Conjugated Polymers as a New Class of Dual-Mode Matrices for MALDI Mass Spectrometry and Imaging.

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and MALDI MS imaging are ubiquitous analytical methods in medical, pharmaceutical, biological, and environmental research. Currently, there is a strong interest in the investigation of low molecular weight compounds (LMWCs), especially to trace and understand metabolic pathways, requiring the development of new matrix systems that have favorable optical properties and a high ionization efficiency and that are MALDI silent in the LMWC area. In this paper, five conjugated polymers, poly{[ N, N'-bis(2-octyldodecyl)-naphtalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5,5'(2,2'-bithiophene)} (PNDI(T2)), poly(3-dodecylthiophene-2,5-diyl) (P3DDT), poly{[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl]- alt-(thiophene-2,5-diyl)} (PTQ1), poly{[ N, N'-bis(2-octyldodecyl)-isoindigo-5,5'-diyl] -alt-5,5'(2,2'-bithiophene)} (PII(T2)), and poly(9,9-di- n-octylfluorenyl-2,7-diyl) (P9OFl) are investigated as matrices.

Reconstitution properties of biologically active polymersomes after cryogenic freezing and a freeze-drying process.

Reconstitution of biologically active polymersomes from the frozen or solid state into any fluid state is still a challenging issue for the design of new biological experiments and for the formulation of therapeutic agents. To gain knowledge about the reconstitution of pH-responsive and photo-crosslinked polymersomes, surface-functionalized and enzyme-containing polymersomers were cryogenically frozen (-20 °C) or freeze-dried with inulin as the lyoprotectant (0.1% w/v) and stored for a defined time period.

Interactions of Nitroxide-Conjugated and Non-Conjugated Glycodendrimers with Normal and Cancer Cells and Biocompatibility Studies.

Poly(propyleneimine) glycodendrimers fully modified with maltose units were administered to different cancer cell lines and their effect on cell viability was evaluated by using MTS assay and flow cytometry. The mechanism of dendrimer-cell interactions was investigated by the electron paramagnetic resonance (EPR) technique by using a new nitroxide-conjugated glycodendrimer. The nitroxide groups did not modify both the biological properties (cell viability and apoptosis degree) of the dendrimers in the presence of the cells and the dendrimer-cell interactions.

Palladium-catalyzed chain-growth polycondensation of AB-type monomers: high catalyst turnover and polymerization rates.

Chain-growth catalyst-transfer polycondensations of AB-type monomers is a new and rapidly developing tool for the preparation of well-defined π-conjugated (semiconducting) polymers for various optoelectronic applications. Herein, we report the Pd/PtBu3-catalyzed Negishi chain-growth polycondensation of AB-type monomers, which proceeds with unprecedented TONs of above 100,000 and TOFs of up to 280 s(-1). In contrast, related AA/BB-type step-growth polycondensation proceeds with two orders of magnitude lower TONs and TOFs.

Formation of oligomeric and macrocyclic ureas based on 2,6-diaminopyridine.

The conversion of 1,3-bis-(6-amino-pyridin-2-yl)-urea (1) with N,N'-carbonyldiimidazole at high temperatures in DMSO yielded a mixture of defined cyclic trimers and tetramers. On the basis of model reactions, exchange reactions were evidenced, which convert the cyclic tetramer into a stable cyclic trimer. Linear even numbered oligomers were obtained in acetone under reflux where side reactions were suppressed.

Synthesis of Allyl-Terminated Polar Macromonomers by Metallocene-Catalyzed Polymerizations of 10-Undecene-1-ol.

Poly(10-undecene-1-ol) macromonomers were synthesized by metallocene-catalyzed polymerization using vinyl chloride as a chain transfer agent. Using this technique, predominantly allyl terminated polymers could be obtained, which was verified by NMR spectroscopy and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). By means of the mass spectra, a detailed interpretation of the nature of the head and end groups of these polymers was possible.

Water sorption properties of carbonized layers produced by controlled B+ bombardment of thin polyimide and polysulfone films.

Thin polyimide (PI) and polyethersulfone (PES) films are widely used as functional layers for microelectronic sensors. Ion implantation modifies the layer structure and morphology of these polymers and hence results in new mechanical and optical properties. However, ion-modified layers also show a change in sensitivity to moisture uptake under specific conditions.