TY  - JOUR
A1  - Straßer, Marion
A1  - Schrauth, Joachim H. X.
A1  - Dembski, Sofia
A1  - Haddad, Daniel
A1  - Ahrens, Bernd
A1  - Schweizer, Stefan
A1  - Christ, Bastian
A1  - Cubukova, Alevtina
A1  - Metzger, Marco
A1  - Walles, Heike
A1  - Jakob, Peter M.
A1  - Sextl, Gerhard
T1  - Calcium fluoride based multifunctional nanoparticles for multimodal imaging
JF  - Beilstein Journal of Nanotechnology
N2  - New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{−1}\)·s\(^{−1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{−1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging.
KW  - calcium fluoride nanoparticles
KW  - magnetic resonance imaging (MRI)
KW  - multifunctional nanoparticles
KW  - multimodal imaging
KW  - photoluminescence
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170657
VL  - 8
ER  - 
TY  - JOUR
A1  - Christ, Bastian
A1  - Glaubitt, Walther
A1  - Berberich, Katrin
A1  - Weigel, Tobias
A1  - Probst, Jörn
A1  - Sextl, Gerhard
A1  - Dembski, Sofia
T1  - Sol-gel-derived fibers based on amorphous α-hydroxy-carboxylate-modified titanium(IV) oxide as a 3-dimensional scaffold
JF  - Materials
N2  - The development of novel fibrous biomaterials and further processing of medical devices is still challenging. For instance, titanium(IV) oxide is a well-established biocompatible material, and the synthesis of TiO\(_x\) particles and coatings via the sol-gel process has frequently been published. However, synthesis protocols of sol-gel-derived TiO\(_x\) fibers are hardly known. In this publication, the authors present a synthesis and fabrication of purely sol-gel-derived TiO\(_x\) fiber fleeces starting from the liquid sol-gel precursor titanium ethylate (TEOT). Here, the α-hydroxy-carboxylic acid lactic acid (LA) was used as a chelating ligand to reduce the reactivity towards hydrolysis of TEOT enabling a spinnable sol. The resulting fibers were processed into a non-woven fleece, characterized with FTIR, \(^{13}\)C-MAS-NMR, XRD, and screened with regard to their stability in physiological solution. They revealed an unexpected dependency between the LA content and the dissolution behavior. Finally, in vitro cell culture experiments proved their potential suitability as an open-mesh structured scaffold material, even for challenging applications such as therapeutic medicinal products (ATMPs).
KW  - sol-gel chemistry
KW  - scaffold
KW  - dry spinning
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270694
SN  - 1996-1944
VL  - 15
IS  - 8
ER  -