancement of their behaviour by modifying the properties and compositions of the nanomaterials involved. However, their mechanical properties require further enhancement to meet the demands of bone tissue engineering. Here, we present an approach to improve the mechanical properties of nanocomposite hydrogels by incorporating polymer grafted silica nanoparticles into a double network inspired hydrogel (gSNP Gels). The gSNP Gels were synthesised via a graft polymerization process using a redox initiator. gSNP Gels were formed by grafting 2-acrylamido-2-methylpropanesulfonic acid (AMPS) as the first network gel followed by a sequential second network acrylamide (AAm) onto amine functionalized silica nanoparticles (ASNPs). We utilized glucose oxidase (GOx) to create an oxygen-free atmosphere during polymerization, resulting in higher polymer conversion compared to argon degassing. The gSNP Gels showed excellent compressive strengths of 13.9 ± 5.5 MPa, a strain of 69.6 ± 6.4%, and a water content of 63.4% ± 1.8. The synthesis technique demonstrates a promising approach to enhance the mechanical properties of hydrogels, which can have significant implications for bone tissue engineering and other soft tissue applications.
Ishihara D, Maçon ALB, Norris E, et al., 2023, Borosilicate sol–gel bioactive glasses and the effect of borate content on structure-property relationships, Journal of Sol-Gel Science and Technology, Pages: 1-11, ISSN: 0928-0707
Borate-doped silicate glasses with chemical compositions of (70 − x)SiO2–xB2O3–30CaO (x = 0, 5, 15, and 25, in mol%) were synthesized using the sol–gel method, intended to be used in tissue regeneration. The effects of borate content on the glass surface morphology, chemical structure, ion dissolution behavior, and fibroblast compatibility were investigated. 11B magic angle spinning-solid state nuclear magnetic resonance and Fourier transform infrared spectra demonstrated that borate, in the glasses, possessed both three- and four-coordinated structures. From nitrogen sorption, the specific surface area of the glasses decreased with increased borate content and calcination temperature, from 600 °C to 700 °C. In the case of glasses undergoing calcination at 700 °C, silicate and calcium ion released in a Tris–HCl buffer solution (pH = 7.4) at the early stage of the immersion test decreased as borate content increased. The decrease in surface area caused by stabilizing at 700 °C due to the effect of increasing borate concentration controlled the ion dissolution behavior of the glasses. The proliferation ability of fibroblasts cultured with the dissolution products of the glasses were improved as borate content increased in the glass composition.
Solanki A, Autefage H, Rodriguez A, et al., 2023, Cobalt containing glass fibres and their synergistic effect on the HIF-1 pathway for wound healing applications, Frontiers in Bioengineering and Biotechnology, Vol: 11, Pages: 1-15, ISSN: 2296-4185
Introduction and Methods: Chronic wounds are a major healthcare problem, but their healing may be improved by developing biomaterials which can stimulate angiogenesis, e.g. by activating the Hypoxia Inducible Factor (HIF) pathway. Here, novel glass fibres were produced by laser spinning. The hypothesis was that silicate glass fibres that deliver cobalt ions will activate the HIF pathway and promote the expression of angiogenic genes. The glass composition was designed to biodegrade and release ions, but not form a hydroxyapatite layer in body fluid.Results and Discussion: Dissolution studies demonstrated that hydroxyapatite did not form. When keratinocyte cells were exposed to conditioned media from the cobalt-containing glass fibres, significantly higher amounts of HIF-1α and Vascular Endothelial Growth Factor (VEGF) were measured compared to when the cells were exposed to media with equivalent amounts of cobalt chloride. This was attributed to a synergistic effect of the combination of cobalt and other therapeutic ions released from the glass. The effect was also much greater than the sum of HIF-1α and VEGF expression when the cells were cultured with cobalt ions and with dissolution products from the Co-free glass, and was proven to not be due to a rise in pH. The ability of the glass fibres to activate the HIF-1 pathway and promote VEGF expression shows the potential for their use in chronic wound dressings.
Young G, Tallia F, Clark J, et al., 2023, Hybrid materials with continuous mechanical property gradients that can be 3D printed, Materials Today Advances, Vol: 17, Pages: 1-9, ISSN: 2590-0498
Here, we show tough materials with continuous composition and stiffness gradients, without interfaces between regions, using inorganic/organic hybrid materials that can also be 3Dprinted. Sol-gel hybrid materials have interacting and interpenetrating organic and inorganic co-networks and can deliver a synergy of the properties of those constituents. Their mechanical behaviour can be tuned through inorganic/organic content and cross-linkingdensity. We describe hybrids of covalently linked silica-poly(tetrahydrofuran) (SiO 2 /PTHF) that show an unprecedented range of mechanical properties. SiO2 /PTHF hybrids were formed with different silica contents, producing materials ranging from elastomeric to glassy, with a compressive stiffness at 10% strain of between 2 and 200 MPa: at an SiO 2 content of 9 wt.%, hybrids show a failure stress in compression of 8 MPa, at 70% strain, and in tension of 2 MPa at 80% strain. Gradual sol-gel gelation was employed to generate monoliths with composition and stiffness gradients without visible joins or points of weakness, and for the development of ‘inks’ for additive manufacturing of 3D structures through direct ink writing. Monoliths with gradients were at least as strong, in tension and compression, as those made by casting a single sol. Cytocompatible materials with seamless stiffness gradients will have many applications: one is biomimicry of natural cartilaginous structures of the body, such as the intervertebral disc, which has a natural radial stiffness gradient.
Gritsch L, Bossard C, Jallot E, et al., 2022, Bioactive glass-based organic/inorganic hybrids: an analysis of the current trends in polymer design and selection., J Mater Chem B
Bioactive glass-based organic/inorganic hybrids are a family of materials holding great promise in the biomedical field. Developed from bioactive glasses following recent advances in sol-gel and polymer chemistry, they can overcome many limitations of traditional composites typically used in bone repair and orthopedics. Thanks to their unique molecular structure, hybrids are often characterized by synergistic properties that go beyond a mere combination of their two components; it is possible to synthesize materials with a wide variety of mechanical and biological properties. The polymeric component, in particular, can be tailored to prepare tough, load-bearing materials, or rubber-like elastomers. It can also be a key factor in the determination of a wide range of interesting biological properties. In addition, polymers can also be used within hybrids as carriers for therapeutic ions (although this is normally the role of silica). This review offers a brief look into the history of hybrids, from the discovery of bioactive glasses to the latest developments, with a particular emphasis on polymer design and chemistry. First the benefits and limitations of hybrids will be discussed and compared with those of alternative approaches (for instance, nanocomposites). Then, key advances in the field will be presented focusing on the polymeric component: its chemistry, its physicochemical and biological advantages, its drawbacks, and selected applications. Comprehensive tables summarizing all the polymers used to date to fabricate sol-gel hybrids for biomedical applications are also provided, to offer a handbook of all the available candidates for hybrid synthesis. In addition to the current trends, open challenges and possible avenues of future development are proposed.
Mohammed AA, Merrild NG, Li S, et al., 2022, Double-network hydrogels reinforced with covalently bonded silica nanoparticles via 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide chemistry, ACS Omega, Vol: 7, Pages: 43904-43914, ISSN: 2470-1343
Hydrogels have progressed from single-network materials with low mechanical integrity to double-network hydrogels (DNHGs) with tough, tunable properties. In this work, we introduce a nanocomposite structure into the first network of a DNHG. Amine-functionalized silica nanoparticles (ASNPs) were covalently cross-linked by forming amide bonds through the carboxylic groups of polyacrylic acid (PAAc) in the first network. DNHGs with varying sizes of ASNPs (50, 100, and 150 nm) and varying concentrations (2.5, 10, 20, and 40 wt %) were explored and compared to a control without a nanocomposite structure. Compressive strengths improved from 0.10 MPa for the control to a maximum of 1.28 MPa for the PAAc/PAAm DNHGs. All hydrogels experienced increased resistance to strain with a maximum of 74% compared to 45% for the control. SEM images of freeze-dried gels showed that ASNPs were integrated into the gel mesh. Nanoparticle retention was calculated using thermal gravimetric analysis (TGA) with improved retention values for larger ASNPs. New DNHG composites have been formed with improved mechanical properties and a potential use in tissue engineering and biomaterial applications.
Barrak FN, Li S, Mohammed AA, et al., 2022, Anti-inflammatory properties of S53P4 bioactive glass implant material., Journal of Dentistry, Vol: 127, ISSN: 0300-5712
OBJECTIVES: To assess whether the dissolution products of S53P4 bioactive glass (BG) affect cellular response of macrophages and clinically relevant peri-implant cell populations to dental implant particles in vitro. Cells chosen were human gingival fibroblasts (HGFs), osteoblasts and bone marrow derived stromal cells (HBMSCs). METHODS: Melt-derived S53P4 bioactive glass were prepared. HGFs, Saos-2 human osteoblastic cell line, HBMSCs and macrophages, derived from THP-1 human monocytic cell line, were cultured in the presence of particles from commercially pure titanium (Ti-CP4), grade 5 titanium alloy (Ti-6Al-4V), titanium-zirconium alloy (Ti-15Zr) or zirconia (Zr) (with respective diameters of 34.1 ± 3.8, 33.3 ± 4.4, 97.8 ± 8.2 and 71.3 ± 6.1 µm) with or without S53P4 dissolution products (conditioned media contained 327.30 ± 2.01 ppm Ca, 51.34 ± 0.41 ppm P and 61.48 ± 1.17 ppm Si, pH 8.01 ± 0.21). Inflammatory and macrophage polarisation markers including TNF-ɑ, IL-1, IL-6 and CD206 were quantified using enzyme-linked immunosorbent assay (ELISA). RESULTS: The presence of Ti-6Al-4V implant particles significantly induced the expression of pro-inflammatory markers in all tested cell types. S53P4 BG dissolution products regressed the particle induced up-regulation of pro-inflammatory markers and, appeared to suppress M1 macrophage polarisation. CONCLUSIONS: Implant particles, Ti-6Al-4V in particular, resulted in significant inflammatory responses from cells. S53P4 BG may possess anti-inflammatory properties and potentially mediate macrophage polarisation behaviour. CLINICAL SIGNIFICANCE: The findings highlight that the use and benefits of BG is a promising field of study. Authors believe more collective efforts are required to fully understand the reliability, efficiency and exact mechanisms of action of BG in the search for new generation of treatme
Ganeshaaraj G, Kaushalya S, Kondarage AI, et al., 2022, Semantic segmentation of micro-CT images to analyze bone ingrowth into biodegradable scaffolds., 44th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Publisher: IEEE, Pages: 3830-3833, ISSN: 1557-170X
The healing of bone fractures is a complex and well-orchestrated physiological process, but normal healing is compromised when the fracture is large. These large non-union fractures often require a template with surgical intervention for healing. The standard treatment, autografting, has drawbacks such as donor site pain and limited availability. Biodegradable scaffolds developed using biomaterials such as bioactive glass are a potential solution. Investigation of bone ingrowth into biodegradable scaffolds is an important aspect of their development. Micro-CT (μ-CT) imaging is widely used to evaluate and quantify tissue ingrowth into scaffolds in 3D. Existing segmentation techniques have low accuracy in differentiating bone and scaffold, and need improvements to accurately quantify the bone in-growth into the scaffold using μ-CT scans. This study proposes a novel 3-stage pipeline for better outcome. The first stage of the pipeline is based on a convolutional neural network for the segmentation of the scaffold, bone, and pores from μ-CT images to investigate bone ingrowth. A 3D rigid image registration procedure was employed in the next stage to extract the volume of interest (VOI) for the analysis. In the final stage, algorithms were developed to quantitatively analyze bone ingrowth and scaffold degradation. The best model for segmentation produced a dice similarity coefficient score of 90.1, intersection over union score of 83.9, and pixel accuracy of 93.1 for unseen test data.
Ren Y, Autefage H, Jones JR, et al., 2022, Developing atom probe tomography to characterize Sr-loaded bioactive glass for bone scaffolding, Microscopy and Microanalysis, Vol: 28, Pages: 1310-1320, ISSN: 1431-9276
In this study, atom probe tomography (APT) was used to investigate strontium-containing bioactive glass particles (BG-Sr10) and strontium-releasing bioactive glass-based scaffolds (pSrBG), both of which are attractive biomaterials with applications in critical bone damage repair. We outline the challenges and corresponding countermeasures of this nonconductive biomaterial for APT sample preparation and experiments, such as avoiding direct contact between focussed ion beam micromanipulators and the extracted cantilever to reduce damage during liftout. Using a low imaging voltage (≤3 kV) and current (≤500 pA) in the scanning electron microscope and a low acceleration voltage (≤2 kV) and current (≤200 pA) in the focussed ion beam prevents tip bending in the final stages of annular milling. To optimize the atom probe experiment, we considered five factors: total detected hits, multiple hits, the background level, the charge-state ratio, and the accuracy of the measured compositions, to explore the optimal laser pulse for BG-Sr10 bioactive glass. We show that a stage temperature of 30 K, 200–250 pJ laser pulse energy, 0.3% detection rate, and 200 kHz pulse rate are optimized experimental parameters for bioactive glass. The use of improved experimental preparation methods and optimized parameters resulted in a 90% successful yield of pSrBG samples by APT.
Skandalis A, Selianitis D, Sory DR, et al., 2022, Poly(2-(dimethylamino) ethyl methacrylate)-b-poly(lauryl methacrylate)-b-poly(oligo ethylene glycol methacrylate) triblock terpolymer micelles as drug delivery carriers for curcumin, JOURNAL OF APPLIED POLYMER SCIENCE, Vol: 139, ISSN: 0021-8995
Tallia F, Ting HK, Page S, et al., 2022, Bioactive, degradable and tough hybrids through calcium and phosphate incorporation, Frontiers in Materials, Vol: 9, ISSN: 2296-8016
We report the first inorganic/organic hybrids that show outstanding mechanical properties (withstanding cyclic loading) and bone bioactivity. This new hybrid material may fulfil the unmet clinical need for bioactive synthetic bone grafts that can withstand cyclic loading. A SiO2/PTHF/PCL-diCOOH sol-gel hybrid system, that combined inorganic and organic co-networks at the molecular level, previously demonstrated unprecedented synergy of properties, with excellent flexibility and promoted formation of articular cartilage matrix in vitro. Here, for the first time, calcium and phosphate ions were incorporated into the inorganic component of the hybrid network, to impart osteogenic properties. Calcium methoxyethoxide and triethyl phosphate were the calcium and phosphate precursors because they allow for incorporation into the silicate network at low temperature. The hybrid network was characterised with ATR-FTIR, XRD and solid-state NMR,which proved calcium and phosphate incorporation and suggested the Ca2+ ions also interacted with PCL-diCOOH through ionic bonds. This resulted in an increased strength (17-64 MPa) and modulus of toughness (2.5-14 MPa) compared to the original SiO2/PTHF/PCL-diCOOH hybrid material (which showed strength of ̃3 MPa and modulus of toughness of ̃0.35 MPa), while also maintaining the ability to withstand cyclic loading. The presence of calcium and phosphates in the silicate network resulted in a more congruent dissolution of the inorganic and organic co-networks in TRIS buffer. This was shown by the presence of silicon, calcium and phosphate ions along with PCL in the TRIS buffer after 1 week, whereas Ca-free hybrids mainly released PCL with negligible Si dissolution. The presence of calcium and phosphates also enabled deposition of hydroxycarbonate apatite following immersion in simulated body fluid, which was not seen on Ca-free hybrid. All hybrids passed cell cytotoxicity tests and supported pre-osteoblast cell attachment. The phosphate-fr
Barrak F, Li S, Muntane A, et al., 2022, Particle release from dental implants immediately after placement - An ex vivo comparison of different implant systems, Dental Materials, Vol: 38, Pages: 1004-1014, ISSN: 0109-5641
ObjectivesMetallic element release during implant placement can lead to mucositis and peri-implantitis. Here, using ex vivo porcine mandibles, the release of metallic elements into the surrounding bone with different material and geometrical designs was quantified.MethodsImplants from BioHorizons® and Straumann® (Bone level, tapered/cylindrical, 3/4 mm body diameter, Ti-CP4/Ti-6Al-4V/Ti-15Zr) systems were used. Micro computed tomography and inductively coupled plasma optical emission spectroscopy was used to visualise and quantify metallic elements in bone, following acid digestion. Implant surfaces were examined with scanning electron microscopy and internalization of implant particles by human gingival fibroblasts (HGFs) and RAW 264.7 macrophages were demonstrated in vitro.ResultsImplants with wider body diameters resulted in higher metallic element release. Ti-6Al-4V implants released significantly more metallic elements in comparison to both Ti-CP4 and Ti-15Zr devices with similar design and dimensions. Tapered Ti-CP4 implants released less compared to those with cylindrical design. Al three types of particles were internalized by HGFs and RAW 264.7.SignificanceTi-CP4 and Ti-15Zr appear to be more suitable materials, however, further studies are required to elucidate the biological effects of the fine particles and/or metallic species from dental implants. Authors would like to raise the awareness in the dental profession community that careful evaluation of the materials used in dental implants and the potential risks of the individual constituents of any alloy are needed. The potential cytotoxicity of Ti-6Al-4V implant particles should be highlighted. Further investigations on the biological effect of the fine particles or metallic species released from dental implants are also needed.
Thanasrisuebwong P, Jones JR, Eiamboonsert S, et al., 2022, Zinc-containing sol-gel glass nanoparticles to deliver therapeutic ions, Nanomaterials, Vol: 12, Pages: 1-25, ISSN: 2079-4991
Zn-containing dense monodispersed bioactive glass nanoparticles (Zn-BAGNPs) have been developed to deliver therapeutic inorganic trace elements, including Si, Ca, Sr, and Zn, to the cells through the degradation process, as delivery carriers for stimulating bone regeneration because of their capacity to induce osteogenic differentiation. The sol–gel-derived dense silica nanoparticles (SiO2-NPs) were first synthesized using the modified Stöber method, prior to incorporating therapeutic cations through the heat treatment process. The successfully synthesized monodispersed Zn-BAGNPs (diameter of 130 ± 20 nm) were homogeneous in size with spherical morphology. Ca, Sr and Zn were incorporated through the two-step post-functionalization process, with the nominal ZnO ratio between 0 and 2 (0, 0.5, 1.0, 1.5 and 2.0). Zn-BAGNPs have the capacity for continuous degradation and simultaneous ion release in SBF and PBS solutions due to their amorphous structure. Zn-BAGNPs have no in vitro cytotoxicity on the murine pre-osteoblast cell (MC3T3-E1) and periodontal ligament stem cells (PDLSCs), up to a concentration of 250 µg/mL. Zn-BAGNPs also stimulated osteogenic differentiation on PDLSCs treated with particles, after 2 and 3 weeks in culture. Zn-BAGNPs were not toxic to the cells and have the potential to stimulate osteogenic differentiation on PDLSCs. Therefore, Zn-BAGNPs are potential vehicles for therapeutic cation delivery for applications in bone and dental regenerations.
Jones JR, 2022, DESIGN OF PHYSIOLOGICAL BIOREACTORS THOUGH IMAGE ANALYSIS AND COMPUTATIONAL MODELLING, 6th World Congress of the Tissue-Engineering-and-Regenerative-Medicine-International-Society (TERMIS), Publisher: MARY ANN LIEBERT, INC, Pages: S3-S3, ISSN: 1937-3341
Kondarage A, Poologasundarampillai G, Nommeots-Nomm A, et al., 2022, In situ 4D tomography image analysis framework to follow sintering within 3D-printed glass scaffolds, Journal of the American Ceramic Society, Vol: 105, Pages: 1671-1684, ISSN: 0002-7820
We propose a novel image analysis framework to automate analysis of X-ray microtomography images of sintering ceramics and glasses, using open-source toolkits and machine learning. Additive manufacturing (AM) of glasses and ceramics usually requires sintering of green bodies. Sintering causes shrinkage, which presents a challenge for controlling the metrology of the final architecture. Therefore, being able to monitor sintering in 3D over time (termed 4D) is important when developing new porous ceramics or glasses. Synchrotron X-ray tomographic imaging allows in situ, real-time capture of the sintering process at both micro and macro scales using a furnace rig, facilitating 4D quantitative analysis of the process. The proposed image analysis framework is capable of tracking and quantifying the densification of glass or ceramic particles within multiple volumes of interest (VOIs) along with structural changes over time using 4D image data. The framework is demonstrated by 4D quantitative analysis of bioactive glass ICIE16 within a 3D-printed scaffold. Here, densification of glass particles within 3 VOIs were tracked and quantified along with diameter change of struts and interstrut pore size over the 3D image series, delivering new insights on the sintering mechanism of ICIE16 bioactive glass particles in both micro and macro scales.
Barrioni BR, de Carvalho SM, Naruphontjirakul P, et al., 2022, Cobalt-containing spherical glass nanoparticles for therapeutic ion release, Journal of the American Ceramic Society, Vol: 105, Pages: 1765-1777, ISSN: 0002-7820
Bioactive glass nanoparticles (BGNPs) can be internalized by cells, allowing the intracellular release of dissolution products with therapeutic benefit. Different therapeutic ions can be incorporated into the glass network that can promote angiogenesis via simulation of hypoxia conditions and consequent activation of pro-angiogenic genes. Here, novel monodispersed spherical dense BGNPs were obtained by a modified Stöber method with the SiO2–CaO–CoO composition, with diameters of 92 ± 1 nm, with cobalt as the pro-angiogenic ion. The presence of Co2+ species and the role of Co and Ca as network modifiers in the silica glass were confirmed by X-ray photoelectron spectroscopy and 29Si solid-state magic-angle spinning nuclear magnetic resonance, respectively. Controlled Co2+ ion release was observed in culture media, and no cytotoxicity was observed by (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cell viability assay on human osteosarcoma cells in direct contact with the nanoparticles. This study demonstrated that Co2+ ions can be incorporated into dense and spherical BGNPs, and these materials exhibit great potential as intracellular ion delivery systems with therapeutic properties.
Naruphontjirakul P, Li S, Pinna A, et al., 2022, Interaction of monodispersed strontium containing bioactive glass nanoparticles with macrophages, Biomaterials Advances, Vol: 133, Pages: 1-12, ISSN: 2772-9508
The cellular response of murine primary macrophages to monodisperse strontium containing bioactive glass nanoparticles (SrBGNPs), with diameters of 90 ± 10 nm and a composition (mol%) of 88.8 SiO2–1.8CaO-9.4SrO (9.4% Sr-BGNPs) was investigated for the first time. Macrophage response is critical as applications of bioactive nanoparticles will involve the nanoparticles circulating in the blood stream and macrophages will be the first cells to encounter the particles, as part of inflammatory response mechanisms. Macrophage viability and total DNA measurements were not decreased by particle concentrations of up to 250 μg/mL. The Sr-BGNPs were actively internalised by the macrophages via formation of endosome/lysosome-like vesicles bordered by a membrane inside the cells. The Sr-BGNPs degraded inside the cells, with the Ca and Sr maintained inside the silica network. When RAW264.7 cells were incubated with Sr-BGNPs, the cells were polarised towards the pro-regenerative M2 population rather than the pro-inflammatory M1 population. Sr-BGNPs are potential biocompatible vehicles for therapeutic cation delivery for applications in bone regeneration.
Lee Y, Lester D, Jones J, et al., 2021, Effect of polymer molecular mass and structure on the mechanical properties of polymer-glass hybrids, ACS Omega, Vol: 7, Pages: 786-792, ISSN: 2470-1343
Organic–inorganic hybrid materials are a promising class of materials for tissue engineering and other biomedical applications. In this systematic study, the effect of the polymer molecular mass (MM) with a linear architecture on hybrid mechanical properties is reported. Well-defined linear poly(methyl methacrylate-co-(3-(trimethoxysilyl)propyl methacrylate)) polymers with a range of MMs of 9 to 90 kDa and one 90 kDa star-shaped polymer were synthesized and then used to form glass–polymer hybrids. It was demonstrated that increasing linear polymer MM decreases the resultant hybrid mechanical strength. Furthermore, a star-polymer hybrid was synthesized as a comparison and demonstrated significantly different mechanical properties relative to its linear-polymer counterpart.
Narayan R, Basu B, Goel A, et al., 2021, Next generation bioceramics, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, ISSN: 0002-7820
Ju Q, Zenji T, Maçon ALB, et al., 2021, Silver-doped calcium silicate sol-gel glasses with a cotton-wool-like structure for wound healing, Materials Science and Engineering: C, Vol: 134, Pages: 112561-112561, ISSN: 0928-4931
Skin has excellent capacity to regenerate, however, in the event of a large injury or burn skin grafts are required to aid wound healing. The regenerative capacity further declines with increasing age and can be further exacerbated with bacterial infection leading to a chronic wound. Engineered skin substitutes can be used to provide a temporary template for the damaged tissue, to prevent/combat bacterial infection and promote healing. In this study, the sol-gel process and electrospinning were combined to fabricate 3D cotton-wool-like sol-gel bioactive glass fibers that mimic the fibrous architecture of skin extracellular matrix (ECM) and deliver metal ions for antibacterial (silver) and therapeutic (calcium and silica species) actions for successful healing of wounds. This study investigated the effects of synthesis and process parameters, in particular sintering temperature on the fiber morphology, the incorporation and distribution of silver and the degradation rate of fibers. Silver nitrate was found to decompose into silver nanoparticles within the glass fibers upon calcination. Furthermore, with increasing calcination temperature the nanoparticles increased in size from 3 nm at 600 °C to ~25 nm at 800 °C. The antibacterial ability of the Ag-doped glass fibers decreased as a function of the glass calcination temperature. The degradation products from the Ag-doped 3D non-woven sol-gel glass fibers were also found to promote fibroblast proliferation thus demonstrating their potential for use in skin regeneration.
Kondarage AI, Gayani B, Poologasundarampillai G, et al., 2021, Detection and tracking volumes of interest in 3D printed tissue engineering scaffolds using 4D imaging modalities., 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Pages: 1230-1233, ISSN: 1557-170X
Additive manufacturing (AM) platforms allow the production of patient tissue engineering scaffolds with desirable architectures. Although AM platforms offer exceptional control on architecture, post-processing methods such as sintering and freeze-drying often deform the printed scaffold structure. In-situ 4D imaging can be used to analyze changes that occur during post-processing. Visualization and analysis of changes in selected volumes of interests (VOIs) over time are essential to understand the underlining mechanisms of scaffold deformations. Yet, automated detection and tracking of VOIs in the 3D printed scaffold over time using 4D image data is currently an unsolved image processing task. This paper proposes a new image processing technique to segment, detect and track volumes of interest in 3D printed tissue engineering scaffolds. The method is validated using a 4D synchrotron sourced microCT image data captured during the sintering of bioactive glass scaffolds in-situ. The proposed method will contribute to the development of scaffolds with controllable designs and optimum properties for the development of patient-specific scaffolds.
Verdolotti L, Oliviero M, Lavorgna M, et al., 2021, “Aerogel-like” polysiloxane-polyurethane hybrid foams with enhanced mechanical and thermal-insulating properties, Composites Science and Technology, Vol: 213, Pages: 1-9, ISSN: 0266-3538
New organic-inorganic polyurethane-based hybrids with enhanced mechanical properties and thermal insulation properties are reported. Polyurethane-based hybrids are characterized by the intimate interactions of their inorganic and organic co-networks and prepared by sol-gel approach, have exhibited properties exceeding those of polyurethane foams, e.g. enhanced thermal stability, durability and thermal insulating effectiveness. However, mechanical properties have previously been poor. Here, new porous organic-inorganic materials consisting of a polyurethane network modified by in-situ formation of aerogel-like polysiloxane domains, were developed. They exhibit a multiscale-porosity which enhances the insulation, mechanical and thermal properties. The synthesis was performed through a novel stepwise process consisting of: preparation of a siloxane precursor based on methyl-triethoxysilane and tetraethoxysilane; functionalization of traditional polyol for polyurethane foams with 3-(triethoxysilanepropyl)isocyanate as coupling agent; use of suitable catalysts and silicone surfactants; and foaming with methylene-di-isocyanate compound. The siloxane precursors and coupling agent led to formation of “aerogel-like” polysiloxane domains within the walls and struts of the polyurethane foams. The synthesis method enabled increased incorporation of the “aerogel-like” polysiloxane structures into the foams, compared to literature, with 20 wt% SiO2, reducing thermal conductivity of the hybrid foams 30% compared with pristine polyurethane, in addition to significant improvement in thermal stability and mechanical properties.
Riveiro A, Amorim S, Solanki A, et al., 2021, Hyaluronic acid hydrogels reinforced with laser spun bioactive glass micro- and nanofibres doped with lithium, Materials Science and Engineering: C, Vol: 126, Pages: 1-12, ISSN: 0928-4931
The repair of articular cartilage lesions in weight-bearing joints remains as a significant challenge due to the low regenerative capacity of this tissue. Hydrogels are candidates to repair lesions as they have similar properties to cartilage extracellular matrix but they are unable to meet the mechanical and biological requirements for a successful outcome. Here, we reinforce hyaluronic acid (HA) hydrogels with 13-93-lithium bioactive glass micro- and nanofibres produced by laser spinning. The glass fibres are a reinforcement filler and a platform for the delivery of therapeutic lithium-ions. The elastic modulus of the composites is more than three times higher than in HA hydrogels. Modelling of the reinforcement corroborates the experimental results. ATDC5 chondrogenic cells seeded on the composites are viable and more proliferation occurs on the hydrogels containing fibres than in HA hydrogels alone. Furthermore, the chondrogenic behavior on HA constructs with fibres containing lithium is more marked than in hydrogels with no-lithium fibres.
Chung JJ, Yoo J, Sum BST, et al., 2021, 3D printed porous methacrylate/silica hybrid scaffold for bone substitution, Advanced Healthcare Materials, Vol: 10, Pages: 1-13, ISSN: 2192-2640
Inorganic–organic hybrid biomaterials made with star polymer poly(methyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) and silica, which show promising mechanical properties, are 3D printed as bone substitutes for the first time, by direct ink writing of the sol. Three different inorganic:organic ratios of poly(methyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate)-star-SiO2 hybrid inks are printed with pore channels in the range of 100–200 µm. Mechanical properties of the 3D printed scaffolds fall within the range of trabecular bone, and MC3T3 pre-osteoblast cells are able to adhere to the scaffolds in vitro, regardless of their compositions. Osteogenic and angiogenic properties of the hybrid scaffolds are shown using a rat calvarial defect model. Hybrid scaffolds with 40:60 inorganic:organic composition are able to instigate new vascularized bone formation within its pore channels and polarize macrophages toward M2 phenotype. 3D printing inorganic–organic hybrids with sophisticated polymer structure opens up possibilities to produce novel bone graft materials.
Pou-Alvarez P, Riveiro A, Ramon Novoa X, et al., 2021, Laser-guided corrosion control: a new approach to tailor the degradation of Mg-alloys, Small, Vol: 17, Pages: 1-10, ISSN: 1613-6810
Despite corrosion being commonly seen as a problem to be avoided, applications such as batteries or biodegradable implants do benefit from corrosion‐like phenomena. However, current strategies address corrosion control from a global perspective for a whole component, without considering local adaptations to functionality specifications or inhomogeneous environments. Here, a novel concept is presented: the local control and guidance of corrosion through a laser surface treatment. Immersion tests in saline solution of AZ31 magnesium alloy samples show degradation rates reduced up to 15 times with the treatment, owing to a fast passivation after the induced microstructural modifications. By controlling the treatment conditions, the degradation can be restricted to delimited regions and driven towards specific directions. The applicability of the method for the design of tailored degradation biomedical implants is demonstrated and uses for cathodic protection systems and batteries can also be anticipated.
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