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  • 1.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Chen, Song
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON, Canada..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fabrication of translucent nanoceramics via a simple filtration method2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 121, p. 99848-99855Article in journal (Refereed)
    Abstract [en]

    Generally, particle packing density, grain size and morphology are the important factors that affect the transparency of ceramics. In order to achieve better transparency of ceramics, efforts should be developed to eliminate or minimize light scattering or absorption. Therefore the porosity and size of crystals in a ceramic body should be strictly controlled. Typical transparent ceramics are fabricated by pressure-assisted sintering techniques such as hot isostatic pressing (HIP), spark plasma sintering (SPS), and pressure-less sintering (PLS). However, a simple energy efficient production method remains a challenge. In this study, we describe a simple fabrication process via a facile filtration system that can fabricate translucent hydroxyapatite based ceramics. The translucent pieces yielded from filtration exhibit optical transmittance that was confirmed by UV spectroscopy. Briefly, the morphology and size of ceramic nanoparticles, filtration pressure and filtration time are important parameters to be discussed. Compared with different hydroxyapatite nanoparticles, spherical nanoparticles easily form a densely packed structure, followed by sintered ceramics. When the strontium content in HA increases, the morphology of HA changes from nano-spheres to nano-rods, following a decrease in transparency. A pressure filtration model combining Darcy's law and the Kozeny-Carman relation has been discussed to simulate and explain why the translucent ceramics can be fabricated via such a simple process. This method could be further applied to prepare other translucent functional ceramics by controlling the size and morphology of ceramic particles.

  • 2.
    Chen, Song
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    McMaster University.
    Yu, Shun
    KTH.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Synthesis of calcium phosphate crystals with thin nacreous structure2016In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 18, no 6, p. 1064-1069Article in journal (Refereed)
    Abstract [en]

    Nacre-like structures have attracted great interest in recent years due to their outstanding toughness, stiffness and impact resistance. However, there is a challenge associated with engineering nacre-like calcium phosphate crystals. In this study, thin nacreous-like monetite sheets were synthesized in solutions guided by a surfactant. The influence of temperature, initial pH, Ca/P ratio, stirring time and the concentration of cetyltrimethylammonium bromide (CTAB) on the nacre-like structure has been studied. Findings showed that a nacre-like structure could only be formed at a high temperature (90 degrees C), high initial pH (11), sufficient stirring time (3 h), and under the presence of CTAB. A small-angle X-ray scattering experiment carried out at a synchrotron radiation facility showed that the distance between nanolayers was around 2.6 nm and TEM confirmed the fine sheet-like structure. The mechanism of the formation the nacre-like structure and its characterization were discussed.

  • 3.
    Forsgren, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Frykstrand, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    A Template-Free, Ultra-Adsorbing, High Surface Area Carbonate Nanostructure2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 7, p. e68486-Article in journal (Refereed)
    Abstract [en]

    We report the template-free, low-temperature synthesis of a stable, amorphous, and anhydrous magnesium carbonate nanostructure with pore sizes below 6 nm and a specific surface area of ~ 800 m2 g−1, substantially surpassing the surface area of all previously described alkali earth metal carbonates. The moisture sorption of the novel nanostructure is featured by a unique set of properties including an adsorption capacity ~50% larger than that of the hygroscopic zeolite-Y at low relative humidities and with the ability to retain more than 75% of the adsorbed water when the humidity is decreased from 95% to 5% at room temperature. These properties can be regenerated by heat treatment at temperatures below 100°C.The structure is foreseen to become useful in applications such as humidity control, as industrial adsorbents and filters, in drug delivery and catalysis.

  • 4.
    Fu, Le
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wu, Chengtie
    Grandfield, Kathryn
    McMaster University.
    Chang, Jiang
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Spark plasma sintering consolidated transparent ZrO2- SiO2 glass ceramic containing nano-sized ZrO2 spheres2016Conference paper (Refereed)
  • 5.
    Fu, Le
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wu, Chengtie
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China..
    Grandfield, Kathryn
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON, Canada.;McMaster Univ, Sch Biomed Engn, Hamilton, ON, Canada..
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Chang, Jiang
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Transparent single crystalline ZrO2-SiO2 glass nanoceramic sintered by SPS2016In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 36, no 14, p. 3487-3494Article in journal (Refereed)
    Abstract [en]

    Transparent ZrO2-SiO2 glass ceramics show potential for application in the dental industry. The application of this material prepared by a sol-gel method was hindered by the difficulties in obtaining large dimension samples. Spark plasma sintering (SPS) offers the possibility of achieving transparent ZrO2-SiO2 glass ceramics. In this study, a ZrO2-SiO2 powder was prepared by the sol-gel method and subsequently sintered by SPS. Varied sintering temperatures and pressures were explored to achieve better mechanical strength and transparency. TEM results showed single crystalline ZrO2 spherical nanocrystals (approximately 20 nm) homogenously embedded in the SiO2 matrix. Tetragonal ZrO2 was the only crystalline phase in all specimens. With sintering conditions of 1200 degrees C and 30 MPa, a glass ceramic with fracture toughness of 4.13 MPa was obtained. This value is similar to the commercial dental glass ceramic of IPS e.max (R) Press. The studied transparent glass ceramic with high transparency and moderate mechanical strength shows promise for dental application.

  • 6.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Electron tomography: A tool for the study of osseointegration in 3D2010Conference paper (Refereed)
  • 7.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Nanoscale Osseointegration: Characterization of Biomaterials and their Interfaces with Electron Tomography2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Bone response is one of the key determining factors in the overall success of biomaterials intended for bone regeneration and osseointegration. Understanding the formation of bone at an implant surface may lead to the improved design of biomaterials for the future. However, due to the inhomogeneity of bone tissue at an interface, two-dimensional images often lack detail on the interfacial complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar nano length scale.

    While current analysis methods, such as X-ray tomography, transmission electron microscopy, focused ion beam microscopy and scanning electron microscopy, provide a basis for analysing biomaterials and biointerfaces, they are incapable of doing so with both nanometre resolution and three-dimensional clarity. In contrast, electron tomography may be used to characterize the three-dimensional structure of biomaterials and their interfaces to bone with nanometre resolution.

    In this work, hydroxyapatite scaffolds, and laser-modified titanium and Ti6Al4V implants were studied in contact with human or rabbit bone. Z-contrast electron tomography revealed that the orientation of collagen in bone apposing hydroxyapatite, titanium and Ti6Al4V implants is consistently parallel to the implant surface, where the bioactive layer that precipitates on HA is oriented perpendicular to the implant surface. With this method, complete three-dimensional nanoscale osseointegration of titanium-based implants was also established.

    The extension of this technique from interfacial analyses to the design of biomaterials provided an understanding of the pore structure of mesoporous titania. In further investigations, the open three-dimensional pore network, as revealed by electron tomography, showed promise as a coating that improves implant osseointegration and enables site-specific drug-delivery from an implant surface.

    In summary, it was demonstrated that two-dimensional characterization techniques were insufficient for the investigation of nanostructured biomaterials, as well as their interfaces to bone. Visualizing biointerfaces and biomaterials with nanometre precision in three-dimensions can expose new fundamental information on materials properties and bone response, enabling better design of biomaterials for the future.

    List of papers
    1. Bone response to free form fabricated hydroxyapatite and zirconia scaffolds: a transmission electron microscopy study in the human maxilla
    Open this publication in new window or tab >>Bone response to free form fabricated hydroxyapatite and zirconia scaffolds: a transmission electron microscopy study in the human maxilla
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    2012 (English)In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 14, no 3, p. 461-469Article in journal (Refereed) Published
    Abstract [en]

    Background: Understanding the interfacial reactions to synthetic bone regenerative scaffolds in vivo is fundamental for improving osseointegration and osteogenesis. Using transmission electron microscopy, it is possible to study the biological response of hydroxyapatite (HA) and zirconia (ZrO2) scaffolds at the nanometer scale.

    Purpose: In this study, the bone-bonding abilities of HA and ZrO2 scaffolds produced by free-form fabrication were evaluated in the human maxilla at 3 months and 7 months.

    Materials and Methods: HA and ZrO2 scaffolds (ø: 3 mm) were implanted in the human maxilla, removed with surrounding bone, embedded in resin, and sectioned. A novel focused ion beam (FIB) sample preparation technique enabled the production of thin lamellae for study by scanning transmission electron microscopy.

    Results: Interface regions were investigated using high-angle annular dark-field imaging and energy-dispersive X-ray spectroscopy analysis. Interfacial apatite layers of 80 nm and 50 nm thickness were noted in the 3- and 7-month HA samples, respectively, and bone growth was discovered in micropores up to 10 µm into the samples.

    Conclusions: The absence of an interfacial layer in the ZrO2 samples suggest the formation of a direct contact with bone, while HA, which bonds through an apatite layer, shows indications of resorption with increasing implantation time. This study demonstrates the potential of HA and ZrO2 scaffolds for use as bone regenerative materials.

    Keywords
    FIB, free-form fabrication, hydroxyapatite, scaffolds, TEM, zirconia
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-122088 (URN)10.1111/j.1708-8208.2009.00270.x (DOI)000304759300019 ()
    Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2018-02-08Bibliographically approved
    2. Visualizing biointerfaces in three dimensions: electron tomography of the bone-hydroxyapatite interface
    Open this publication in new window or tab >>Visualizing biointerfaces in three dimensions: electron tomography of the bone-hydroxyapatite interface
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    2010 (English)In: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 7, no 51, p. 1497-501Article in journal (Refereed) Published
    Abstract [en]

    A positive interaction between human bone tissue and synthetics is crucial for the success of bone-regenerative materials. A greater understanding of the mechanisms governing bone-bonding is often gained via visualization of the bone-implant interface. Interfaces to bone have long been imaged with light, X-rays and electrons. Most of these techniques, however, only provide low-resolution or two-dimensional information. With the advances in modern day transmission electron microscopy, including new hardware and increased software computational speeds, the high-resolution visualization and analysis of three-dimensional structures is possible via electron tomography. We report, for the first time, a three-dimensional reconstruction of the interface between human bone and a hydroxyapatite implant using Z-contrast electron tomography. Viewing this structure in three dimensions enabled us to observe the nanometre differences in the orientation of hydroxyapatite crystals precipitated on the implant surface in vivo versus those in the collagen matrix of bone. Insight into the morphology of biointerfaces is considerably enhanced with three-dimensional techniques. In this regard, electron tomography may revolutionize the approach to high-resolution biointerface characterization.

    Keywords
    hydroxyapatite, bone, transmission, electron microscopy, electron tomography
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-133206 (URN)10.1098/rsif.2010.0213 (DOI)000281281000010 ()20534599 (PubMedID)
    Available from: 2010-11-03 Created: 2010-11-03 Last updated: 2018-02-08Bibliographically approved
    3. High-resolution three-dimensional probes of biomaterials and their interfaces
    Open this publication in new window or tab >>High-resolution three-dimensional probes of biomaterials and their interfaces
    2012 (English)In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 370, no 1963, p. 1337-1351Article in journal (Refereed) Published
    Abstract [en]

    Interfacial relationships between biomaterials and tissues strongly influence the success of implant materials and their long-term functionality. Owing to the inhomogeneity of biological tissues at an interface, in particular bone tissue, two-dimensional images often lack detail on the interfacial morphological complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar length scale. Electron tomography (ET) can meet these challenges by enabling high-resolution three-dimensional imaging of biomaterial interfaces. In this article, we review the fundamentals of ET and highlight its recent applications in probing the three-dimensional structure of bioceramics and their interfaces, with particular focus on the hydroxyapatite-bone interface, titanium dioxide-bone interface and a mesoporous titania coating for controlled drug release.

    Keywords
    electron tomography, interface, hydroxyapatite, bone, titanium dioxide, implant interface
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-171539 (URN)10.1098/rsta.2011.0253 (DOI)000300631900004 ()
    Available from: 2012-03-21 Created: 2012-03-21 Last updated: 2018-02-08Bibliographically approved
    4. Resolving the CaP-bone interface: A review of discoveries with light and electron microscopy
    Open this publication in new window or tab >>Resolving the CaP-bone interface: A review of discoveries with light and electron microscopy
    2012 (English)In: Biomatter, ISSN 2159-2527, Vol. 2, no 1, p. 15-23Article in journal (Refereed) Published
    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-179313 (URN)10.4161/biom.20062 (DOI)
    Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2018-02-08Bibliographically approved
    5. Bone-titanium oxide interface in humans revealed by transmission electron microscopy and electron tomography
    Open this publication in new window or tab >>Bone-titanium oxide interface in humans revealed by transmission electron microscopy and electron tomography
    Show others...
    2012 (English)In: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 9, no 67, p. 396-400Article in journal (Refereed) Published
    Abstract [en]

    Osseointegration, the direct contact between an implant surface and bone tissue, plays a critical role in interfacial stability and implant success. Analysis of interfacial zones at the micro- and nano-levels is essential to determine the extent of osseointegration. In this paper, a series of state-of-the-art microscopy techniques are used on laser-modified implants retrieved from humans. Partially laser-modified implants were retrieved after two and a half months' healing and processed for light and electron microscopy. Light microscopy showed osseointegration, with bone tissue growing both towards and away from the implant surface. Transmission electron microscopy revealed an intimate contact between mineralized bone and the laser-modified surface, including bone growth into the nano-structured oxide. This novel observation was verified by three-dimensional Z-contrast electron tomography, enabling visualization of an apatite layer, with different crystal direction compared with the apatite in the bone tissue, encompassing the nano-structured oxide. In conclusion, the present study demonstrates the nano-scale osseointegration and bonding between apatite and surface-textured titanium oxide. These observations provide novel data in human specimens on the ultrastructure of the titanium–bone interface.

    Keywords
    dental implant, laser, focused ion beam, transmission electron microscopy, electron tomography, bone
    National Category
    Medical Materials Engineering and Technology
    Research subject
    Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-160563 (URN)10.1098/rsif.2011.0420 (DOI)000298380100018 ()
    Available from: 2011-10-25 Created: 2011-10-25 Last updated: 2017-12-08Bibliographically approved
    6. Three-dimensional structure of laser-modified Ti6Al4V and bone interface revealed with STEM tomography
    Open this publication in new window or tab >>Three-dimensional structure of laser-modified Ti6Al4V and bone interface revealed with STEM tomography
    2013 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 127, p. 48-52Article in journal (Refereed) Published
    Abstract [en]

    The early interaction between an implant's surface and bone is a leading factor for implant success, where multiple surface properties contribute to improved bone anchorage. An important parameter is surface topography, both on the micron and nanoscale. Laser-modification has been performed in the thread valleys of Ti6Al4V screws to alter their surface chemistry and topography to form a nanostructured surface titanium-dioxide. Implants were placed in the rabbit tibia, removed with surrounding bone after 8 weeks, fixated, dried and resin embedded. Focused ion beam milling (FIB) was used to prepare specimens from the resin blocks for transmission electron microscopy (TEM). Z-contrast electron tomography offered the possibility to explore the interfacial structure with high-resolution in three-dimensions. With this technique, collagen fibers of the surrounding bone appear to have been laid down parallel to the implant surface. Accordingly, visualization of the laser-modified interface with nanoscale three-dimensional resolution, as offered by Z-contrast electron tomography, gives new insights into bone bonding mechanisms between roughened titanium-dioxide surfaces and bone.

    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-179312 (URN)10.1016/j.ultramic.2012.07.007 (DOI)000316659100008 ()
    Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2018-02-08Bibliographically approved
    7. Mesoporous titanium dioxide coating for metallic implants
    Open this publication in new window or tab >>Mesoporous titanium dioxide coating for metallic implants
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    2012 (English)In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 100B, no 1, p. 82-93Article in journal (Refereed) Published
    Abstract [en]

    A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self-assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m2/g and average pore diameter of 4.3 nm. Adhesion tests using the scratch method and an in situ screw-in/screw-out technique confirm that the MT coating bonds tightly with the metallic substrate, even after removal from bone. Because of its high surface area, the bioactivity of the MT coating is much better than that of a dense TiO2 coating of the same composition. Quick formation of hydroxyapatite (HA) in vitro can be related to enhance bonding with bone. The uptake of antibiotics by the MT coating reached 13.4 mg/cm3 within a 24 h loading process. A sustained release behavior has been obtained with a weak initial burst. By using Cephalothin as a model drug, drug loaded MT coating exhibits a sufficient antibacterial effect on the material surface, and within millimeters from material surface, against E.coli. Additionally, the coated and drug loaded surfaces showed no cytotoxic effect on cell cultures of the osteoblastic cell line MG-63. In conclusion, this study describes a novel, biocompatiblemesoporous implant coating, which has the ability to induce HA formation and could be used as a surface drug-delivery system.

    Keywords
    mesoporous materials, titanium oxide, drug delivery, bioactivity, implant coating
    National Category
    Biomaterials Science Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Materials Science
    Identifiers
    urn:nbn:se:uu:diva-159881 (URN)10.1002/jbm.b.31925 (DOI)000297949800010 ()
    Available from: 2011-10-11 Created: 2011-10-11 Last updated: 2018-02-08Bibliographically approved
  • 8.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Characterization of dental interfaces with electron tomography2014In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 9, no 2, p. 029001-Article in journal (Refereed)
    Abstract [en]

    Understanding the interface between dental materials and tooth is critical in the prevention of secondary caries. Assessing this interface with high-resolution clarity has traditionally been challenging. This work highlights electron tomography, carried out in the transmission electron microscope, as a novel technique to obtain both three-dimensional and nanometer scaled information on dental materials in contact with dentin. In this study, commercial calcium aluminate and glass ionomer based luting agents in contact with human dentin were prepared for electron microscopy via focused ion beam milling. Imaging with high-angle annular dark field provided compositional contrast, and combined with tilting over large angular ranges, enabled the reconstruction of the three-dimensional interface between tissue and cement. The characteristics of the interface were observed with this extra dimensionality and superior resolution, providing evidence for the viability of this technique in interfacial studies of dental materials. 

  • 9.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Focused ion beam in the study of biomaterials and biological matter2012In: Advances in Materials Science and Engineering, ISSN 1687-8434, p. 841961-Article in journal (Refereed)
    Abstract [en]

    The application of focused ion beam (FIB) techniques in the life sciences has progressed by leaps and bounds over the past decade. A once dedicated ion beam instrument, the focused ion beam today is generally coupled with a plethora of complementary tools such as dual-beam scanning electron microscopy (SEM), environmental SEM, energy dispersive X-ray spectroscopy (EDX), or cryogenic possibilities. All of these additions have contributed to the advancement of focused ion beam use in the study of biomaterials and biological matter. Biomaterials, cells, and their interfaces can be routinely imaged, analyzed, or prepared for techniques such as transmission electron microscopy (TEM) with this comprehensive tool. Herein, we review the uses, advances, and challenges associated with the application of FIB techniques to the life sciences, with particular emphasis on TEM preparation of biomaterials, biological matter, and their interfaces using FIB.

  • 10.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ericson, Fredric
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Sanden, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Johansson, Carina
    School of health and medical sciences, Örebro University.
    Larsson, Sune
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Botton, Gianluigi
    Dept of Materials Science and Engineering, McMaster University, Hamilton, Ontario, Kanada.
    Palmquist, Anders
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg.
    Thomsen, Peter
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg.
    Håkan, Engqvist
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ultrastructural characterization of the hydroxyapatite-coated pedicle screw and human bone interface2012In: International Journal of Nano and Biomaterials, ISSN 1752-8941, Vol. 4, no 1, p. 1-11Article in journal (Refereed)
  • 11.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Gustafsson, Stefan
    Palmquist, Anders
    Where bone meets implant: the characterization of nano-osseointegration2013In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 5, no 10, p. 4302-4308Article in journal (Refereed)
    Abstract [en]

    The recent application of electron tomography to the study of biomaterial interfaces with bone has brought about an awareness of nano-osseointegration and, to a further extent, demanded increasingly advanced characterization methodologies. In this study, nanoscale osseointegration has been studied via laser-modified titanium implants. The micro- and nano-structured implants were placed in the proximal tibia of New Zealand white rabbits for six months. High-resolution transmission electron microscopy (HRTEM), analytical microscopy, including energy dispersive X-ray spectroscopy (EDXS) and energy-filtered TEM (EFTEM), as well as electron tomography studies were used to investigate the degree of nano-osseointegration in two- and three-dimensions. HRTEM indicated the laser-modified surface encouraged the formation of crystalline hydroxyapatite in the immediate vicinity of the implant. Analytical studies suggested the presence of a functionally graded interface at the implant surface, characterized by the gradual intermixing of bone with oxide layer. Yet, the most compelling of techniques, which enabled straightforward visualization of nano-osseointegration, proved to be segmentation of electron tomographic reconstructions, where thresholding techniques identified bone penetrating into the nanoscale roughened surface features of laser-modified titanium. Combining high-resolution, analytical and three-dimensional electron microscopy techniques has proven to encourage identification and understanding of nano-osseointegration.

  • 12.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    McNally, E. A.
    Palmquist, A.
    Botton, G. A.
    Thomsen, P.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Visualizing biointerfaces in three dimensions: electron tomography of the bone-hydroxyapatite interface2010In: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 7, no 51, p. 1497-501Article in journal (Refereed)
    Abstract [en]

    A positive interaction between human bone tissue and synthetics is crucial for the success of bone-regenerative materials. A greater understanding of the mechanisms governing bone-bonding is often gained via visualization of the bone-implant interface. Interfaces to bone have long been imaged with light, X-rays and electrons. Most of these techniques, however, only provide low-resolution or two-dimensional information. With the advances in modern day transmission electron microscopy, including new hardware and increased software computational speeds, the high-resolution visualization and analysis of three-dimensional structures is possible via electron tomography. We report, for the first time, a three-dimensional reconstruction of the interface between human bone and a hydroxyapatite implant using Z-contrast electron tomography. Viewing this structure in three dimensions enabled us to observe the nanometre differences in the orientation of hydroxyapatite crystals precipitated on the implant surface in vivo versus those in the collagen matrix of bone. Insight into the morphology of biointerfaces is considerably enhanced with three-dimensional techniques. In this regard, electron tomography may revolutionize the approach to high-resolution biointerface characterization.

  • 13.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, A.
    Emanuelsson, L.
    Slotte, C.
    Adolfsson, E.
    Botton, G.
    Thomsen, P.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bone Regeneration in Hydroxyapatite Scaffolds: An in-vivo study in humans2009In: 22nd European Society for Biomaterials, Lausanne, Switzerland; 7-11th of September 2009, 2009Conference paper (Refereed)
  • 14.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Botton, Gianluigi
    Thomsen, Peter
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Electron tomography: A tool for the study of osseointegration in 3D.2011In: Scandanavian Society for Biomaterials 4th Annual Meeting, 2011Conference paper (Refereed)
  • 15.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    High-resolution three-dimensional probes of biomaterials and their interfaces2012In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 370, no 1963, p. 1337-1351Article in journal (Refereed)
    Abstract [en]

    Interfacial relationships between biomaterials and tissues strongly influence the success of implant materials and their long-term functionality. Owing to the inhomogeneity of biological tissues at an interface, in particular bone tissue, two-dimensional images often lack detail on the interfacial morphological complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar length scale. Electron tomography (ET) can meet these challenges by enabling high-resolution three-dimensional imaging of biomaterial interfaces. In this article, we review the fundamentals of ET and highlight its recent applications in probing the three-dimensional structure of bioceramics and their interfaces, with particular focus on the hydroxyapatite-bone interface, titanium dioxide-bone interface and a mesoporous titania coating for controlled drug release.

  • 16.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Three-dimensional structure of laser-modified Ti6Al4V and bone interface revealed with STEM tomography2011In: Frontiers in Electron Microscopy in Materials Science, 2011Conference paper (Refereed)
    Abstract [en]

    The Ti6Al4V titanium alloy is one of the most routinely used materials in implant technologies. It is a suitable biomaterial due to its intrinsic mechanical properties, the excellent biocompatibility of its native surface titanium-dioxide layer, and its ability to osseointegrate. The early interaction between an implant’s surface and bone is a leading factor for implant success, where multiple surface properties contribute to improved bone anchorage. An important parameter is surface topography, both on the micron and nanoscale. Laser-modification has been performed in the thread valleys of Ti6Al4V screws to alter their surface chemistry and topography to form a nanostructured surface titanium-dioxide. Since the valley regions are associated with increased bone formation kinetics and influential to implant bonding, the modified screws may exhibit enhanced bone attachment. In order to understand the underlying mechanisms and structure of the interface to nanostructured implant surfaces, characterization techniques with sufficient resolution are needed. Z-contrast electron tomography offers the possibility to explore the interfacial structure with high-resolution in three-dimensions. Furthermore, by operating in STEM mode, artifacts arising from diffraction contrast in the crystalline implant are avoided, while a high-degree of compositional contrast is maintained in the bone matrix. The aim of the present paper was to evaluate Z-contrast electron tomography as a tool to analyze the bone interface to a nanostructured implant surface. Implants were placed in the rabbit tibia and removed with surrounding bone after 8 weeks. Focused ion beam (FIB) was used to prepare specimens for transmission electron microscopy (TEM). Elemental analysis with energy dispersive x-ray spectroscopy (EDXS) over the implant-bone interface confirms the intermixing of bone apatite and titanium dioxide. This was further substantiated with three-dimensional reconstructions created from Z-contrast electron tomograms. Collagen fibers of the surrounding bone appear to have been laid down parallel to the implant surface. Accordingly, visualization of the laser-modified interface with nanoscale three-dimensional resolution, as offered by Z-contrast electron tomography, gives new insights into bone bonding mechanisms between roughened titanium-dioxide surfaces and bone.

  • 17.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Three-dimensional structure of laser-modified Ti6Al4V and bone interface revealed with STEM tomography2013In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 127, p. 48-52Article in journal (Refereed)
    Abstract [en]

    The early interaction between an implant's surface and bone is a leading factor for implant success, where multiple surface properties contribute to improved bone anchorage. An important parameter is surface topography, both on the micron and nanoscale. Laser-modification has been performed in the thread valleys of Ti6Al4V screws to alter their surface chemistry and topography to form a nanostructured surface titanium-dioxide. Implants were placed in the rabbit tibia, removed with surrounding bone after 8 weeks, fixated, dried and resin embedded. Focused ion beam milling (FIB) was used to prepare specimens from the resin blocks for transmission electron microscopy (TEM). Z-contrast electron tomography offered the possibility to explore the interfacial structure with high-resolution in three-dimensions. With this technique, collagen fibers of the surrounding bone appear to have been laid down parallel to the implant surface. Accordingly, visualization of the laser-modified interface with nanoscale three-dimensional resolution, as offered by Z-contrast electron tomography, gives new insights into bone bonding mechanisms between roughened titanium-dioxide surfaces and bone.

  • 18.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Dept of Biomaterias, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Thomsen, Peter
    Dept of Biomaterias, Sahlgrenska Academy at University of Gothenburg, Göteborg, och BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg.
    Resolving the CaP-bone interface: A review of discoveries with light and electron microscopy2012In: Biomatter, ISSN 2159-2527, Vol. 2, no 1, p. 15-23Article in journal (Refereed)
  • 19.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Institute for Clinical Sciences, Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Ericsson, Fredric
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Malmström, Johan
    Institute for Clinical Sciences, Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Emanuelsson, Lena
    Institute for Clinical Sciences, Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Slotte, Christer
    Institute for Clinical Sciences, Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg och Dept of Periodontology, The Institute for Postgraduate Dental Education, Jönköping.
    Adolfsson, Erik
    Swedish Ceramic Institute, IVF, Mölndal.
    Botton, Gianluigi A.
    Dept of Materials Science and Engineering, McMasters Unviersity, Hamilton, ON, Kanada.
    Thomsen, Peter
    Institute for Clinical Sciences, Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Bone response to free form fabricated hydroxyapatite and zirconia scaffolds: a transmission electron microscopy study in the human maxilla2012In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 14, no 3, p. 461-469Article in journal (Refereed)
    Abstract [en]

    Background: Understanding the interfacial reactions to synthetic bone regenerative scaffolds in vivo is fundamental for improving osseointegration and osteogenesis. Using transmission electron microscopy, it is possible to study the biological response of hydroxyapatite (HA) and zirconia (ZrO2) scaffolds at the nanometer scale.

    Purpose: In this study, the bone-bonding abilities of HA and ZrO2 scaffolds produced by free-form fabrication were evaluated in the human maxilla at 3 months and 7 months.

    Materials and Methods: HA and ZrO2 scaffolds (ø: 3 mm) were implanted in the human maxilla, removed with surrounding bone, embedded in resin, and sectioned. A novel focused ion beam (FIB) sample preparation technique enabled the production of thin lamellae for study by scanning transmission electron microscopy.

    Results: Interface regions were investigated using high-angle annular dark-field imaging and energy-dispersive X-ray spectroscopy analysis. Interfacial apatite layers of 80 nm and 50 nm thickness were noted in the 3- and 7-month HA samples, respectively, and bone growth was discovered in micropores up to 10 µm into the samples.

    Conclusions: The absence of an interfacial layer in the ZrO2 samples suggest the formation of a direct contact with bone, while HA, which bonds through an apatite layer, shows indications of resorption with increasing implantation time. This study demonstrates the potential of HA and ZrO2 scaffolds for use as bone regenerative materials.

  • 20.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Palmquist, Anders
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Göteborg.
    Goncalves, Stephane
    Teknimed S.A., Vic en Bigorre, Frankrike.
    Taylor, Andy
    Finsbury Development Ltd, Leatherhead, UK.
    Taylor, Mark
    Pera, Melton Mowbray, UK.
    Emanuelsson, Lena
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Göteborg.
    Thomsen, Peter
    Dept of Biomaterials, Sahlgrenska Academy, University of Gothenburg, and, Institute for Biomaterials and cell Therapy (IBCT), Göteborg.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Free form fabricated features on CoCr implants with and without hydroxyapatite coating in vivo: a comparative study of bone contact and bone growth induction2011In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 22, no 4, p. 899-906Article in journal (Refereed)
    Abstract [en]

    The current study evaluates the in vivo response to free form fabricated cobalt chromium (CoCr) implants with and without hydroxyapatite (HA) plasma sprayed coatings. The free form fabrication method allowed for integration of complicated pyramidal surface structures on the cylindrical implant. Implants were press fit into the tibial metaphysis of nine New Zealand white rabbits. Animals were sacrificed and implants were removed and embedded. Histological analysis, histomorphometry and electron microscopy studies were performed. Focused ion beam was used to prepare thin sections for high-resolution transmission electron microscopy examination. The fabricated features allowed for effective bone in-growth and firm fixation after 6 weeks. Transmission electron microscopy investigations revealed intimate bone-implant integration at the nanometre scale for the HA coated samples. In addition, histomorphometry revealed a significantly higher bone contact on HA coated implants compared to native CoCr implants. It is concluded that free form fabrication in combination with HA coating improves the early fixation in bone under experimental conditions.

  • 21.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pujari, Shiuli
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Effect of Calcium and Strontium on Mesoporous Titania Coatings for Implant Applications2013In: Journal of Biomaterials and Nanobiotechnology, ISSN 2158-7027, E-ISSN 2158-7043, Vol. 4, no 2, p. 107-113Article in journal (Refereed)
    Abstract [en]

    ncreasing interest in the role of ions such as calcium and strontium in bone formation has called for the investigation of multifunctional ion-doped implant coatings. Mesoporous titania coatings incorporating calcium or strontium enabled a unique pore morphology and potential for drug delivery. Coatings were produced on titanium by an evaporation induced self-assembly method with the addition of calcium or strontium to the sol causing a shift in morphology from a hexagonally-packed to a worm-like porous network. Pore sizes ranged from 3.8 - 5 nm and coatings exhibited high surface areas between 181 - 215.5 m2/g, as measured by N2adsorption-desorption. Coatings were loaded with 1 mg/ml Cephalothin, and showed sustained release of the antibiotic over one week in vitro. Cell studies confirmed that the ion addition had no toxic effect on human-like osteoblastic SaOS-2 cells. The results of this study suggest the potential for mesoporous coatings with calcium or strontium incorporation for direct bone-interfacing and combined drug delivery implant applications.

  • 22.
    Grandfield, Kathryn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pujari, Shiuli
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mesoporous titania implant coatings with and without calcium and strontium ion incorporation2012Conference paper (Refereed)
  • 23. Lee, Bryan
    et al.
    Samantha, Ho
    Gemma, Mestres
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Marjam, Karlsson Ott
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Philip, Koshy
    Kathryn, Grandfield
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Dual-Topography Electric Discharge Machining of Titanium to Improve Biocompatibility2016In: Surface and Coatings Technology, ISSN 0257-8972, Vol. 296, p. 149-156Article in journal (Refereed)
    Abstract [en]

    Surface modifications of titanium are widespread in an effort to improve the osseointegration capabilities of the metal for orthopaedic and dental applications. Here, electrical discharge machining (EDM) was used to create modified, notably, dual-topography surfaces on titanium. By swapping conventional copper electrodes for a titanium electrode and water dielectric, modified surfaces free of trace element contaminants were produced. Three surfaces were produced by varying the peak currents at 10 A, 29 A and a uniquely hierarchical multi current combination of 29 A followed by 2.4 A. The physicochemical properties of these surfaces were analyzed by scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and Auger Spectroscopy. These revealed the topography of the modified surfaces and a titanium oxide layer that was markedly thicker on the EDM samples compared to controls. In vitro cell testing was carried out with osteoblast-like MC3T3-E1 cells. Cell differentiation was increased in all EDM modified surfaces compared to controls and early differentiation was promoted on the dual-topography surface. The present study suggests the promise of dual-topography surfaces created using EDM for implant applications.

  • 24.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pettersson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Teuscher, Nico
    Fraunhofer, Institute for Mechanics of Material.
    Heilmann, Andreas
    Fraunhofer, Institute for Mechanics of Material.
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fabrication and evaluation of SixNy coatings for total joint replacements2012In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 23, no 8, p. 1879-1889Article in journal (Refereed)
    Abstract [en]

    Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si3N4 is a potential wear resistant alternative for total joint replacements. In this study, SixNy-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si3N4 similar to that found for bulk Si3N4. The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved.

  • 25.
    Palmquist, Anders
    et al.
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg .
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norlindh, Birgitta
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg .
    Mattson, Torsten
    Uppsala Oral and Maxillofacial Centre, Uppsala.
    Brånemark, Rickard
    Dept of Orthopaedics, Sahlgrenska University Hospital, Göteborg.
    Thomsen, Peter
    Dept of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg .
    Bone-titanium oxide interface in humans revealed by transmission electron microscopy and electron tomography2012In: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 9, no 67, p. 396-400Article in journal (Refereed)
    Abstract [en]

    Osseointegration, the direct contact between an implant surface and bone tissue, plays a critical role in interfacial stability and implant success. Analysis of interfacial zones at the micro- and nano-levels is essential to determine the extent of osseointegration. In this paper, a series of state-of-the-art microscopy techniques are used on laser-modified implants retrieved from humans. Partially laser-modified implants were retrieved after two and a half months' healing and processed for light and electron microscopy. Light microscopy showed osseointegration, with bone tissue growing both towards and away from the implant surface. Transmission electron microscopy revealed an intimate contact between mineralized bone and the laser-modified surface, including bone growth into the nano-structured oxide. This novel observation was verified by three-dimensional Z-contrast electron tomography, enabling visualization of an apatite layer, with different crystal direction compared with the apatite in the bone tissue, encompassing the nano-structured oxide. In conclusion, the present study demonstrates the nano-scale osseointegration and bonding between apatite and surface-textured titanium oxide. These observations provide novel data in human specimens on the ultrastructure of the titanium–bone interface.

  • 26.
    Thersleff, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Kenneth
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Structural characterization of mesoporous titania containing silver nanoparticle inclusions for antibacterial implant applications2012In: Proceedings of the 15th European Microscopy Congress: Volume 1: Physical Sciences: Applications / [ed] D. J. Stokes and W. M. Rainforth, 2012, p. 665-666Conference paper (Refereed)
  • 27.
    Thersleff, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Kenneth
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Structural characterization of mesoporous titania containing silver nanparticle inclusions for antibacterial implant applications2012In: Scandinavian Society for Biomaterials 5th Annual meeting, Uppsala, Sweden, May 8-9, 2012, 2012Conference paper (Refereed)
  • 28. Vuong, Vicky
    et al.
    Pettersson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Larsson, Sune
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Orthopaedics.
    Grandfield, Kathryn
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals2016In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 44, no 5, p. 1685-1697Article in journal (Refereed)
    Abstract [en]

    Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation.

  • 29.
    Xia, Wei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ballo, Ahmed
    Gothenburg University.
    Lausmaa, Jukka
    SP.
    Thomsen, Peter
    Gothenburg University.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Well-ordered mesoporous titanium dioxide coating for metallic implants2011In: ORS 2011 (USA), 2011Conference paper (Refereed)
  • 30.
    Xia, Wei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Hoess, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ballo, Ahmed
    BIOMATCELL, VINN excellence Center of Biomaterials and Cell Therapy, Göteborg, Dept of Biomaterials, Institute for Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Göteborg.
    Cai, Yanling
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mesoporous titanium dioxide coating for metallic implants2012In: Journal of Biomedical Materials Research. Part B - Applied biomaterials, ISSN 1552-4973, E-ISSN 1552-4981, Vol. 100B, no 1, p. 82-93Article in journal (Refereed)
    Abstract [en]

    A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self-assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m2/g and average pore diameter of 4.3 nm. Adhesion tests using the scratch method and an in situ screw-in/screw-out technique confirm that the MT coating bonds tightly with the metallic substrate, even after removal from bone. Because of its high surface area, the bioactivity of the MT coating is much better than that of a dense TiO2 coating of the same composition. Quick formation of hydroxyapatite (HA) in vitro can be related to enhance bonding with bone. The uptake of antibiotics by the MT coating reached 13.4 mg/cm3 within a 24 h loading process. A sustained release behavior has been obtained with a weak initial burst. By using Cephalothin as a model drug, drug loaded MT coating exhibits a sufficient antibacterial effect on the material surface, and within millimeters from material surface, against E.coli. Additionally, the coated and drug loaded surfaces showed no cytotoxic effect on cell cultures of the osteoblastic cell line MG-63. In conclusion, this study describes a novel, biocompatiblemesoporous implant coating, which has the ability to induce HA formation and could be used as a surface drug-delivery system.

  • 31.
    Xia, Wei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Schwenke, Almut
    Institute of Materials Science and Technology, Jena, Tyskland.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Synthesis and release of trace elements from hollow and porous hydroxyapatite spheres2011In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 22, no 30, p. 305610-Article in journal (Refereed)
    Abstract [en]

    It is known that organic species regulate fabrication of hierarchical biological forms via solution methods. However, in this study, we observed that the presence of inorganic ions plays an important role in the formation and regulation of biological spherical hydroxyapatite formation. We present a mineralization method to prepare ion-doped hydroxyapatite spheres with a hierarchical structure that is free of organic surfactants and biological additives. Porous and hollow strontium-doped hydroxyapatite spheres were synthesized via controlling the concentration of strontium ions in a calcium and phosphate buffer solution. Similarly, fluoride and silicon-doped hydroxyapatite spheres were synthesized. While spherical particle formation was attainable at low and high temperature for Sr-doped hydroxyapatite, it was only possible at high temperature in the F/Si-doped system. The presence of inorganic ions not only plays an important role in the formation and regulation of biological spherical hydroxyapatite, but also could introduce pharmaceutical effects as a result of trace element release. Such ion release results showed a sustained release with pH responsive behavior, and significantly influenced the hydroxyapatite re-precipitation. These ion-doped hydroxyapatite spheres with hollow and porous structure could have promising applications as bone/tooth materials, drug delivery systems, and chromatography supports.

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