TY - JOUR A1 - Dietrich, Paul A1 - Hennig, Andreas A1 - Holzweber, Markus A1 - Thiele, T. A1 - Borcherding, H. A1 - Lippitz, Andreas A1 - Schedler, U. A1 - Resch-Genger, Ute A1 - Unger, Wolfgang T1 - Surface analytical study of poly(acrylic acid)-grafted microparticles (beads): characterization, chemical derivatization, and quantification of surface carboxyl groups N2 - We report a surface analytical study of poly(methyl methacrylate) (PMMA) microparticles (beads) with a grafted shell of poly(acrylic acid) (PAA) with thicknesses up to 4 nm using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy. These polymer microparticles were analyzed before and after reaction of the surface carboxyl (CO2H) groups with 2,2,2-trifluoroethylamine (TFEA) to gain a better understanding of methods with use of covalently bound probe molecules for surface group analysis. The results obtained with chemical derivatization XPS using TFEA are discussed in terms of surface quantification of reactive CO2H groups on these PAA-coated microparticles. A labeling yield of about 50% was found for TFEA-derivatized particles with amounts of surface-grafted CO2H groups of 99 µmol/g or more, which is consistent with predicted reaction yields for homogeneously dispersed PAA hydrogels. KW - Polymer microparticles KW - Poly(acrylic acid)-grafted microparticles KW - Beads KW - XPS KW - SEM KW - NEXAFS KW - Surface analysis KW - Fluorine labeling PY - 2014 U6 - https://doi.org/10.1021/jp505519g SN - 1932-7447 SN - 1089-5639 VL - 118 IS - 35 SP - 20393 EP - 20404 PB - Soc. CY - Washington, DC AN - OPUS4-31326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heise, C. A1 - Schedler, U. A1 - Wettmarshausen, Sascha A1 - Friedrich, Jörg Florian T1 - Plasma-brominated cyclo-olefin polymer slides: Suiitable macroinitiators for activator regenerated by electron transfer/atom radical transfer polymerization N2 - Activators regenerated by electron transfer–atom radical transfer polymerization (ATRP) as a controlled living polymerization are distinguished by their acceptance of small amounts of transition-metal complexes and oxygen and by their tolerance of reducing agents at a high concentration. The precondition of all ATRP applications is the use of homolytic or heterolytic cleavable halides as a dormant species; this allows the propagation of monomer chains. Hence, alkyl bromides are slightly cleavable and are the preferred initiators for ATRP. The bromination of polymer slides used as macroinitiators was carried out under gentle bromoform plasma conditions. This led to an oxidation-resistant stable bromine layer. More than 20 bromines per 100 carbons on the polymer scaffold were permanently bound to the substrate after plasma treatment. The resulting amounts of secondary and tertiary bromines on the polymer scaffold exhibited a suitable macroinitiator concentration for the surface-initiated polymerization of methyl methacrylate and glycidyl methacrylate. KW - Copolymers KW - Functionalization of polymers KW - Grafting KW - Monolayers and polymer brushes KW - Radical polymerization PY - 2014 UR - http://onlinelibrary.wiley.com/doi/10.1002/app.40662/full U6 - https://doi.org/10.1002/APP.40662 SN - 0021-8995 SN - 1097-4628 VL - 131 IS - 16 SP - 40662-1 EP - 40662-10 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-30577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rödiger, S. A1 - Liebsch, C. A1 - Schmidt, C. A1 - Lehmann, W. A1 - Resch-Genger, Ute A1 - Schedler, U. A1 - Schierack, P. T1 - Nucleic acid detection based on the use of microbeads: a review N2 - Microbead-based technologies represent elegant and versatile approaches for highly parallelized quantitative multiparameter assays. They also form the basis of various techniques for detection and quantification of nucleic acids and proteins. Nucleic acid-based methods include hybridization assays, solid-phase PCR, sequencing, and trapping assays. Microbead assays have been improved in the past decades and are now important tools in routine and point-of-care diagnostics as well as in life science. Its advances include low costs, low workload, high speed and high-throughput automation. The potential of microbead-based assays therefore is apparent, and commercial applications can be found in the detection and discrimination of single nucleotide polymorphism, of pathogens, and in trapping assays. This review provides an overview on microbead-based platforms for biosensing with a main focus on nucleic acid detection (including amplification strategies and on selected probe systems using fluorescent labeling). Specific sections cover chemical properties of microbeads, the coupling of targets onto solid surfaces, microbead probe systems (mainly oligonucleotide probes), microbead detection schemes (with subsections on suspension arrays, microfluidic devices, and immobilized microbeads), quantification of nucleic acids, PCR in solution and the detection of amplicons, and methods for solid-phase amplification. We discuss selected trends such as microbead-coupled amplification, heterogeneous and homogenous DNA hybridization assays, real-time assays, melting curve analysis, and digital microbead assays. We finally discuss the relevance and trends of the methods in terms of high-level multiplexed analysis and their potential in diagnosis and personalized medicine. Contains 211 references. KW - Microbead KW - Microbead array KW - PCR KW - Microfluidic KW - Real-time KW - Multiplex PY - 2014 U6 - https://doi.org/10.1007/s00604-014-1243-4 SN - 0026-3672 SN - 1436-5073 VL - 181 IS - 11-12 SP - 1151 EP - 1168 PB - Springer CY - Wien AN - OPUS4-31183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -