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Biomineralization on Single Crystalline Rutile: The Modulated Growth of Hydroxyapatite by Fibronectin in a Simulated Body Fluid
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Electron microscopy and Nanoengineering)ORCID iD: 0000-0003-1050-8441
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Electron microscopy and Nanoengineering)
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2016 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, 35507-35516 p.Article in journal (Refereed) Published
Abstract [en]

The aim of this study is to probe the complex interaction between surface bioactivity and protein adsorption on single crystalline rutile. Our previous studies have shown that single crystalline rutile possessed in vitro bioactivity and the crystalline faces affected the hydroxyapatite (HA) formation. However, upon implantation, a fast adsorption of proteins, from the biological fluids, is intermediated by a water layer towards the biomaterial interface. Thus the effect of protein on the bioactivity must be addressed. In this study, the HA growth dynamics on (001), (100) and (110) faces was investigated in a simulated body fluid with the presence of fibronectin (FN) by two different processes. The surface adhesion of each face before and after FN adsorption, as revealed by direct numerical values, was determined by atomic force microscopy (AFM) based peak force quantitative nanomechanical mapping (PF-QNM) for the first time. The findings suggest the surface energies of FN pre-adsorbed (001), (100) and (110) faces have been enhanced, leading to the subsequent accelerated HA formation. Furthermore, (001) and (100) faces were found to have larger coverage of HA crystals than (110) face at an early stage. In addition, various characterizations were performed to probe the chemical and crystal structures of as-grown biomimetic HA crystals, and in particular, the Ca/P ratio variations at different soaking time points.

Place, publisher, year, edition, pages
2016. Vol. 6, 35507-35516 p.
National Category
Engineering and Technology Materials Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-277120DOI: 10.1039/C6RA04303HISI: 000374349600042OAI: oai:DiVA.org:uu-277120DiVA: diva2:903912
Available from: 2016-02-17 Created: 2016-02-17 Last updated: 2017-11-30Bibliographically approved
In thesis
1. Bio-Nano Interactions: Synthesis, Functionalization and Characterization of Biomaterial Interfaces
Open this publication in new window or tab >>Bio-Nano Interactions: Synthesis, Functionalization and Characterization of Biomaterial Interfaces
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Current strategies for designing biomaterials involve creating materials and interfaces that interact with biomolecules, cells and tissues.  This thesis aims to investigate several bioactive surfaces, such as nanocrystalline diamond (NCD), hydroxyapatite (HA) and single crystalline titanium dioxide, in terms of material synthesis, surface functionalization and characterization.

Although cochlear implants (CIs) have been proven to be clinically successful, the efficiency of these implants still needs to be improved. A CI typically only has 12-20 electrodes while the ear has approximately 3400 inner hair cells. A type of micro-textured NCD surface that consists of micrometre-sized nail-head-shaped pillars was fabricated. Auditory neurons showed a strong affinity for the surface of the NCD pillars, and the technique could be used for neural guidance and to increase the number of stimulation points, leading to CIs with improved performance.

Typical transparent ceramics are fabricated using pressure-assisted sintering techniques. However, the development of a simple energy-efficient production method remains a challenge. A simple approach to fabricating translucent nano-ceramics was developed by controlling the morphology of the starting ceramic particles. Translucent nano-ceramics, including HA and strontium substituted HA, could be produced via a simple filtration process followed by pressure-less sintering. Furthermore, the application of such materials as a window material was investigated. The results show that MC3T3 cells could be observed through the translucent HA ceramic for up to 7 days. The living fluorescent staining confirmed that the MC3T3 cells were visible throughout the culture period.

Single crystalline rutile possesses in vitro bioactivity, and the crystalline direction affects HA formation. The HA growth on (001), (100) and (110) faces was investigated in a simulated body fluid in the presence of fibronectin (FN) via two different processes. The HA layers on each face were analysed using different characterization techniques, revealing that the interfacial energies could be altered by the pre-adsorbed FN, which influenced HA formation.

In summary, micro textured NCD, and translucent HA and FN functionalized single crystalline rutile, and their interactions with cells and biomimetic HA were studied. The results showed that controlled surface properties are important for enhancing a material’s biological performance.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 37 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1345
Keyword
Bioactive surfaces, nanocrystalline diamond, hydroxyapatite, protein secondary structure, protein absorption, auditory neurons, single crystalline rutile, nano morphology, surface functionalisation, in vitro biomineralisation, translucent nano-ceramics, bio-window material, material characterisation.
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-277121 (URN)978-91-554-9478-0 (ISBN)
Public defence
2016-06-01, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2016-05-11 Created: 2016-02-17 Last updated: 2016-06-01
2. Covalent Graphene Functionalization for the Modification of Its Physical Properties
Open this publication in new window or tab >>Covalent Graphene Functionalization for the Modification of Its Physical Properties
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Graphene, a two dimensional monolayer carbon sheet with the atoms tightly packed in a hexagonal lattice, has exhibited so many excellent properties, which enable graphene to break several material records with regard to carrier mobility, strength yield and thermal conductivity to name a few. Therefore, graphene has been placed as a potential candidate to allow truly next-generation material. Graphene is a zero band gap material, implying that an energy band gap around the Dirac point is supposed to be open to make graphene applicable as a semiconductor. Covalent bond graphene functionalization becomes an essential enabler to open the energy gap in graphene and extend graphene applications in electronics, while the densely packed hexagonal carbon atoms as well as the strong sp2 hybridization carbon-carbon bonds jointly result in a changeling topic of allowing graphene to be decorated with functional groups.

Here in this thesis, different routes to realize graphene functionalizations are implemented by using physical and chemical ways. The physical functionalization methods are the ion/electron beam induced graphene fluorination as well as local defect insertion and the chemical ways correspond to the photochemistry techniques to approach hydrogenation and hydroxypropylation of graphene. Furthermore, to incorporate graphene into devices, the tuning of mechanical properties of graphene is desired. Towards this aim, the structure modification of graphene is employed to investigate the nanometer size-effect of crystalline size of graphene on the mechanical properties, namely Young’s modulus and surface energy. In the process of the graphene hydrogenation project, we discovered a high yield way to synthesis high quality graphene nanoscroll (GNS). Interestingly, the GNS shows superadhesion property through our atomic force microscopy measurements. This superadhesion is around 6-order stronger than van der Waals interaction and even higher than the hydrogen bonding enhanced and solid/liquid interfaces.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. 60 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1472
Keyword
graphene; functionalization; nanomechanical property, graphene nanoscroll
National Category
Materials Engineering Physical Sciences Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-314176 (URN)978-91-554-9807-8 (ISBN)
Public defence
2017-03-17, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 23:15 (English)
Opponent
Supervisors
Available from: 2017-02-24 Created: 2017-01-30 Last updated: 2017-02-24

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Cai, YixiaoLi, HuKarlsson, MikaelLeifer, KlausEngqvist, HåkanXia, Wei

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