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An organic/inorganic hybrid membrane as a solid "turn-on" fluorescent chemosensor for coenzyme A (CoA), cysteine (Cys), and glutathione (GSH) in aqueous media.

Vallejos S, Estévez P, Ibeas S, García FC, Serna F, García JM - Sensors (Basel) (2012)

Bottom Line: In this way, the water insoluble sensing motif can be exploited in aqueous media.The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II).The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Burgos, Spain. svallejos@ubu.es

ABSTRACT
The preparation of a fluorogenic sensory material for the detection of biomolecules is described. Strategic functionalisation and copolymerisation of a water insoluble organic sensory molecule with hydrophilic comonomers yielded a crosslinked, water-swellable, easy-to-manipulate solid system for water "dip-in" fluorogenic coenzyme A, cysteine, and glutathione detection by means of host-guest interactions. The sensory material was a membrane with gel-like behaviour, which exhibits a change in fluorescence behaviour upon swelling with a water solution of the target molecules. The membrane follows a "turn-on" pattern, which permits the titration of the abovementioned biomolecules. In this way, the water insoluble sensing motif can be exploited in aqueous media. The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II). The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.

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Cross interaction CoA, Hg(II) and (3) in DMSO:H2O (80:20) solution (left), and interaction of the hybrid membrane M2 with CoA in water (pH = 7.4, TRIS) (right).
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f7-sensors-12-02969: Cross interaction CoA, Hg(II) and (3) in DMSO:H2O (80:20) solution (left), and interaction of the hybrid membrane M2 with CoA in water (pH = 7.4, TRIS) (right).

Mentions: Following the previously described procedure for the study of the interaction of 3 with Hg(II), the complex stoichiometry of (3):X (X = CoA, Cys and GSH) and the stability constants were determined following the fluorescence quenching of 3 in solution. The results are shown in Table 1 and have an equimolar complex stoichiometry in all cases. These results show that the biomolecules also interact with the sensory motif 3 within the membrane causing the fluorescence quenching; however, the interaction was significantly weaker than the interaction between Hg(II) and 3. The following complex behaviour of the sensory material M2 was observed upon adding the biomolecules to the measurement media: (a) an initial recovery of the fluorescence was observed until a maxima was reached, which corresponded to the displacement of the Hg(II) bound to the sensory motif in M2 due to the interaction of Hg(II) and the biomolecule; and (b) the quenching of the fluorescence upon increasing the concentration of the biomolecule passed the maxima due to the interaction between the sensory moieties of M2 and the biomolecule. This phenomenon was also observed studying the system in solution, as depicted in Figure 7. As pointed out it Section 3.1 and shown in Figure 4, a titration curve to measure CoA, Cys and GSH at nanomolar concentrations could be drawn. The upper concentration detection limit depended on the amount of the sensing monomer within the membrane bound to Hg(II), which could easily be modified by varying the monomer feed ratio in the membrane synthesis. The ratio of the monomer to Hg(II) was preferably 1:1, so the concentration window that the sensory material could measure was tunable. The interaction strengths between the three target molecules and the sensory motif were similar, as was estimated in solution by the stability constants (see Table 1), which permits a similar sensing behaviour of the hybrid film M2 in relation to the fluorescence “turn-on” pattern for detecting the biomolecules.


An organic/inorganic hybrid membrane as a solid "turn-on" fluorescent chemosensor for coenzyme A (CoA), cysteine (Cys), and glutathione (GSH) in aqueous media.

Vallejos S, Estévez P, Ibeas S, García FC, Serna F, García JM - Sensors (Basel) (2012)

Cross interaction CoA, Hg(II) and (3) in DMSO:H2O (80:20) solution (left), and interaction of the hybrid membrane M2 with CoA in water (pH = 7.4, TRIS) (right).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376624&req=5

f7-sensors-12-02969: Cross interaction CoA, Hg(II) and (3) in DMSO:H2O (80:20) solution (left), and interaction of the hybrid membrane M2 with CoA in water (pH = 7.4, TRIS) (right).
Mentions: Following the previously described procedure for the study of the interaction of 3 with Hg(II), the complex stoichiometry of (3):X (X = CoA, Cys and GSH) and the stability constants were determined following the fluorescence quenching of 3 in solution. The results are shown in Table 1 and have an equimolar complex stoichiometry in all cases. These results show that the biomolecules also interact with the sensory motif 3 within the membrane causing the fluorescence quenching; however, the interaction was significantly weaker than the interaction between Hg(II) and 3. The following complex behaviour of the sensory material M2 was observed upon adding the biomolecules to the measurement media: (a) an initial recovery of the fluorescence was observed until a maxima was reached, which corresponded to the displacement of the Hg(II) bound to the sensory motif in M2 due to the interaction of Hg(II) and the biomolecule; and (b) the quenching of the fluorescence upon increasing the concentration of the biomolecule passed the maxima due to the interaction between the sensory moieties of M2 and the biomolecule. This phenomenon was also observed studying the system in solution, as depicted in Figure 7. As pointed out it Section 3.1 and shown in Figure 4, a titration curve to measure CoA, Cys and GSH at nanomolar concentrations could be drawn. The upper concentration detection limit depended on the amount of the sensing monomer within the membrane bound to Hg(II), which could easily be modified by varying the monomer feed ratio in the membrane synthesis. The ratio of the monomer to Hg(II) was preferably 1:1, so the concentration window that the sensory material could measure was tunable. The interaction strengths between the three target molecules and the sensory motif were similar, as was estimated in solution by the stability constants (see Table 1), which permits a similar sensing behaviour of the hybrid film M2 in relation to the fluorescence “turn-on” pattern for detecting the biomolecules.

Bottom Line: In this way, the water insoluble sensing motif can be exploited in aqueous media.The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II).The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Burgos, Spain. svallejos@ubu.es

ABSTRACT
The preparation of a fluorogenic sensory material for the detection of biomolecules is described. Strategic functionalisation and copolymerisation of a water insoluble organic sensory molecule with hydrophilic comonomers yielded a crosslinked, water-swellable, easy-to-manipulate solid system for water "dip-in" fluorogenic coenzyme A, cysteine, and glutathione detection by means of host-guest interactions. The sensory material was a membrane with gel-like behaviour, which exhibits a change in fluorescence behaviour upon swelling with a water solution of the target molecules. The membrane follows a "turn-on" pattern, which permits the titration of the abovementioned biomolecules. In this way, the water insoluble sensing motif can be exploited in aqueous media. The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II). The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.

Show MeSH
Related in: MedlinePlus