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- 2019 (2) (entfernen)
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- Englisch (2) (entfernen)
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- Fluorescence (2)
- BODIPYs (1)
- Cobaloxime complex (1)
- Fluorophores (1)
- Gas sensing (1)
- Molecularly Imprinted Polymers (1)
- Sulfide sensing (1)
Organisationseinheit der BAM
A “turn-on” fluorescence sensing system based on a BODIPY-cobaloxime complex for the detection of H2S in liquid and gas phase was developed. To that aim, two cobaloxime complexes bearing an axial pyridyl-BODIPY ligand were initially evaluated as sensitive fluorescent HS− indicators in aqueous solution. The sensing mechanism involves the selective substitution of the BODIPY ligand by the HS− anion at the cobalt center, which is accompanied by a strong fluorescence enhancement. The selection of a complex with an ideal stability and reactivity profile toward HS− relied on the optimal interaction between the cobalt metal-center and two different pyridyl BODIPY ligands. Loading the best performing BODIPY-cobaloxime complex onto a polymeric hydrogel membrane allowed us to study the selectivity of the probe for HS− against different anions and cysteine. Successful detection of H2S by the fluorescent “light-up” membrane was not only accomplished for surface water but could also be demonstrated for relevant H2S concentrations in gas phase.
The development of new strategies for the sensing of phosphorylated and carboxylate-containing biomolecules such as phosphorylated tyrosine and histidine or sialic acid is currently of strong interest because those molecules are often involved in cancerous processes. Molecularly Imprinted Polymers (MIPs) are formed through the polymerization of a set of functional monomers and cross-linkers in the presence of a target molecule or an analogue of it. The target molecule is incorporated into the polymer network due to non-covalent interactions established with one or more functional monomers. Because those interactions are weak, the target molecule can be desorbed a posteriori from the polymer matrix, leaving imprinted cavities of complementary size, shape and electronic nature. Resembling the antigen-binding site of an antibody, MIPs can then be highly selective towards the target molecule. Besides these features, our approach involves also the use of functional fluorescent monomers which undergo fluorescence changes upon binding of the target molecule. This allows us to investigate the sensing process using fluorescence as a highly sensitive read-out. To that aim we present here the use of silica particles which contain a MIP shell formed by thiourea or guanidinium functionalized dyes for the recognition of phosphorylated and carboxylate-containing molecules of biological relevance in polar, protic solvents.