Fluorescent PET (photoinduced electron transfer) sensors

Bissell, Richard A.; Silva, A. Prasanna de; Gunaratne, H. Q. Nimal; Lynch, P. L. Mark; Maguire, Glenn E. M.; McCoy, Colin; Sandanayake, K. R. A. Samankumara

doi:10.1007/3-540-56746-1_12

Cited by 391 publications

(97 citation statements)

References 171 publications

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“…Observed fluorescence time profiles were analyzed by iterative reconvolution with the measured instrument response functions using a nonlinear least-squares fitting procedure based on the Marquardt-Levenberg algorithm using a commercially available software package (Picoquant, FluoFit v3.1.0). Goodness of fit was assessed by minimizing the reduced chi squared function, 2 , and a visual inspection of the weighted residuals. Support plane error analysis was performed with a 2.5% confidence interval on the reduced 2 function.…”

Section: Methodsmentioning

confidence: 99%

Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential

et al. 2005

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The emission from two photoactive 14-membered macrocyclic ligands, 6-((naphthalen-1-ylmethyl)-amino) trans-6,13-dimethyl-13-amino-1,4,8,11-tetraaza-cyclotetradecane (L 1 ) and 6-((anthracen-9-ylmethyl)-amino)-trans-6, 13-dimethyl-13-amino-1,4,8,11-tetraaza-cyclotetradecane (L 2 ) is strongly quenched by a photoinduced electron transfer (PET) mechanism involving amine lone pairs as electron donors. Time-correlated single photon counting (TCSPC), multiplex transient grating (TG), and fluorescence upconversion (FU) measurements were performed to characterize this quenching mechanism. Upon complexation with the redox inactive metal ion, Zn(II), the emission of the ligands is dramatically altered, with a significant increase in the fluorescence quantum yields due to coordination-induced deactivation of the macrocyclic amine lone pair electron donors. For [ZnL 2 ] 2+ , the substituted exocyclic amine nitrogen, which is not coordinated to the metal ion, does not quench the fluorescence due to an inductive effect of the proximal divalent metal ion that raises the ionization potential. However, for [ZnL 1 ] 2+ , the naphthalene chromophore is a sufficiently strong excited-state oxidant for PET quenching to occur.

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Section: Methodsmentioning

confidence: 99%

Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential

et al. 2005

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“…In sensors such as 1-5, the fluorescent chromophore having a benzylic nitrogen is only weakly fluorescent due to photoinduced electron transfer, PET. 16 Upon complexation of the toxin, PET is turned off, and the chromophore fluoresces normally. The usual mechanism invoked for this type of PET quenching is complexation of a ligand to the benzylic nitrogen lone pair.…”

Section: Discussionmentioning

confidence: 99%

Effect of crown ether ring size on binding and fluorescence response to saxitoxin in anthracylmethyl monoazacrown ether chemosensors

Mao¹,

Thorne²,

Pharr³

et al. 2006

Can. J. Chem.

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Convenient macrocyclization synthetic routes for the preparation of different-sized monoaza anthracylmethyl crown ether chemsensors (15-crown-5, 18-crown-6, 21-crown-7, 24-crown-8 and 27-crown-9) are described. Evaluation of these crowns as chemosensors for saxitoxin revealed that the larger crowns have moderately higher binding constants, with the 27-crown-9 chemosensor having the largest binding constant: 2.29×10 5 M −1 . Fluorescence enhancements of 100% were observed at saxitoxin concentrations of 5 μM, which is close to the detection limit in mouse bioassay. KeywordsAnthracene; Crown ethers; Saxitoxin; PSP; binding constants; chemsensors Harmful algal blooms (HABs) are linked to many cases of human poisoning each year. Economic losses and costs to the fishing industry, public health, and tourism are estimated to be $40,000,000 annually, as of the late 1990s 1 . The toxins produced by HABs, as well as many other analytes of interest to members of the biomedical community are "small molecules". Saxitoxin (STX) (Figure 1) is such a small molecule because of its neurotoxicity, and is the most toxic component of the paralytic shellfish poisons (PSPs). 2 Its activity is manifested through the binding of the toxin to voltage-gated sodium channels and blocking sodium ion transport across neuronal membranes. In 1996, Saxitoxin was included on the United States government's list of "Select Agents" (potential terrorist weapons). It is one of only 3 small molecules on the list; the rest are viruses (e.g., ebola), bacteria (e.g., Yersenia pestis), and proteins (e.g., ricin, abrin). Mouse bioassay is the current method used by government agencies to detect saxitoxin and its derivatives (known collectively as paralytic shellfish poisons, or PSPs), 3 but for both ethical and economic reasons, an alternative would be highly beneficial. We have been working for several years to develop fluorescent chemosensors for the detection of saxitoxin, and have recently made significant advances. Specifically, we have shown that arylmethylcrowns are selective for the detection of saxitoxin over sodium, potassium, and calcium ions, 4 as well as several organic analytes, 5 including tetrodotoxin (Figure 1). 6 The latter point is clinically relevant since saxitoxin and ‡ This paper is dedicated to Alfred Bader, in recognition of his many contributions, both personal and professional, to the chemical enterprise. Until now we have focussed on the 18-crown-6 monoaza or diaza crown ethers, with anthracene, coumarin, or acridine fluorophores. In early work, Cram, showed that 27-crown-9 crown ether is the optimum size to host a guanidinium guest. 9,10 Since saxitoxin ( Figure 1) is a bis-guanidinium dication, we explored larger crown sizes to determine the effect on binding, using the anthracene fluorophore as sensor. Thus, crown ethers 1-5 were prepared and evaluated for fluorescence response to saxitoxin: 15-crown-5 (1, n=1), 18-crown-6 (2, n = 2), 21-crown-7 (3, n=3), 24-crown-8 (4, n=4) and 27-crown-9 (5, n=5) ( Figure 1). Synthes...

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“…As the electron transfer is distance dependent (a function of 1/r 6 ), for 1 and 2 the ethylene spacer gives rise to some deactivation of the excited state, even in alkaline solution, where it is in competition with PET. 20 However, it has recently been reported that the ethylene spacer shows greater biological resistance to degradation then a methylene spacer (which is commonly used), 7,8 which is important in the present context as these sensors are developed with the aim of continuous monitoring of pH in blood. In contrast to the above results, compound 5, which lacks the amino receptor, did not show any changes in emission properties as a function of pH except at very low pH where the 4-amino moiety was protonated.…”

Section: Ground and Excited State Investigation Of 1 And 2 In Solutionmentioning

confidence: 99%

Towards the development of controllable and reversible ‘on-off’ luminescence switching in soft-matter; synthesis and spectroscopic investigation of 1,8-naphthalimide-based PET (photoinduced electron transfer) chemosensors for pH in water-permeable hydrogels

Gunnlaugsson¹,

McCoy²,

Phelan³

et al. 2003

Arkivoc

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The synthesis of the pH PET sensors 1 and 2 is described. These molecules display 'on-off' switching in their fluorescence as a function of pH in aqueous solution. From the luminescent changes pK a values of 8.4(±0.1) and 6.3(±0.1) were determined respectively. These compounds were incorporated into poly[methylmethacrylate-co-2-(hydroxyethylmethacrylate)]-based hydrogels and the luminescent properties of the resulting polymeric films were investigated using confocal laser-scanning microscopy. Both sensors showed substantial luminescent switching in the soft-matter, where the emission was 'switched off' after treating the hydrogels with alkaline solution and 'switched on' under acidic conditions.

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Fluorescent PET (photoinduced electron transfer) sensors

Cited by 391 publications

References 171 publications

Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential

Tuning the Photophysical Behavior of Luminescent Cyclam Derivatives by Cation Binding and Excited State Redox Potential

Effect of crown ether ring size on binding and fluorescence response to saxitoxin in anthracylmethyl monoazacrown ether chemosensors

Towards the development of controllable and reversible ‘on-off’ luminescence switching in soft-matter; synthesis and spectroscopic investigation of 1,8-naphthalimide-based PET (photoinduced electron transfer) chemosensors for pH in water-permeable hydrogels

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