CO2/pH-responsive particles with built-in fluorescence read-out

yesA novel fluorescent monomer was synthesized to probe the state of CO2-responsive cross-linked polymeric particles. The fluorescent emission of this aminobromomaleimide-bearing monomer, being sensitive to protic environments, can provide information on the core hydrophilicity of the particles and therefore indicates the swollen state and size of the particles. The particles’ core, synthesized from DEAEMA (N,N-diethylaminoethyl methacrylate), is responsive to CO2 through protonation of the tertiary amines of DEAEMA. The response is reversible and the fluorescence emission can be recovered by simply bubbling nitrogen into the particle solution. Alternate purges of CO2 and N2 into the particles’ solution allow several ON/OFF fluorescence emission cycles and simultaneous particle swelling/shrinking cycles.British Petroleum Company (BP), Engineering and Physical Sciences Research Council (EPSRC

Dual effect of thiol addition on fluorescent polymeric micelles: ON-to-OFF emissive switch and morphology transition

YesThe morphology transition from micelles to vesicles of a solution-state self-assembled block copolymer, containing a fluorescent dye at the core–shell interface, has been induced by an addition–elimination reaction using a thiol, and has been shown to be coupled to a simultaneous ON-to-OFF switch in particle fluorescence.EPSRC and the IAS at the University of Warwic

Fluorescent probes for stimuli-responsive polymers : to fluoresce, or not to fluoresce?

This thesis explores the use of aminobromomaleimide and dithiomaleimide functionalities to probe their environment. These fluorescent functionalities were incorporated into responsive polymeric nanostructures allowing their behaviour to be read-out upon external stimuli. Chapter 1 gives a brief introduction on nanoparticles formation and the polymerisation techniques used throughout the thesis. The properties of bromo- and thio-maleimides and their use in protein and polymer chemistry were also introduced. Chapter 2 describes a morphology transition simultaneously with a fluorescence on-to-off switch as a result of the modification of the dithiomaleimide substituent. Chapter 3 presents the synthesis of a library of aminomaleimides and explores their fluorescent properties. In Chapter 4, the fluorescent properties of aminobromomaleimide were incorporated into CO2-responsive polymeric nanoparticles for a built-in read-out of the CO2-response. Chapter 5 explores the possibility of using the fluorescent properties of aminobromomaleimide to read-out the behaviour of glutathione-responsive particle

Process poesis A comparison of the concept of God found in Whiteheadian process theology and in the narrative fiction of Nikos Kazantazakis

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN008526 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Supplementary information files for Aminomaleimide fluorophores: a simple functional group with bright, solvent dependent emission

Supplementary files for Aminomaleimide fluorophores: a simple functional group with bright, solvent dependent emission. Amino-substituted maleimides form a new class of highly emissive compounds, with large Stokes shifts (>100 nm) and high quantum yields (up to ∼60%). Emission is responsive to the maleimide's environment with both a red-shift, and quenching, observed in protic polar solvents. Aminomaleimides are easily functionalised, providing a versatile fluorescent probe.</div

New functional handle for use as a self-reporting contrast and delivery agent in nanomedicine

The synthesis and photophysical characterization of a chromophore-bridged block copolymer system is presented. This system is based on a dithiomaleimide (DTM) functional group as a highly emissive functionality which can readily be incorporated into polymeric scaffolds. A key advantage of this new reporter group is its versatile chemistry, ease of further functionalization, and notably small size, which allows for ready incorporation without affecting or disrupting the self-assembly process critical to the formation of core–shell polymeric contrast and drug delivery agents. We demonstrate the potential of this functionality with a diblock system which has been shown to be appropriate for micellization and, when in the micellar state, does not self-quench. The block copolymer is shown to be significantly more emissive than the lone dye, with a concentration-independent emission and anisotropy profile from 1.5 mM to 0.15 μM. An emission lifetime and anisotropy decay comparison of the block copolymer to its micelle displays that time-domain fluorescence lifetime imaging (FLIM) is able to rapidly resolve differences in the supramolecular state of this block–dye–block polymer system. Furthermore, the ability to resolve these differences in the supramolecular state means that the DTM micelles are capable of self-reporting when disassembly occurs, simply by monitoring with FLIM. We demonstrate the great potential for in vitro applications that this system provides by using FLIM to observe micelle disassembly in different vascular components of rat hippocampal tissue. In total this system represents a new class of in-chain emitter which is appropriate for application in quantitative imaging and the tracking of particle degradation/disassembly events in biological environments

Aminomaleimide fluorophores: a simple functional group with bright, solvent dependent emission

Amino-substituted maleimides form a new class of highly emissive compounds, with large Stokes shifts (>100 nm) and high quantum yields (up to ∼60%). Emission is responsive to the maleimide's environment with both a red-shift, and quenching, observed in protic polar solvents. Aminomaleimides are easily functionalised, providing a versatile fluorescent probe.</p

Conjugation-Induced Fluorescent Labeling of Proteins and Polymers Using Dithiomaleimides

Dithiomaleimides (DTMs) with alkyl substituents are shown to be a novel class of highly emissive fluorophores. Variable solubility and further functionalization can easily be tailored through the choice of N and S substituents. Inclusion of a DTM unit into a ROP/RAFT initiator or insertion into the disulfide bond of salmon calcitonin (sCT) demonstrates the utility for fluorescent labeling of polymers and proteins. Simultaneous PEGylation and fluorescent labeling of sCT is also demonstrated, using the DTM unit as both a linker and a fluorophore. It is anticipated that DTMs will offer an attractive alternative to commonly used bulky, planar fluorophores

New Functional Handle for Use as a Self-Reporting Contrast and Delivery Agent in Nanomedicine

The synthesis and photophysical characterization of a chromophore-bridged block copolymer system is presented. This system is based on a dithiomaleimide (DTM) functional group as a highly emissive functionality which can readily be incorporated into polymeric scaffolds. A key advantage of this new reporter group is its versatile chemistry, ease of further functionalization, and notably small size, which allows for ready incorporation without affecting or disrupting the self-assembly process critical to the formation of core–shell polymeric contrast and drug delivery agents. We demonstrate the potential of this functionality with a diblock system which has been shown to be appropriate for micellization and, when in the micellar state, does not self-quench. The block copolymer is shown to be significantly more emissive than the lone dye, with a concentration-independent emission and anisotropy profile from 1.5 mM to 0.15 μM. An emission lifetime and anisotropy decay comparison of the block copolymer to its micelle displays that time-domain fluorescence lifetime imaging (FLIM) is able to rapidly resolve differences in the supramolecular state of this block–dye–block polymer system. Furthermore, the ability to resolve these differences in the supramolecular state means that the DTM micelles are capable of self-reporting when disassembly occurs, simply by monitoring with FLIM. We demonstrate the great potential for in vitro applications that this system provides by using FLIM to observe micelle disassembly in different vascular components of rat hippocampal tissue. In total this system represents a new class of in-chain emitter which is appropriate for application in quantitative imaging and the tracking of particle degradation/disassembly events in biological environments