A new platform has been developed for DNA lesion detection using a cationic conjugated polymer (CCP). DNA that contains two adjacent thymine bases is irradiated with ultraviolet light to allow for the formation of cyclobutane pyrimidine dimers and pyrimidine–pyrimidone dimers. The DNA lesions block the primer extension, and the base labeled with fluorescein cannot be incorporated into the DNA strand. Addition of the CCP leads to inefficient fluorescence resonance energy transfer (FRET) from CCP to fluorescein. For the case without DNA lesions, successful primer extension allows for efficient FRET between them. In view of the FRET signal changes, the DNA lesions can be detected. This new protocol offers a convenient detection for DNA lesions in aqueous solution without any isolation and washing steps.
Summary: An initiator for nitroxide mediated ‘living’ free radical polymerization was prepared with a fluorescent tag attached to the initiating alkyl radical terminus. This was used to synthesize amphiphilic poly(acrylic acid)‐block‐polystyrene diblock copolymers, which self assembled in a tetrahydrofuran/buffer solution to form structures that are visible by fluorescence.
A series of monodisperse six‐arm benzene‐cored star oligofluorenes are prepared by a divergent/convergent strategy, starting from the repetitive divergent synthesis of symmetrical ethynyl‐bridged oligofluorenes to the convergent Co‐catalyzed alkyne cyclotrimerization. The structures of these six‐arm molecules are fully characterized. The diameter of the largest molecule SF3 reaches ca. 3 nm. These highly substituted star‐shaped oligomers exhibit extremely high fluorescent quantum yields in solution and unexpected red‐shifted and broadened emission with fine structure in the film as a result of the formation of stable aggregates.
Microporous organic polymers offer the possibility of storing hydrogen safely at low temperatures and moderate pressures via physisorption. A range of polymers of intrinsic microporosity (PIMs) have been studied. The best PIM to date is based on a triptycene monomer and takes up 2.7% H2 by mass at 10 bar/77 K. Hypercrosslinked polymers (HCPs) also show promising performance, particularly at pressures >10 bar. The form of the H2 isotherm is influenced by the micropore distribution, a higher concentration of ultramicropores (pore size <0.7 nm), as found in PIMs, being associated with enhanced low pressure adsorption. The performance of polymers relative to other microporous materials (carbons and metal‐organic frameworks) is compared and promising methods to enhance the hydrogen uptake of microporous polymers are suggested.
Grafted conjugated polyelectrolytes were synthesized for the first time and characterized. The polymers demonstrated properties of a convenient and efficient protocol for creating Hg2+ sensors. The unique character of the new material comes from an anionic counterion nature with no external cofactors, and imparts high selectivity and fast detection for mercury ion in a fluorescence probe. The concept may be potentially applied to create new sensors for monitoring other ions.
Herein we describe a novel and simple conjugated polymer‐fluorescent probe based platform for trypsin detection from protein mixtures in homogeneous solution. This platform takes advantage of specific interaction between the probe and the active site of trypsin and the electrostatic interaction between the polymer and the protein to mediate energy transfer between the polymer and the probe. This method does not require any separation steps, which should facilitate high‐throughput protease screening and drug discovery.
Binary reactive/inert antifouling polymer brushes were grafted via a two step surface initiated polymerization from printed initiator monolayer and provided robust, effective polymeric surfaces for bioattachment with distinguishably reduced non‐specific adsorption. This synthetic strategy can be harnessed to build complex binary polymeric structures on substrate surfaces and the polymer brush surfaces reported in the present paper can be widely used for versatile biological study.
Organic polymers that contain ligated metals offer a variety of unique properties which include luminescence, electro‐ and photochemistry, catalysis, charge, magnetism, and thermochromism. These organic–inorganic hybrid materials have the potential to offer novel active matrixes for advanced devices. Continued progress in synthetic chemistry and molecular characterization will enable such advanced materials. Here the focus is restricted to side‐chain metal complexes with emissive properties that highlight the use of lanthanide ions as opposed to the often‐studied transition metal complexes.
A simple and direct method for derivatization of solid polysaccharides is presented. The novel methodology is based on the combination of organic acid‐catalyzed esterification or etherification and photochemical thiol‐ene click derivatization of a heterogeneous polysaccharide. The solid cellulose was “organoclick” modified with aryl, alkyl and polyester groups, respectively. The modification allows for a highly modular and metal free surface modification of solid polysaccharides.
Summary: We analyzed quantitatively the effects of temperature on the morphologic evolution of the desorption process in hot water measured ex situ by atomic force microscopy. The morphology of the hole that forms with immersion of the polyelectrolyte film in hot water has characteristics similar to those from polymer dewetting processes near the glass transition temperature. The hole diameter immediately reaches a maximum in the desorption process while the number of holes increases linearly with time.
AFM images of the morphology of PEM film after immersion in hot water 60 min. 相似文献
Fluorescent image patterns of a substituted acetylene polymer film with a large FFV were successfully obtained by a µCP method using several kinds of chemical ink compounds. PO and SCA generated positive‐type fluorescent image patterns. On the other hand, an ethanolic solution of DNT generated a negative‐type fluorescent image pattern due to a significant quenching effect. An NMP solution of NR gave a two‐color image pattern due to an intermolecular energy transfer from PTMSDPA to NR.
We report syntheses of phenylene‐, biphenylene‐, and terphenylene‐layered polymers with a xanthene scaffold by the modified Suzuki‐Miyaura coupling reaction. Their optical properties were studied in detail. The polymer end‐capped by nitrobenzene units, which act as fluorescence quenchers, exhibited the photo‐excited energy transfer from the layered oligophenylenes to the terminal units.
A water‐soluble, sulfur‐containing fluorescent conjugated polymer exhibits a visible fluorescence color change for detection of mercury in the presence of thymine. A new concept provides the design of a sensor ensemble using a simple combination method. This strategy avoids the need for complicated design and synthesis of a recognition group, eliminating the tedious synthetic efforts for the preparation of a sensor material.
POSS‐functionalized polyisobutylenes (PIBs) were synthesized by carbocationic polymerization using an epoxy‐POSS/TiCl4 initiating system in hexane/methyl chloride (60:40 v/v) solvent mixture at −80 °C. 1H NMR spectroscopy verified the incorporation of one epoxy‐POSS per polymer chain. Light scattering and TEM analysis demonstrated the formation of 50–100 nm sized aggregates and micron‐sized clusters.
Synthesis of a water‐soluble polydiacetylene has been achieved by topochemical polymerization in the solid state of the bis(N‐methylimidazolium)diacetylene monomer. Structural characterization for the monomer by X‐ray diffraction and NMR spectroscopy supports a photopolymerization initiated at the surface. Characterization of the polymer (NMR, UV and Raman spectroscopy, and dynamic light scattering) is given along with a molecular modelling interpretation of the polymerization in the solid state.
Chromophore‐containing dendritic structures (G1, G2) are utilized to intercalate layered silicates, which results in a large d‐spacing up to 126 Å. An exfoliated morphology is obtained by mixing the dendritic structure intercalated layered silicates with polyimide in N,N‐dimethylacetamide solution. The dendritic structures attached on the clay template would arrange in a non‐centrosymmetric manner. This self‐assembled arrangement brought about the electro‐optical coefficients of 5–6 pm · V−1 for these relatively low chromophore‐containing organic/inorganic nanocomposites without resorting to poling. Excellent temporal stability (100 °C) is also achieved.
We have created a new functional biosensor coating composed of polyelectrolyte multilayers containing gold nanoparticles. This gold‐hybridized polyelectrolyte multilayer film possesses a stable nanoporous structure under physiological conditions. Antibody molecules were successfully conjugated onto the gold nanoparticles within the film. This functional coating successfully extinguished false signals from non‐specific binding of proteins and cells and also provided highly enhanced detection sensitivity. Furthermore, the drastic differences in protein and cellular adhesion properties between a chip coated with the nanoporous PEM film and a bare chip demonstrate that morphological control of biological interactions on chip surfaces is possible.
The intrinsic photoluminescence properties of hyperbranched polyethylenimines (PEIs) and their linear counterpart (LPEIs) have been studied in absence of any classical fluorescent probes. The comparison of the inherent fluorescence emission between hyperbranched polyethylenimines and their linear analogues demonstrates that linear polyamines are capable of producing strong intrinsic photoluminescence species having long excited lifetimes without need of having a tridimensional‐branched structure. The creation of inherently fluorescent polymeric centers from hyperbranched and linear polyethyleimines can be modulated by specific chemical modification and oxidation of amine groups as well as by adjusting the acidity of the polymer.
The Michael reaction of chitosan with acrylic acid was carried out successfully, even in water alone as the reaction medium. As a consequence of its good solubility in water, the reaction product, N‐carboxyethylchitosan, showed excellent biodegradable properties with standard activated sludge.
We describe an enzyme‐responsive polymeric vehicle, which is of great interest in controlled drug delivery, biosensing, and other related areas. The polymer synthesized using lipase as catalyst in DMSO has a favorable molecular structure that is quickly hydrolyzed by lipase in aqueous phase, and allows a fast release of encapsulated molecules.
