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O. Winter:
"Synthesis, functionalization and application of templated mesoporous bioactive glasses";
Betreuer/in(nen), Begutachter/in(nen): D. Eder, H. Eckert; Institute of Physical Chemistry, Westfälische Wilhelms Universität, Münster, Germany, 2017; Rigorosum: 07.07.2017.

Mesoporous bioactive glasses (MBGs) are of high importance in the field of bone tissue engineering. Due to their excellent textural properties, e.g. high specific surface area and porosity, MBGs show several advantages compared with glasses prepared through the traditional non-template sol-gel route or a melt-quenching approach, such as an improved in-vitro bioactivity through the formation of a bonding layer of hydroxyapatite when immersed in a simulated body fluid (SBF). However, their low mechanical strength and pore diameters of only up to 10 nm in size are limitations for load-bearing applications or drug-delivery systems.
This work focused on the changes in morphology, in-vitro bioactivity and mechanical properties of different MBG series. For this, two different strategies were used: (a) the incorporation of two dopants, Al2O3 and B2O3, was used to address the challenge of the low mechanical properties and (b) the use of non-commercial ABC triblock terpolymers addressed the limitation of pore diameters in MBGs.
For the first strategy a MBG model system was developed, using the commercially available ABA triblock copolymer Pluronic® P123 as template. Through the incorporation of different amounts of Al2O3 and/or B2O3 to the SiO2-CaO-P2O5-MBG model system, four series of doped MBGs were prepared and characterized. The incorporation of Al2O3 showed a decrease in both order of the pore structure and in-vitro bioactivity with increasing contents of Al2O3. The mechanical properties for elasticity modulus and hardness of the non-doped MBG model system could be increased by Al2O3 incorporation. Through the incorporation of B2O3 the high order of the pore structure of the MBG model system could be maintained and B2O3-doped MBGs showed superior properties in terms of both in-vitro bioactivity and mechanical properties. In two series of Al2O3/B2O3 co-doped MBGs B2O3 showed the ability to partly compensate the negative influence of Al2O3 on morphology and in-vitro bioactivity.
Through a structure engineering approach using different ISO triblock terpolymers as templates ordered pore structures with large pore diameters up to 30 nm and 3D-network morphologies could be introduced into MBGs. First results showed a high in-vitro bioactivity and an improvement in the mechanical properties compared with a non-template bioactive sol-gel glass.
The results were supported by extensive materials characterization, including elec-tron microscopy (SEM, TEM), nitrogen adsorption (BET, BJH), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), solid-state nuclear magnetic resonance (NMR) spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES) and nanoindentation.