TY - JOUR A1 - Kagel, Heike A1 - Bier, Frank Fabian A1 - Frohme, Marcus A1 - Glökler, Jörn T1 - A Novel Optical Method To Reversibly Control Enzymatic Activity Based On Photoacids JF - Scientific Reports N2 - Most biochemical reactions depend on the pH value of the aqueous environment and some are strongly favoured to occur in an acidic environment. A non-invasive control of pH to tightly regulate such reactions with defined start and end points is a highly desirable feature in certain applications, but has proven difficult to achieve so far. We report a novel optical approach to reversibly control a typical biochemical reaction by changing the pH and using acid phosphatase as a model enzyme. The reversible photoacid G-acid functions as a proton donor, changing the pH rapidly and reversibly by using high power UV LEDs as an illumination source in our experimental setup. The reaction can be tightly controlled by simply switching the light on and off and should be applicable to a wide range of other enzymatic reactions, thus enabling miniaturization and parallelization through non-invasive optical means. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12685 SN - 2045-2322 VL - 9 ER - TY - JOUR A1 - Grebinyk, Anna A1 - Prylutska, Svitlana A1 - Grebinyk, Sergii A1 - Prylutskyy, Yuriy A1 - Ritter, Uwe A1 - Matyshevska, Olga A1 - Dandekar, Thomas A1 - Frohme, Marcus T1 - Complexation with C60 Fullerene Increases Doxorubicin Efficiency against Leukemic Cells In Vitro JF - Nanoscale Research Letters N2 - Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To address this problem, we have explored a C60 fullerene-based nanosized system as a carrier for anticancer drugs for an optimized drug delivery to leukemic cells. Here, we studied the physicochemical properties and anticancer activity of C60 fullerene noncovalent complexes with the commonly used anticancer drug doxorubicin. C60-Doxorubicin complexes in a ratio 1:1 and 2:1 were characterized with UV/Vis spectrometry, dynamic light scattering, and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The obtained analytical data indicated that the 140-nm complexes were stable and could be used for biological applications. In leukemic cell lines (CCRF-CEM, Jurkat, THP1 and Molt-16), the nanocomplexes revealed ≤ 3.5 higher cytotoxic potential in comparison with the free drug in a range of nanomolar concentrations. Also, the intracellular drug’s level evidenced C60 fullerene considerable nanocarrier function. The results of this study indicated that C60 fullerene-based delivery nanocomplexes had a potential value for optimization of doxorubicin efficiency against leukemic cells. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-11415 SN - 1556-276X VL - 14 ER - TY - JOUR A1 - Gossing, Wilhelm A1 - Frohme, Marcus A1 - Radke, Lars T1 - Biomarkers for Liquid Biopsies of Pituitary Neuroendocrine Tumors JF - Biomedicines N2 - Pituitary neuroendocrine tumors (PitNET) do not only belong to the most common intracranial neoplasms but seem to be generally more common than has been thought. Minimally invasive liquid biopsies have the potential to improve their early screening efficiency as well as monitor prognosis by facilitating the diagnostic procedures. This review aims to assess the potential of using liquid biopsies of different kinds of biomarker species that have only been obtained from solid pituitary tissues so far. Numerous molecules have been associated with the development of a PitNET, suggesting that it often develops from the cumulative effects of many smaller genetic or epigenetic changes. These minor changes eventually pile up to switch critical molecules into tumor-promoting states, which may be the key regulatory nodes representing the most potent marker substances for a diagnostic test. Drugs targeting these nodes may be superior for the therapeutic outcome and therefore the identification of such pituitary-specific cellular key nodes will help to accelerate their application in medicine. The ongoing genetic degeneration in pituitary adenomas suggests that repeated tumor profiling via liquid biopsies will be necessary for personalized and effective treatment solutions. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13307 SN - 2227-9059 VL - 8 IS - 6 ER - TY - JOUR A1 - Bauer, Joachim A1 - Gutke, Marko A1 - Heinrich, Friedhelm A1 - Edling, Matthias A1 - Stoycheva, Vesela A1 - Kaltenbach, Alexander A1 - Burkhardt, Martin A1 - Gruenefeld, Martin A1 - Gamp, Matthias A1 - Gerhard, Christoph A1 - Steglich, Patrick A1 - Steffen, Sebastian A1 - Herzog, Michael A1 - Dreyer, Christian A1 - Schrader, Sigurd T1 - Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses JF - Optical Materials Express N2 - In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13472 SN - 2159-3930 VL - 10 IS - 9 SP - 2085 EP - 2099 ER - TY - JOUR A1 - Goldenberg, Leonid A1 - Köhler, Mathias A1 - Kahle, Olaf A1 - Dreyer, Christian T1 - Impact of inorganic nanoparticles on optical properties of low refractive index waveguiding polymers JF - Optical Materials Express N2 - The objective of this work is to improve the optical properties of low refractive index polymers used for waveguide by introduction of inorganic nanoparticles. Copolymers of fluorinated monomers and glycidyl methacrylate are used. Introduction of SiO2 nanoparticles into polymer matrix is performed by direct mixing; copolymerization with SiO2 nanoparticles modified by monomer, and in situ sol-gel formation of SiO2 during photochemical cross-linking and annealing catalyzed by photoacid generator. It is demonstrated that nanoparticles are able to decrease thermo-optic coefficient. It is also possible to fabricate waveguiding layers by direct introduction of nanoparticles without compromising of optical propagation losses. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13521 SN - 2159-3930 VL - 10 IS - 11 SP - 2987 EP - 2997 ER - TY - JOUR A1 - Bondarenko, Siegfried A1 - Villringer, Claus A1 - Steglich, Patrick T1 - Comparative Study of Nano-Slot Silicon Waveguides Covered by Dye Doped and Undoped Polymer Cladding JF - Applied Sciences N2 - Nonlinear optical dyes doped in optical polymer matrices are widely used for electro-optical devices. Linear optical properties change with dye concentration, which leads to a change in modal properties, especially in nano-structured integrated waveguides such as silicon slot-waveguides. Here, we investigate the influence of a nonlinear optical dye on the performance of a silicon-organic hybrid slot-waveguide. A simulation study of the modal and optical confinement properties is carried out and dependence of the structural parameters of the slot-waveguide and the organic cladding material is taken into account. As cladding material, a guest-host polymer system is employed comprising the nonlinear optical dye Disperse Red 1 (DR1) doped in a poly[methyl methacrylate] (PMMA) matrix. The refractive indices of doped and undoped PMMA were deduced from ellipsometric data. We present a guideline for an optimized slot-waveguide design for the fabrication in silicon-on-insulator technology giving rise to scalable, high-performance integrated electro-optical modulators. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10716 SN - 2076-3417 VL - 9 IS - 1 PB - MDPI ER - TY - JOUR A1 - Lux, Helge A1 - Edling, Matthias A1 - Siemroth, Peter A1 - Schrader, Sigurd T1 - Fast and Cost-Effective Synthesis of High-Quality Graphene on Copper Foils Using High-Current Arc Evaporation JF - Materials N2 - In this paper, we present an innovative and ultra-fast process for the deposition of high-quality graphene on different metal foils and thin metal films. The graphene layer can be homogeneously deposited in only 30 s process time. Due to the weak adhesion to the substrate material, the monolayer graphene is easy to transfer using the established processes. For the production, we use magnetic filtered high-current arc evaporation (Φ-HCA) with a solid, graphitic carbon source. This ultra-fast growth process can pave the way towards a cost-effective graphene synthesis for the mass production e.g., in a roll-to-roll process, avoiding time consuming established processes. KW - graphene KW - PVD KW - arc evaporation KW - copper KW - transfer KW - Φ-HCA Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10359 SN - 1996-1944 VL - 11 IS - 5 SP - 1 EP - 10 ER - TY - JOUR A1 - Grebinyk, Anna A1 - Grebinyk, Sergii A1 - Prylutska, Svitlana A1 - Ritter, Uwe A1 - Matyshevska, Olga A1 - Dandekar, Thomas A1 - Frohme, Marcus T1 - HPLC-ESI-MS method for C60 fullerene mitochondrial content quantification JF - Data in Brief N2 - The presented dataset describes the quantification of carbon nanoparticle C60 fullerene accumulated in mitochondria of human leukemic cells treated with nanostructure. Firstly, the high performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC-ESI-MS) method was developed for quantitative analysis of pristine C60 fullerene. Then, human leukemic cells were incubated with C60 fullerene, homogenized and subjected to the differential centrifugation to retrieve mitochondrial fraction. The C60 fullerene content was quantified by HPLC-ESI-MS in extracts of cellular fractions. This data article refers to the research article “C60 Fullerene Accumulation in Human Leukemic Cells and Perspectives of LED-mediated Photodynamic Therapy” by Grebinyk et al. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10368 SN - 2352-3409 VL - 19 SP - 2047 EP - 2052 ER - TY - JOUR A1 - Bruun, Kristina A1 - Hille, Carsten T1 - Study on intracellular delivery of liposome encapsulated quantum dots using advanced fluorescence microscopy JF - Scientific Reports N2 - Quantum dots increasingly gain popularity for in vivo applications. However, their delivery and accumulation into cells can be challenging and there is still lack of detailed information. Thereby, the application of advanced fluorescence techniques can expand the portfolio of useful parameters for a more comprehensive evaluation. Here, we encapsulated hydrophilic quantum dots into liposomes for studying cellular uptake of these so-called lipodots into living cells. First, we investigated photophysical properties of free quantum dots and lipodots observing changes in the fluorescence decay time and translational diffusion behaviour. In comparison to empty liposomes, lipodots exhibited an altered zeta potential, whereas their hydrodynamic size did not change. Fluorescence lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS), both combined with two-photon excitation (2P), were used to investigate the interaction behaviour of lipodots with an insect epithelial tissue. In contrast to the application of free quantum dots, their successful delivery into the cytosol of salivary gland duct cells could be observed when applying lipodots. Lipodots with different lipid compositions and surface charges did not result in considerable differences in the intracellular labelling pattern, luminescence decay time and diffusion behaviour. However, quantum dot degradation after intracellular accumulation could be assumed from reduced luminescence decay times and blue-shifted luminescence signals. In addition to single diffusing quantum dots, possible intracellular clustering of quantum dots could be assumed from increased diffusion times. Thus, by using a simple and manageable liposome carrier system, 2P-FLIM and 2P-FCS recording protocols could be tested, which are promising for investigating the fate of quantum dots during cellular interaction. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12476 SN - 2045-2322 VL - 9 SP - 10504 ER - TY - JOUR A1 - Gerhard, Christoph A1 - Stappenbeck, Marco T1 - Impact of the Polishing Suspension Concentration on Laser Damage of Classically Manufactured and Plasma Post-Processed Zinc Crown Glass Surfaces JF - Applied Sciences N2 - The laser-induced damage threshold of optics is an issue of essential importance in high-power laser applications. However, the complex and partially interacting mechanisms as well as the underlying reasons for laser damage of glass surfaces are not yet fully understood. The aim of the present work is to contribute to a better understanding of such damage mechanisms by providing original results on the impact of classical glass surface machining on the laser-induced damage threshold. For this purpose, glass samples were prepared with well-defined process conditions in terms of the used lapping and polishing agents and suspensions. Further, the samples were post-processed by atmospheric pressure plasma for precision cleaning. The laser-induced damage threshold and surface contamination by residues from the manufacturing process were determined before and after plasma post-processing. It is shown that the polishing suspension concentration has a certain impact on the laser-induced damage threshold and surface contamination by residues from used working materials. The highest damage threshold of 15.2 J/cm² is found for the lowest surface contamination by carbon which occurs in the case of the highest polishing suspension concentration. After plasma treatment for merely 60 s, this value was increased to 20.3 J/cm² due to the removal of surface-adherent carbon. The results thus imply that the laser-induced damage threshold can notably be increased by first choosing appropriate process parameters during classical manufacturing and second plasma post-processing for surface finishing. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10556 SN - 2076-3417 VL - 8 IS - 9 SP - 1 EP - 15 PB - MDPI ER - TY - JOUR A1 - Steglich, Patrick A1 - Hülsemann, Marcel A1 - Dietzel, Birgit A1 - Mai, Andreas T1 - Optical Biosensors Based on Silicon-On-Insulator Ring Resonators: A Review JF - Molecules N2 - Recent developments in optical biosensors based on integrated photonic devices are reviewed with a special emphasis on silicon-on-insulator ring resonators. The review is mainly devoted to the following aspects: (1) Principles of sensing mechanism, (2) sensor design, (3) biofunctionalization procedures for specific molecule detection and (4) system integration and measurement set-ups. The inherent challenges of implementing photonics-based biosensors to meet specific requirements of applications in medicine, food analysis, and environmental monitoring are discussed. KW - biosensor KW - biophotonics KW - integrated optical sensor KW - aptamer KW - biomaterial KW - optical sensor KW - silicon photonics KW - ring resonator KW - lab-on-a-chip Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10822 SN - 1420-3049 VL - 24 IS - 3 ER - TY - JOUR A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Dietzel, Birgit A1 - Mai, Christian A1 - Schrader, Sigurd A1 - Casalboni, Mauro A1 - Mai, Andreas T1 - On-Chip Dispersion Measurement of the Quadratic Electro-Optic Effect in Nonlinear Optical Polymers Using a Photonic Integrated Circuit Technology JF - IEEE Photonics Journal N2 - A novel method to determine the dispersion of the quadratic electro-optic effect in nonlinear optical materials by using a silicon-on-insulator microring resonator is presented. The microring consists of a silicon slot waveguide enabling large dc electric field strength at low applied voltages. The dispersion of third-order hyperpolarizability of a linear conjugated dye is approximated by using a two-level model for the off-resonant spectral region. As an example, the dispersion of the resonance wavelength of the resonator filled with a dye doped polymer was measured in dependence of the applied dc voltage. The polymer was poly (methylmethacrylate) doped with 5 wt% disperse red 1 (DR1), and the measurements have been carried out at the telecommunication wavelength band around 1550 nm (optical C-band). The described measurements represent a new technique to determine the dispersion of the third-order susceptibility and molecular hyperpolarizability of the material filled into the slot of the ring-resonator. KW - electro-optical device KW - nonlinear optics KW - integrated optics KW - integrated optics material KW - optical material KW - integrated optics device KW - polymer active device Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12307 SN - 1943-0655 VL - 11 IS - 3 ER - TY - JOUR A1 - Lux, Helge A1 - Edling, Matthias A1 - Lucci, Massimiliano A1 - Kitzmann, Julia A1 - Villringer, Claus A1 - Siemroth, Peter A1 - De Matteis, Fabio A1 - Schrader, Sigurd T1 - The Role of Substrate Temperature and Magnetic Filtering for DLC by Cathodic Arc Evaporation JF - Coatings N2 - Diamond-like carbon (DLC) films were deposited using two different types of high current arc evaporation. The first process used a magnetic particle filter to remove droplets from the plasma. For the second process, the samples were put into a metallic cage which was placed directly above the plasma source. For both processes, we varied the substrate temperature from 21 to 350 °C in order to investigate the temperature effect. The samples were characterized using SEM, AFM, XPS, Raman Spectroscopy, Ellipsometry, Photometry, and Nano Indentation in order to compare both methods of deposition and provide a careful characterization of such DLC films. We found that the sp3 content and the hardness can be precisely adjusted by changing the substrate temperature. Furthermore, in the case of unfiltered deposition, the optical constants can be shifted in the direction of higher absorbance in order to produce black and hard carbon coatings. KW - DLC KW - ta-C KW - arc evaporation KW - substrate temperature KW - hardness KW - optical constant KW - ellipsometry Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12295 SN - 2079-6412 VL - 9 IS - 5 SP - 345 ER - TY - JOUR A1 - Grebinyk, Anna A1 - Prylutska, Svitlana A1 - Buchelnikov, Anatoliy A1 - Tverdokhleb, Nina A1 - Grebinyk, Sergii A1 - Evstigneev, Maxim A1 - Matyshevska, Olga A1 - Cherepanov, Vsevolod A1 - Prylutskyy, Yuriy A1 - Yashchuk, Valeriy A1 - Naumovets, Anton A1 - Ritter, Uwe A1 - Dandekar, Thomas A1 - Frohme, Marcus T1 - C60 Fullerene as an Effective Nanoplatform of Alkaloid Berberine Delivery into Leukemic Cells JF - Pharmaceutics N2 - A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle—C60 fullerene (C60)—for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C60-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV–Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C60 molecule. The computer simulation showed that π-stacking dominates in Ber and C60 binding in an aqueous solution. Complexation with C60 was found to promote Ber intracellular uptake. By increasing C60 concentration, the C60-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C60-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C60 improved its in vitro efficiency against cancer cells. KW - C60 fullerene KW - berberine KW - noncovalent nanocomplex KW - UV–Vis KW - DLS and AFM measurements KW - drug release KW - leukemic cell KW - uptake KW - cytotoxicity KW - apoptosis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12932 SN - 1999-4923 VL - 11 IS - 11 PB - MDPI ER - TY - JOUR A1 - Grebinyk, Anna A1 - Prylutska, Svitlana A1 - Chepurna, Oksana A1 - Grebinyk, Sergii A1 - Prylutskyy, Yuriy A1 - Ritter, Uwe A1 - Ohulchanskyy, Tymish Y. A1 - Matyshevska, Olga A1 - Dandekar, Thomas A1 - Frohme, Marcus T1 - Synergy of Chemo- and Photodynamic Therapies with C60 Fullerene-Doxorubicin Nanocomplex JF - Nanomaterials N2 - A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C60 fullerene (C60) were applied in 1:1 and 2:1 molar ratio, exploiting C60 both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox’s nuclear and C60’s extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox’s antiproliferative activity and C60’s photoinduced pro-oxidant activity. When cells were treated with 2:1 C60-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C60-Dox enabled a nanomolar concentration of Dox and C60 to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC50 16, 9 and 7 × 103-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C60’s photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C60-mediated Dox delivery and C60 photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C60-Dox nanoformulation provides a promising synergetic approach for cancer treatment. KW - photodynamic chemotherapy KW - synergistic effect KW - C60 fullerene KW - doxorubicin KW - nanocomplex KW - leukemic cell KW - apoptosis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12940 SN - 2079-4991 VL - 9 IS - 11 PB - MDPI ER -