TY - JOUR A1 - Safinia, L. A1 - Dantan, Nathalie A1 - Höhse, Marek A1 - Mantalaris, A. A1 - Bismarck, A. T1 - Towards a methodology for the effective surface modification of porous polymer scaffolds JF - Biomaterials N2 - A novel low-pressure radio-frequency plasma treatment protocol was developed to achieve the effective through-thickness surface modification of large porous poly (d,l-lactide) (PDLLA) polymer scaffolds using air or water: ammonia plasma treatments. Polymer films were modified as controls. Scanning electron micrographs and maximum bubble point measurements demonstrated that the PDLLA foams have the high porosity, void fraction and interconnected pores required for use as tissue engineering scaffolds. The polymer surface of the virgin polymer does contain acidic functional groups but is hydrophobic. Following exposure to air or water: ammonia plasma, an increased number of polar functional groups and improved wetting behaviour, i.e. hydrophilicity, of wet surfaces was detected. The number of polar surface functional groups increased (hence the decrease in water contact angles) with increasing exposure time to plasma. The change in surface composition and wettablility of wet polymer constructs was characterised by zeta potential and contact angle measurements. The hydrophobic recovery of the treated PDLLA polymer surfaces was also studied. Storage of the treated polymer constructs in ambient air caused an appreciable hydrophobic recovery, whereas in water only partial hydrophobic recovery occurred. However, in both cases the initial surface characteristics decay as function of time. KW - Scaffold KW - Polyactic acid KW - Plasma KW - Surface modification KW - Contact angle KW - Wettability hydrophilicity PY - 2005 DO - https://doi.org/10.1016/j.biomaterials.2005.05.078 SN - 0142-9612 VL - 26 IS - 36 SP - 7537 EP - 7547 PB - Elsevier CY - Oxford AN - OPUS4-11487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scherz, Franziska A1 - Krop, U. A1 - Monks, K. A1 - Weller, Michael G. T1 - Antikörperreinigung mit Glasmonolithen - Vereinfachung von Affinitätstrennungen mit HPLC-Systemen JF - GIT Labor-Fachzeitschrift N2 - Druckstabile Glasmonolithen ermöglichen eine schnelle und unkomplizierte Reinigung von Antikörpern, z.B. aus Serum oder Zellkulturüberständen. Die sehr gute Regenerierbarkeit lässt eine lange Lebensdauer der Säulen erwarten, was die Kosten pro Probe niedrig hält. KW - Borosilicatglas KW - Immunglobuline KW - IgG KW - Serum KW - Plasma KW - Protein A KW - Protein G KW - Affinitätschromatographie KW - Agarose KW - Carrier-Material KW - Stationäre Phase KW - Immobilisierung KW - Highspeed KW - Trennung KW - Reinigung KW - Downstream Processing PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-445330 UR - http://www.git-labor.de/forschung/materialien/antikoerperreinigung-mit-glasmonolithen SN - 0016-3538 VL - 62 IS - 3 SP - 24 EP - 25 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-44533 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shabanov, Sergej V. A1 - Gornushkin, Igor B. T1 - Anions in laser-induced plasmas N2 - The equation of state for plasmas containing negative atomic and molecular ions (anions) is modeled. The model is based on the assumption that all ionization processes and chemical reactions are at local thermal equilibrium and the Coulomb interaction in the plasma is described by the Debye–Hu¨ckel theory. In particular, the equation of state is obtained for plasmas containing the elements Ca, Cl, C, Si, N, and Ar. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules CaCl2, CaCl, Cl2, N2, C2, Si2 , CN, SiN, SiC, and their positive and negative ions. The model is applied to laserinduced plasmas (LIPs) by including the equation of state into a fluid dynamic numerical model based on the Navier–Stokes equations describing an expansion of LIP plumes into an ambient gas as a reactive viscous flow with radiative losses. In particular, the formation of anions Cl-, C-, Si-, Cl2, Si2, C2 , CN-, SiC-, and SiN- in LIPs is investigated in detail. KW - Plasma modeling KW - Plasma KW - LIBS PY - 2016 DO - https://doi.org/10.1007/s00339-016-0175-8 VL - 2016 SP - Article Number: 676 PB - Applied Physics A, Springer AN - OPUS4-38771 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shelley, J.T. A1 - Stindt, Arne A1 - Riedel, Jens A1 - Engelhard, C. T1 - Time-resolved mass-spectral characterization of ion formation from a low-frequency, low-temperature plasma probe ambient ionization source JF - Journal of analytical atomic spectrometry N2 - New-found interest in the development of ionization sources for mass spectrometry, inspired by the advent of ambient desorption/ionization mass spectrometry, has led to a resurgence in plasma-source development and characterization. Dielectric-barrier discharges, particularly the low-temperature plasma (LTP) probe format, have been at the forefront of this field due to their low power consumption and relatively simple design. However, better fundamental understanding of this desorption/ionization source is needed to improve the analytical capabilities of such a device. Here, we use relatively fast (2.5 ms per spectrum) time-resolved mass spectrometry to characterize the temporal reagent-ion distribution from a low-frequency LTP probe. Different voltage waveforms were found to heavily influence the discharge properties and, consequently, ion production. Ion signals from short discharge pulses, ca. 40 µs, were found to be significantly broadened, ca. 10 ms, prior to extraction into the mass spectrometer. Additionally, higher frequencies of a sine-wave LTP produced the largest flux of reagent ions, which existed for most of the voltage waveforms. Finally, temporal signals for reagent and analyte ions were measured and related to specific ionization processes: proton transfer and charge transfer. KW - Time resolved KW - Mass spectrometry KW - Time of flight KW - Dielectric barrier discharge KW - Plasma KW - Atmospheric-pressure KW - Emission-spectrometry KW - Surface treatment PY - 2014 DO - https://doi.org/10.1039/c3ja50318f SN - 0267-9477 SN - 1364-5544 VL - 29 IS - 2 SP - 359 EP - 366 PB - Royal Society of Chemistry CY - London AN - OPUS4-30404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kühn, Gerhard A1 - Decker, Renate A1 - Roessner, D. A1 - Friedrich, Jörg Florian T1 - Influence of Plasma Treatment on the Molar Mass of Poly(ethylene terephthalate) Investigated by Different Chromatographic and Spectroscopic Methods JF - Journal of polymer science A, polymer chemistry N2 - The influence of different types of low and atmospheric pressure plasma on poly(ethylene terephthalate) (PET) has been studied in terms of changes in molar mass and molar mass distribution. Apart from a variation of plasma gases (oxygen, helium) different types of plasma (microwave, radio frequency, corona discharge) were used for the plasma surface modification. The changes in molar mass and types of functional end groups of lower molar mass products were investigated by means of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOFMS), whereas the high-molar mass fraction was analyzed by means of size-exclusion chromatography (SEC). The formation of crosslinked products during exposure to a helium plasma, which emits preponderately energy-rich and intense ultraviolet radiation, was proved by means of thermal field-flow fractionation (ThFFF). This method combined with a multiangle laser light scattering (MALLS) detector allows detection of weakly crosslinked polymers and microgels. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1639-1648, 1998 KW - Poly(ethylene terephthalate) KW - PET KW - Plasma PY - 1998 UR - http://www3.interscience.wiley.com/cgi-bin/abstract/36482/ABSTRACT DO - https://doi.org/10.1002/(SICI)1099-0518(19980730)36:10<1639::AID-POLA17>3.0.CO;2-H SN - 0360-6376 SN - 0887-624X VL - 36 IS - 10 SP - 1639 EP - 1648 PB - Wiley CY - Hoboken, NJ AN - OPUS4-6989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Yi A1 - Bierstedt, Andreas A1 - Riedel, Jens T1 - Spatial, temporal, and spectral characterization and kinetic investigations of a high repetition-rate laser-induced micro-plasma in air JF - Journal of Analytical Atomic Spectrometry N2 - Advances in laser-induced plasmas have enabled various rapid and simple analytical applications. Especially, their uses in the analyses of condensed-phase samples have drawn significant attention in the past few decades. Depending on the laser energy per pulse, various analytical goals can be achieved. Laser-induced airborne plasmas allow direct analysis of species in ambient air. Importantly, all of these applications are based on a fundamental understanding of the laser–medium interaction. Recent developments of diode-pumped solid-state lasers offer an alternative to conventional powerful, yet bulky lasers, which can specifically operate at high Repetition rates. Although these lasers deliver much lower power per pulse (mJ compared to mJ), the outstanding repetition rates offer significant improvement to meet statistical needs in some cases. In the present work, a mJ-laserinduced airborne plasma was characterized through optical emission analysis. By using a ns-timegated image detector coupled with specific bandpass filters, spatially, temporally, and spectrally resolved plasma images were recorded. Compared to conventional mJ-laser-induced plasmas, the one induced by mJ-lasers demonstrated unique features during its evolution. Specifically, measurements of the distribution of ionic and atomic species revealed distinctive energy/matter transfer processes during early ignition of the plasma. Meanwhile, dynamic investigations suggested subsequent matter transport in the later stage. KW - Laser-induced plasma KW - Plasma KW - DPSS-laser PY - 2019 UR - https://pubs.rsc.org/en/content/articlehtml/2019/ja/c9ja00163h DO - https://doi.org/10.1039/C9JA00163H SN - 0267-9477 VL - 34 IS - 8 SP - 1618 EP - 1629 PB - Royal Society of Chemistry CY - London AN - OPUS4-48622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -