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Hanitsch S.,TU Ilmenau | Grohmann S.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Berg A.,Innovent Jena | Moje J.,Moje Implantate GmbH and Co. KG | Hoffmann M.,TU Ilmenau
Biomedizinische Technik | Year: 2014

For the integration of sensor components into ceramic-based implants it is of importance to create a reliable sensortissue interface. But an implantable sensor interface requires a set of properties: Such as biocompatibility, antifouling properties bio-stability and ion permeability. Hydrogels in general have promising qualities towards an application in this context. To screen different hydrogel coatings a method is needed which allows testing a broad range of materials in relation to the implants' other components. This is not always possible at an early stage of research. Therefore a test chip was developed enabling a parallel screening of hydrogel sensor coatings towards bio interaction and the testing of technically relevant properties using implant material. © 2014 by Walter de Gruyter Berlin Boston.

Visaveliya N.,TU Ilmenau | Hoffmann C.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Hoffmann C.,Sartorius Stedim Biotech GmbH | Gross A.,TU Ilmenau | And 3 more authors.
Nanotechnology Reviews | Year: 2016

Numerous different photonics and biomedical applications depend on the fluorescent polymer micro- and nanoparticles. Besides optical or spectroscopic properties, the performance of the polymer nanoparticles is determined by their size, size distribution, and surface charge. Moreover, in order to realize a very uniform performance, the functional polymer nanoparticles should be of high homogeneity and demand for the preparation in a minimum number of synthesis steps. Here, we present a microfluidic-assisted synthesis of different types of reproducible fluorescent polymer nanoparticles with tuned size (40 nm up to 600 nm) and surface charge (ζ potential=-52 mV up to +45 mV). Four different preparation strategies were introduced for fluorophore-functionalized nanoparticles: (a) noncovalent binding of fluorophores with high loading, (b) covalent linking of fluorophores with enhanced stability, (c) surface-anchored fluorophores by hydrophobic interactions for triple function at the same time, and (d) surface immobilization of biomolecules and fluorophore by ionic as well as secondary interactions. In this way, four different classes of nanoparticles suited for different applications were prepared with a spherical shape as a model system. Moreover, the principle has been extended to the different types of nonspherical and composite polymer nanoparticles. © 2016 by De Gruyter.

Schmitt K.,Fraunhofer Institute for Physical Measurement Techniques | Rist J.,Fraunhofer Institute for Physical Measurement Techniques | Hoffmann C.,Institute for Bioprocessing and Analytical Measurement Techniques iba
Analytical and Bioanalytical Chemistry | Year: 2011

Functional surfaces and especially the control of surface properties depending on external parameters such as light illumination have gained increasing importance in the last few years. We present the characterization of polymers from the cycloolefin (co)polymer class (COC/COP) functionalized with an aminosilane as a basis for the further immobilization of compounds. In a first step, an assay using AlexaFluor®647 fluorescent dye was used to assess surface homogeneity and reproducibility. A coefficient of variation of less than 15% for dot-to-dot and less than 25% for chip-to-chip could be achieved. The same amino-functionalized surfaces were then used to immobilize a biotinylated photolabile linker compound, binding AlexaFluor®647-labeled streptavidin. The linker was photocleaved with high efficiency at λ∈=∈365 nm and P∈=∈0.15 mW/cm 2. Fluorescence measurements show that polymers of the COC/COP class can be used as versatile surfaces for the photoinduced release of compounds immobilized via photolabile linkers. [Figure not available: see fulltext.] © 2011 Springer-Verlag.

Schade R.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Sikiric M.D.,Ruder Boskovic Institute | Lamolle S.,University of Oslo | Ronold H.J.,University of Oslo | And 4 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2010

Recently described organic-inorganic nanocomposite coatings of the chemical composition: (PLL/PGA)10CaP[(PLL/PGA)5CaP]4 (coating A) and (PLL/PGA)10CaP[(PLL/PGA)5CaP] 4(PLL/PGA)5 (coating B), applied to chemically etched titanium plates, have been tested by extensive cell culture tests and in vivo biological experiments, with uncoated titanium plates serving as controls. Before testing, coated samples were stored for extended periods of time (from 2 weeks to 8 months) under dry, sterile conditions. Cells of the cell-lines MC3T3-E1 and/or SAOS-2 were used for the following cell culture tests: initial adhesion (4 h) and proliferation (up to 21 days), cell activity (XTT test), morphology, synthesis of collagen type I and alkaline phosphatase activity (all incubation up to 21 days). In addition, coating B was tested against uncoated control in a validated in vivo pull-out model in rabbit tibia. The results of both in vitro and in vivo experiments show excellent biological properties of chemically etched titanium which are even surpassed by surfaces covered with coating B. Thus, after 8 weeks of healing the implants coated with B were significantly better attached to the cortical bone of rabbit thibiae than uncoated titanium controls with more than twice the force needed to detach coated implants. However, coating A (top crystal layer) had an adverse effect on both cell proliferation and activity, which is explained by morphological observations, showing inhibited spreading of the cells on its rough surfaces. The results also show the remarkable stability of the coatings when shelved under dry and sterile conditions. © 2010 Wiley Periodicals, Inc.

Grohmann S.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Rothe H.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Frant M.,Institute for Bioprocessing and Analytical Measurement Techniques iba | Liefeith K.,Institute for Bioprocessing and Analytical Measurement Techniques iba
Biomacromolecules | Year: 2011

To promote osteoblast adhesion and proliferation on (bio)material surfaces, biomimetic coatings resembling the natural extracellular matrix (ECM) are desirable. The glycosamino glycans (GAGs) chondroitin sulfate (CS) and heparin (HEP) are promising candidates for a biomimetic coating since they are two of the most prevalent noncollagenous biomolecules constituting the ECM. Coatings containing CS and HEP were prepared employing the "layer by layer" technique yielding polyelectrolyte multilayers (PEMs). Physicochemical and mechanical characterization of the coatings were performed by means of streaming potential measurements and colloidal force spectroscopy. The capability of the coatings to support cell adhesion, spreading, proliferation, and maintenance of an osteoblastic phenotype was assessed with SaOS osteosarcoma cells. We demonstrate that PEMs constructed from CS as the polyanion display a low Young's modulus correlated with poorly supported cell adhesion and proliferation. When the CS was adsorbed onto a stiffer polypeptide PEM basis, the Young's modulus increased, and the cell response was significantly improved. For HEP coatings an intermediate Young's modulus and moderate cell adhesion and spreading were observed. No significant changes in stiffness or cell response were detected when HEP was adsorbed onto the polypeptide film. © 2011 American Chemical Society.

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