Thomas Doert

Proliferation, differentiation and gene expression of osteoblasts in boron-containing associated with dexamethasone deliver from mesoporous bioactive glass scaffolds.

Boron is one of the trace elements in the human body which plays an important role in bone growth. Porous mesopore bioactive glass (MBG) scaffolds are proposed as potential bone regeneration materials due to their excellent bioactivity and drug-delivery ability. The aims of the present study were to develop boron-containing MBG (B-MBG) scaffolds by sol-gel method and to evaluate the effect of boron on the physiochemistry of B-MBG scaffolds and the response of osteoblasts to these scaffolds. Furthermore, the effect of dexamethasone (DEX) delivery in B-MBG scaffold system was investigated on the proliferation, differentiation and bone-related gene expression of osteoblasts. The composition, microstructure and mesopore properties (specific surface area, nano-pore volume and nano-pore distribution) of B-MBG scaffolds have been characterized. The effect of boron contents and large-pore porosity on the loading and release of DEX in B-MBG scaffolds were also investigated. The results have shown that the incorporation of boron into MBG scaffolds slightly decreases the specific surface area and pore volume, but maintains well-ordered mesopore structure and high surface area and nano-pore volume compared to non-mesopore bioactive glass. Boron contents in MBG scaffolds did not influence the nano-pore size distribution or the loading and release of DEX. B-MBG scaffolds have the ability to maintain a sustained release of DEX in a long-term span. Incorporating boron into MBG glass scaffolds led to a controllable release of boron ions and significantly improved the proliferation and bone-related gene expression (Col I and Runx2) of osteoblasts. Furthermore, the sustained release of DEX from B-MBG scaffolds significantly enhanced alkaline phosphatase (ALP) activity and gene expressions (Col I, Runx2, ALP and BSP) of osteoblasts. These results suggest that boron plays an important role in enhancing osteoblast proliferation in B-MBG scaffold system and DEX-loaded B-MBG scaffolds show great potential as a release system to enhance osteogenic property for bone tissue engineering application.

Bioactive SrO–SiO2 glass with well-ordered mesopores: Characterization, physiochemistry and biological properties

For a biomaterial to be considered suitable for bone repair it should ideally be both bioactive and have a capacity for controllable drug delivery; as such, mesoporous SiO(2) glass has been proposed as a new class of bone regeneration material by virtue of its high drug-loading ability and generally good biocompatibility. It does, however, have less than optimum bioactivity and controllable drug delivery properties. In this study, we incorporated strontium (Sr) into mesoporous SiO(2) in an effort to develop a bioactive mesoporous SrO-SiO(2) (Sr-Si) glass with the capacity to deliver Sr(2+) ions, as well as a drug, at a controlled rate, thereby producing a material better suited for bone repair. The effects of Sr(2+) on the structure, physiochemistry, drug delivery and biological properties of mesoporous Sr-Si glass were investigated. The prepared mesoporous Sr-Si glass was found to have an excellent release profile of bioactive Sr(2+) ions and dexamethasone, and the incorporation of Sr(2+) improved structural properties, such as mesopore size, pore volume and specific surface area, as well as rate of dissolution and protein adsorption. The mesoporous Sr-Si glass had no cytotoxic effects and its release of Sr(2+) and SiO(4)(4-) ions enhanced alkaline phosphatase activity - a marker of osteogenic cell differentiation - in human bone mesenchymal stem cells. Mesoporous Sr-Si glasses can be prepared to porous scaffolds which show a more sustained drug release. This study suggests that incorporating Sr(2+) into mesoporous SiO(2) glass produces a material with a more optimal drug delivery profile coupled with improved bioactivity, making it an excellent material for bone repair applications.

LaSe1.85, CeSe1.83, NdSe1.83 and SmSe1.84 - four new rare earth metal polyselenides with incommensurate site occupancy and displacive modulation

Abstract Crystals of the four new binary rare earth metal polyselenides LaSe1.85, CeSe1.83, NdSe1.83 and SmSe1.84 were obtained by flux reactions. Their two-dimensionally incommensurately modulated structures were solved from X-ray diffraction data. Structure models were established in super space group X4/n(–αβ0)(βα0)00 with modulation wave vectors q1 = –αa* + βb* and q2 = βa* + αb* and the centering vector (0, 0, 1/2, 1/2, 1/2). The unit cell parameters at T = 293 K are a = 4.216(1) Å and c = 17.048(2) Å for LaSe1.85, a = 4.178(1) Å and c = 16.942(3) Å for CeSe1.83, a = 4.123(1) Å and c = 16.792(2) Å for NdSe1.83 and a = 4.080(1) Å and c = 16.672(2) Å for SmSe1.84; the components of the modulation wave vectors are α = β = 0.292(1) for LaSe1.85 and CeSe1.83, and α = β = 0.293(1) for NdSe1.83 and SmSe1.84, respectively. The modulation originates from a site occupancy wave caused by defects in planar selenium layers coupled to a displacive modulation.

Magnetic, electrical resistivity, heat-capacity, and thermopower anomalies in CeCuAs2

The results of magnetic susceptibility

Pb⋯X (X = N, S, I) tetrel bonding interactions in Pb(II) complexes: X-ray characterization, Hirshfeld surfaces and DFT calculations

(\ensuremath{\chi})

Structural Frustration and Occupational Disorder: The Rare Earth Metal Polysulfides Tb8S14.8, Dy8S14.9, Ho8S14.9, and Y8S14.8

, electrical resistivity

High-pressure synthesis of rare-earth metal disulfidesand diselenides LnX2 (Ln = Sm, Gd, Tb, Dy, Ho, Er and Tm; X = S, Se)

(\ensuremath{\rho})

Lanthanoiddisulfide – Synthesen und Kristallstrukturen von α-CeS2, α-NdS2, β-LaS2, β-CeS2 und β-PrS2 / Rare Earth Metal Disulfides – Syntheses and Crystal Structures of α-CeS2, α-NdS2, β -LaS2, β -CeS2, and β -PrS2

, heat-capacity

Anion-driven tetrel bond-induced engineering of lead(II) architectures with N′-(1-(2-pyridyl)ethylidene)nicotinohydrazide: experimental and theoretical findings

(C)

Resource-Efficient High-Yield Ionothermal Synthesis of Microcrystalline Cu3–xP

, and thermopower