Fluorescence ratiometric pH sensor prepared from covalently immobilized porphyrin and benzothioxanthene

Abstract

A fluorescence ratiometric sensor for pH determination is described in this paper. The sensor incorporated the pH-sensitive dye meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP) as an indicator and a pH-insensitive dye N-(2-methacryloxyethyl)benzo[k,l]thioxanthene-3,4-dicarboximide (MBTD), a benzothioxanthene derivative, as a reference for fluorescence ratiometric measurement. To prevent leakage of the dyes, both were photocopolymerized with acrylamide, hydroxyethyl methacrylate, and triethylene glycol dimethacrylate on the silanized glass surface. The reproducibility and response time of the prepared sensor were sufficient. Most common coexisting inorganic ions and organic compounds did not interfere with pH sensing. In the acidic pH range from 1.5 to 5.0 the fluorescence intensity ratio of the two dyes varied linearly as a function of pH. The sensing membrane was found to have a lifetime of at least one month. The sensor was applied to the analysis of waste water and artificial samples.

Bactenecin 7 peptide fragment as a tool for intracellular delivery of a phosphorescent oxygen sensor

“…DNA synthesis), which was observed for the fragment [5,8]. The short (15)(16)(17)(18)(19)(20)(21)(22)(23)(24) fragment contains five prolines of 10 residues and, when carrying a small (fluorescein isothiocyanate, FITC) or even large (60-kDa NeutrAvidin) cargo, is able to penetrate mammalian cells with an efficiency comparable with that of the TAT peptide [5].…”

“…In this article, we describe a novel phosphorescent oxygen-sensitive probe for intracellular use which comprises a bactenecin 7 peptide fragment (15)(16)(17)(18)(19)(20)(21)(22)(23)(24) conjugated with the uncharged monofunctional derivative of Pt(II) coproporphyrin I (PEPP0). This probe provides efficient loading of various mammalian cells, including PC12, HCT116, SH-SY5Y and HeLa, via cell-type-dependent uptake mechanisms.…”

“…The intracellular delivery of porphyrins conjugated with cell-penetrating peptides is of particular interest in photodynamic cancer therapy (photosensitizers), for imaging agents and for intracellular probes for oxygen and other parameters [9][10][11][12][13][14][15][16]. The targeted delivery of porphyrins and, in particular, their metal complexes in subcellular compartments has been hindered by their significant size and hydrophobicity [17][18][19].…”

“…In this article, we report the synthesis of a cell-penetrating phosphorescent oxygen sensor based on the uncharged PtCP moiety and the bactenecin 7 peptide fragment (15)(16)(17)(18)(19)(20)(21)(22)(23)(24). This probe, termed PEPP0, demonstrates an ease of synthesis, improved intracellular distribution and is more efficient than other previously described PtCP conjugates for the noninvasive, realtime, phosphorescence lifetime-based sensing of intracellular oxygen in cultures of adherent mammalian cells.…”

A Highly Selective Fluorescent Sensor for Cu2+ Based on a Covalently Immobilized Naphthalimide Derivative

“…To date, several optical chemical sensors have been reported in which indicator dyes were covalently attached onto the activated surface of glass slides by UV irradiation. [24][25][26][27][28][29] In this work, we have developed a fluorescent sensor for Cu 2+ based on covalently immobilized derivative of naphthalimide via a photo-polymerization method.…”