Smoothly shifting fluorescent windows: a tunable “off-on-off” micellar sensor for pH

Pallavicini, Piersandro; Fernandez, Yuri Diaz; Pasotti, Luca

doi:10.1039/b913195g

Cited by 21 publications

(20 citation statements)

References 29 publications

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“…These authors investigated the acid‐base properties of different monobasic or dibasic compounds in the presence of neutral Triton‐X 100 surfactant medium (Figure ). The authors also designed a series of systems 44 – 50 with an “off‐on‐off” fluorescent pH window by assembling lipophilized pyridine and tertiary amine moieties with pyrene in the micellar milieu 56. The pyrene emission was found to be quenched by protonated pyridines and free tertiary amines in the ensemble, which might be due to the fact that protonated forms of pyridines or free tertiary amines are good electron acceptors or donors (respectively) from/to the excited state of dye molecules (PET quenchers).…”

Section: Identifying the Ph‐window And Lipophilicitymentioning

confidence: 99%

A Glimpse of Our Journey into the Design of Optical Probes in Self‐assembled Surfactant Aggregates

Dey

Bhattacharya

2016

The Chemical Record

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Dynamic self-assembling amphiphilic surfactant molecules, popularly known as "micelles", have received widespread attention, due to their ability to modulate the photophysical properties of various organic dyes upon encapsulation. Along with their well-known use as cleaning agents, catalysts in organic reactions, and even for drug delivery purposes, these surfactant assemblies also show promising pertinence in the recognition of both ionic and nonionic targeted analytes. Low micropolarity and relatively hydrophobic environments promote their interaction with ionic analytes, whereas neutral species mostly affect the aggregation pattern of the probe molecules upon partitioning inside the micellar hydrophobic milieu. The environment-sensitive nature of micelle-based self-assembled probes also prompts us to devise new sensor arrays for the recognition of multiple analytes. While this account will largely focus on our own work in developing surfactant-triggered self-assembled sensors, our findings have been placed in the context of the relevant contributions from others during their strategic evolution.

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Section: Identifying the Ph‐window And Lipophilicitymentioning

confidence: 99%

A Glimpse of Our Journey into the Design of Optical Probes in Self‐assembled Surfactant Aggregates

Dey

Bhattacharya

2016

The Chemical Record

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“…to the "on" portion of the fluorescence windows. We had already demonstrated that using the same fluorophore and the same bases, in TritonX-100 micelles, it was possible to shift the "on" window position on the right side of the pH axis by comicellization of increasing quantities of the anionic SDS surfactant (Pallavicini et al, 2009b). In the case of PHEA-PEG 5000 -C 16 micelles we added either SDS or the cationic CTAB (see Scheme 3), in order to shift the "on" position in both directions of the pH axis.…”

Section: Sensing Ph Windows With Fluorescencementioning

confidence: 98%

“…3:1 CTAB/PHEA-PEG5000-C16 molar ratio: grey squares. The solid lines are obtained by fitting I f % vs pH points with a two-sigmoid curve (Pallavicini et al, 2009b) and are added for graphical clarity. The I f % points bear ± 0.2 uncertainty.…”

Section: Sensing Ph Windows With Fluorescencementioning

confidence: 99%

“…On the other hand, if the surfactant would be kept over cmc it would be sufficiently concentrated to seriously damage living organisms. In the perspective of preparing new and biocompatible micellar fluorescent sensors for pH windows, we decided to step to polymeric micelles, that may act more advantageously as the containers for self-assembling the molecular components (Torchilin, 2007). Polymeric micelles are colloidal systems based on amphiphilic copolymers, which are able to self-assemble to micelle-like aggregates in aqueous media.…”

Section: Introductionmentioning

confidence: 99%

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Multicomponent polymeric micelles based on polyaspartamide as tunable fluorescent pH-window biosensors

Fernandez¹,

Mottini²,

Pasotti³

et al. 2010

Biosensors and Bioelectronics

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“…Supramolecular systems with photo 1-9 , redox, 10-21 and pH switchable [22][23][24][25] properties, in particular, devices with switchable binding and switchable color and lumi nescence, are widely studied. In the earlier created pH switching devices, switching occurs by the addition of acid and base.…”

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confidence: 99%

Reversible electrochemical pH-switching of luminescence in a p- sulfonatothiacalix[4]arene— terbium(3+) system

et al. 2010

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A quinone-hydroquinone system was used as a reversible electrochemical pH switcher of luminescence in the p sulfonatothiacalix[4]arene-terbium(3+) complex in an aqueous medium.Supramolecular systems with photo 1-9 , redox, 10-21 and pH switchable 22-25 properties, in particular, devices with switchable binding and switchable color and lumi nescence, are widely studied. In the earlier created pH switching devices, switching occurs by the addition of acid and base. This results in an increase in the salt con tent with each cycle. Therefore, switching occurs only restrictedly and, hence, this variant of pH switching can not be used for the creation of practically useful devices. In this connection, it is important to develop another method of pH switching when the reversible change in pH would be accompanied by the reversible change in the composition of the solution and functioning of such a system during unrestricted quantity of cycles.It is known 26 that the oxidation of organic compounds is often associated with proton elimination, whereas the reduction is accompanied by the accumulation of protons. At the same time, there are organic redox pairs in which redox processes involving protons are chemically reversible, for instance, pairs quinone-hydroquinone or nitroso compound-hydroxylamine. Therefore, reversible electrochemical switching of the pH of the medium with the reversible change in the composition of the solution during electrolysis is principally possible. The only prob lem is the choice of the pH of the switcher with a set of properties required for each particular case.Water soluble p sulfonatothiacalixarenes bind effi ciently bulky complex cations at the upper sulfonate rim, whereas metal ions are bound at the lower phenolate rim. 2,3 Complexes of this type are used in the creation of devices with redox and pH switching luminescence. 2,3 Now we report the results of investigation of the quinone-hydro quinone redox system as an electrochemical pH switcher of luminescence in the complex of p sulfonatothiacalix [4]arene (TCAS) with the Tb 3+ ion.The Tb 3+ ion itself does not luminesce, and its com plex with TCAS, in which the metal ion is bound at the lower phenolate rim, possesses high luminescence. Bind ing and, therefore, luminescence, are pH dependent. At pH 7 the Tb 3+ ion is bound and the complex luminesces, whereas at pH 3 the metal ion is bound to a lesser extent and the luminescence is quenched. 3,27 Taking into account these data, we stated a problem of electrochemi cal pH switching from 7 to 3 and back in a non buffer aqueous solution containing 0.1 М NaClO 4 as a support ing electrolyte and a system 5•10 -4 М TCAS + 5•10 -4 М Tb 3+ using the quinone-hydroquinone redox pair.The cyclic voltammograms (CV) of quinone reduc tion and hydroquinone oxidation at pH 3.04 and 7.01 in the absence and in the presence of TCAS were prelimi narily detected to determine the region of oxidation and reduction potentials. As it was expected, one peak of

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Smoothly shifting fluorescent windows: a tunable “off-on-off” micellar sensor for pH

Cited by 21 publications

References 29 publications

A Glimpse of Our Journey into the Design of Optical Probes in Self‐assembled Surfactant Aggregates

A Glimpse of Our Journey into the Design of Optical Probes in Self‐assembled Surfactant Aggregates

Multicomponent polymeric micelles based on polyaspartamide as tunable fluorescent pH-window biosensors

Reversible electrochemical pH-switching of luminescence in a p- sulfonatothiacalix[4]arene— terbium(3+) system

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