Hydroxypyrene trisulfonic acid

The first intravascular sensor for simultaneous and continuous monitoring of the pH, pC>2, and pCC>2 was developed by CDI-3M Health Care (Tustin CA)14 based on a system designed and tested by Gehrich et al.15. Three optical fibres (core diameter = 125 pm) are encapsulated in a polymer enclosure, along with a thermocouple embedded for temperature monitoring (Figure 3). pH measurement is carried out by means of a fluorophore, hydroxypyrene trisulfonic acid (HTPS), covalently bonded to a matrix of cellulose, attached to the fibre tip. Both the acidic ( eXc=410 nm) and alkaline ( exc=460 nm) excitation bands of the fluorophore are used, since their emission bands are centred on the same wavelength (/-cm 520 nm). The ratio of the fluorescence intensity for the two excitations is measured, to render the sensor relatively insensitive to fluctuations of optical intensity. 

Membrane-covered optochemical sensors (optodes) with O2 sensitive or pH sensitive fluorescence indicators (e.g. pyrene butyric acid or hydroxypyrene trisulfonic acid) have been coupled with different enzyme reactions, such as the conversion of glucose, lactate, ethanol, or xanthine, and with antigen-antibody couples (Opitz and Lubbers, 1987). 

This procedure is based on the method of Smith, Opie, Waw-zonek, and Prichard3 for the preparation of 2,3,6-trimethyl-phenol. 3-Hydroxypyrene has been prepared by fusion of pyrene-3-sulfonic acid with sodium hydroxide 4 and by desul-fonation of 3-hydroxypyrene-5,8,10-trisulfonic acid with hot, dilute sulfuric acid.5... 

Fig. 1.5. Examples of hydrophobic, hydrophilic and amphiphilic probes. 1 pyrene. 2 8-hydroxypyrene-l,3,6-trisulfonic acid, trisodium salt (pyranine). 3 8-alkoxypyrene-l,3,6-trisulfonic acid, trisodium salt. 4 1-...

Pyranine, 8-hydroxypyrene-l,3,6-trisulfonic acid 8-Hydroxypyrene-1,3,6-trisulfonic acid (HPTS, also known as pyranine) can be used as a pH indicator. At low pH, HPTS fluorescence is greater with 405 nm excitation, whereas at neutral pH, fluorescence at 440 nm excitation is greater than at 405 nm excitation. Therefore, a strong fluorescence signal at 405 nm excitation indicates HPTS in acidic compartments (endosomes and lysosomes) a strong signal at 440 nm indicates HPTS in neutral compartments (cytosol) (126 128). 

Ertekin and coworkers developed an additional optical COj sensor based on the fluorescence signal intensity changes of the pH-sensitive fluorescent dye 8-hydroxypyrene-l,3,6-trisulfonic acid trisodium salt (HPTS) dissolved in ILs [18]. When HCO3 was added to HPTS solution, the fluorescence intensity of the peak centered around 520 nm decreased by 90% in [C4Qlm] [BF4] and by 75% in [C4Cilm]Br. The reported detection limit for CO2 (g) was 1.4% while the detection limit for dissolved COj was 10 M HCO3. The sensor exhibited excellent stability and repeatability over a time period >7 months. 

The samples used were 10"5 M aqueous solutions of 8-hydroxypyrene-I,3,6-trisulfonic acid trisodium salt (HPTS or 3sPyOH) (Sigma-Aldrich) in buffers of pH 6 and pH 10. UV-Vis absorption spectra of the dye solutions at different pH environments were obtained with a Hitachi U-4001 uv-vis spectrophotometer. 

Ruthenium complexes with mixed bipyridyl ligands, immobilized inside a Nation film, may also be used as pH-sensitive sensor layers [90]. A completely different approach for a ratiometric imaging of pH sensor foils was developed for diagenetic studies of marine sediments, using the dual fluorescence excitation ratio of the pH-sensitive fluorophore 8-hydroxypyrene-l,3,6-trisulfonic acid (HPTS) [91]. Commonly used dual fluorophors with different absorption and emission maxima in the protonated and basic form for ratiometric measurements are the naphthofluorescein and seminaphthofluorescein derivates (SNARF and SNAFL) [92], It should be noted that ammonia or carbon dioxide can also be detected by some of these pH-sensitive materials [55,93]. 

Figure 12 (line A) depicts the emission spectrum of hydroxy pyrene trisulfonate dissolved in diluted buffer (pH 5.0). At this pH, the ground state is fully protonated (pK0 = 7.7), but not so the first excited singlet state (pK = 0.5). The excited molecules dissociate and 95% of the emission is at the wavelength of the excited anion (515 nm). The dissociation can be prevented if the compound is dissolved in acid solution, pH < pK., such as 2MHC1 (line B). Under such conditions, we observe the emission of the neutral form with maximum at 445 nm. Upon ligation to apomyoglobin, the fluorescence of hydroxypyrene trisulfonate consists of two... 

Methylumbelliferone (4-MU) incorporated in polyacrylamide capsules permeable to protons was the earliest fluorophore investigated for intravascular fluorimetric measurements [45]. The emission spectrum displays an isosbestic wavelength at 330 nm, and the dissociated form has its peak at 365 nm. The ratio of the measured intensities is related to the pH. The response time is less than 2 minutes. This pH measurement (range 6.5-8.5) is advantageously taken with determination of the ionic strength [46] in combination with 1-hydroxypyrene-3,6,8-trisulfonic acid (HPTS) [47] (see Section 17.1.1.3). 

Figure 18 Comparison of the rate of HPTS [8-hydroxypyrene-1,3,6-trisulfonic acid (pyranine)] release from liposomes (eggPC) modified with NIPPAm-containing copolymers and the phase transition of the copolymer (NIPPAm/MAA/ODA 93 5 2 mol%). The copolymer phase transition was measured as Em increase in light scattering at 480 nm. HPTS release was measured as an increase in HPTS fluorescence following release from hposomes (Aex = 413nm, Aem = 512nm) and is expressed as a fraction of the fluorescence upon hposome soluhilization with Triton X-100. (Adapted from Ref. 117.)...

Near-neutral pH fluorescein diacetate, carboxyfluorescein and Its esters, 5-sulfofluorescein diacetate, BCECF Acidic pH di- and trifluorofluoresceins (Oregon Green) and dichlorofluores-cein, 9-amino-6-chloro-2-methoxyacri-dine, 8-hydroxypyrene-l,3,6-trisulfonic acid (HPTS)... 

Hydroxypyrene-1,3,6-trisulfonic acid, sodium salt. See Solvent green 7 8-Hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt. See Cl 59040 D C Green No. 8 Solvent green 7... 

Fig. 12 The distribution of the symplasmic tracer (HPTS -8-hydroxypyrene-l,3,6-trisulfonic acid) within the protodermal cells ol Arabidopsis explants. A - stomata as an example of the permanent symplasmic domain. B-C examples of the temp)oral symplasmic domains composed of a few cells (C) or in a single cell (D as to B, note the imequal distribution of fluorochromes in the daughter cells after a division - arrow bar = 10 pm).

Figure 5.22 Six carbohydrate receptors consisting of cationic bis-boronic acid appended benzyl viologens [3,3 -olm-, 4,3 -olm-, and 4,4 -o/m-BBV) and the anionic fluorescent dye 8-hydroxypyrene-l,3,6-trisulfonic acid trisodium salt (HPTS). Three corresponding benzyl viologens (3,3 -, 4,3 -, and 4,4 -BV) were used as controls.

Hydroxypyrene-1,3,6-trisulfonic acid trisodium sail (HPTS) (Pyranine)... 

HYDROXYPYRENE-l,3,6-TRISULFONIC ACID TRISODIUM SALT (HPTS) (PYRANINE)... 

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