Search results for "fluorescence"
showing 10 items of 2463 documents
Studies of the binding of diolepoxide metabolites of polycyclic aromatic hydrocarbons to DNA using electrofluorescence polarization spectroscopy
1996
In the electrofluorescence method, a solution of DNA with covalently bound polycyclic hydrocarbons is placed in an electric field, and changes in the intensity of polarized fluorescence are observed. Under the correct conditions, these charges can be used to determine a value for the angle psi between the long axis of the hydrocarbon molecule and the axis of the DNA helix. For DNA or poly(dA-dT) treated with each stereoisomer of anti-benzo[c]phenanthrene diolepoxide, psi ranged from 55 degrees to 61 degrees, consistent with a mixture of quasi-intercalated adenine adducts and externally bound guanine adducts. Similar results were obtained with another set of 'fjord-region' diolepoxides, deri…
PHOSPHORORGANISCHE VERBINDUNGEN 1081DIE SYNTHESE FLUORESZIERENDER UND CHEMOSELEKTIVER REAGENTIEN ZUM GEZIELTEN NACHWEIS UND SCHUTZ BIOLOGISCH WICHTIG…
1984
Abstract Compounds of type A are fluorescent, if the donator groups, like NMe2, OMe, SMe and PR2, and the acceptor groups, like R′P(O)X, SO2R′ and CO2R′, are linked to different nuclei of the naphthalin ring system.
Synthesis of new, UV-photoactive dansyl derivatives for flow cytometric studies on bile acid uptake.
2009
Four new fluorescent derivatives of cholic acid have been synthesized; they incorporate a dansyl moiety at 3 alpha-, 3 beta-, 7 alpha- or 7 beta- positions. These cholic acid analogs are UV photoactive and also exhibit green fluorescence. In addition, they have been demonstrated to be suitable for studying the kinetics of bile acid transport by flow cytometry.
Pyrene derived functionalized low molecular weight organic gelators and gels
2008
Pyrene derived binary functionalized low molecular weight organic gelators (FLMOGs) and gels thereof in selected organic solvents were synthesized and characterized. The functionality refers to a functional group that does not take part in formation of the supramolecular gel network, but remains free and available for other purposes, such as to bind nanoparticles or other molecules into the gel structure. Functional groups were observed to disturb gel formation strongly, if they interact with each other within the same supramolecule due to the formation of competitive structures. Preventing such interactions restored the original gel properties. A gel with weaker supramolecular bonding than…
Flow Cytometry versus Fluorescence Microscopy
1996
Since the pioneer work of the botanist Matthias Jakob Schleiden and the zoologist Theodor Schwann in 1839, and of Rudolph Virchow in 1859, cell research progressed in two opposite directions. Cell biologists focused their increasingly more powerful microscopies into the cell structure to reveal the great morphological complexity of the cytoplasm. A growing number of subcellular organelles thus challenged the early biochemists to discover their specific molecular features and their coordination to maintain an ordered cell life. The biochemists’ answer to such a challenge consisted usually in tearing apart cells into their discrete components and obtaining information on molecules and pathway…
Development of Polyamine‐Substituted Triphenylamine Ligands with High Affinity and Selectivity for G‐Quadruplex DNA
2019
Currently, significant efforts are devoted to designing small molecules able to bind selectively to guanine quadruplexes (G4s). These noncanonical DNA structures are implicated in various important biological processes and have been identified as potential targets for drug development. Previously, a series of triphenylamine (TPA)-based compounds, including macrocyclic polyamines, that displayed high affinity towards G4 DNA were reported. Following this initial work, herein a series of second-generation compounds, in which the central TPA has been functionalised with flexible and adaptive linear polyamines, are presented with the aim of maximising the selectivity towards G4 DNA. The acid-bas…
Putting molecules in their place.
2014
Each class of microscope is limited to imaging specific aspects of cell structure and/or molecular organization. However, imaging the specimen by complementary microscopes and correlating the data can overcome this limitation. Whilst not a new approach, the field of correlative imaging is currently benefitting from the emergence of new microscope techniques. Here we describe the correlation of cryogenic fluorescence tomography (CFT) with soft X‐ray tomography (SXT). This amalgamation of techniques integrates 3D molecular localization data (CFT) with a high‐resolution, 3D cell reconstruction of the cell (SXT). Cells are imaged in both modalities in a near‐native, cryopreserved state. Here we…
Spectroscopic study of the loading of cationic porphyrins by carbon nanohorns as high capacity carriers of photoactive molecules to cells
2019
Carbon nanomaterials are attractive candidates for drug delivery due to their high surface area, ease of functionalisation and biocompatibility. This work describes the spectroscopic monitoring of the loading capacity of oxidised carbon nanohorns for two cationic porphyrins. Addition of the COOH functionalised carbon nanohorns to both meso-tetra(4-N-methylpyridyl) free base (H2TMPyP4) and platinum (PtTMPyP4) porphyrin in aqueous solution results in hypochromism of the Soret band and quenching of the porphyrin emission. These changes are used to monitor the non-covalent binding interactions with the nanohorn surface and determine the surface loading. The colloidal stability of the nanohorns …
Polylactic is a Sustainable, Low Absorption, Low Autofluorescence Alternative to Other Plastics for Microfluidic and Organ-on-Chip Applications
2020
Organ-on-chip (OOC) devices are miniaturized devices replacing animal models in drug discovery and toxicology studies. The majority of OOC devices are made from polydimethylsiloxane (PDMS), an elastomer widely used in microfluidic prototyping, but posing a number of challenges to experimentalists, including leaching of uncured oligomers and uncontrolled absorption of small compounds. Here we assess the suitability of polylactic acid (PLA) as a replacement material to PDMS for microfluidic cell culture and OOC applications. We changed the wettability of PLA substrates and demonstrated the functionalization method to be stable over a time period of at least 9 months. We successfully cultured …
Modifying the body distribution of HPMA-based copolymers by molecular weight and aggregate formation.
2011
There is a recognized need to create well-defined polymer probes for in vivo and clinical positron emission tomography (PET) imaging to guide the development of new generation polymer therapeutics. Using the RAFT polymerization technique in combination with the reactive ester approach, here we have synthesized well-defined and narrowly distributed N-(2-hydroxypropyl)methacrylamide homopolymers (pHPMA) (P1* and P2*) and random HPMA copolymers consisting of hydrophilic HPMA and hydrophobic lauryl methacrylate comonomers (P3* and P4*). The polymers had molecular weights below (P1* and P3*) and above the renal threshold (P2* and P4*). Whereas the homopolymers dissolve in isotonic solution as in…