Label free phosphate functionalized semiconducting polymer dots for detection of iron(III) and cytochrome c with application to apoptosis imaging.

We report on facile synthesis and characterization of phosphate-functionalized polymer dots (PDs) by doping tributyl phosphate (TBP) in a semiconducting polymer poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1,4-benzo-{2,10-3}-thiadiazole)] (PFBT). Then, the prepared TBP@PFBT PDs were used to develop a very high sensitive probe for detection Fe3+, Cu2+ ions and Cytochrome c based on aggregation induced fluorescence off mechanism. The PDs exhibited a linear dynamic range for Fe3+ from 0.1 to 2 nM with a detection limit of 30 pM and for Cu2+ from 2.0 to 50.0 nM with a detection limit of 0.35 nM. Meanwhile, this probe showed a linear dynamic range for Cyt c from 175 to 1750 pM with a detection limit of 32.7 pM. The TBP@PFBT PDs is a simple, one-step, fast, non-invasive, label-free, and inexpensive probe that is capable of online apoptosis monitoring response to drugs with an ever-present opportunity to contribute in a variety of in-vitro and in-vivo biological applications. We also obtained sharp, specific 2D and 3D imaging results for early stage apoptosis in breast cancer cells. Moreover, this technique possesses the advantage of rapid determination of Fe3+ ion in biological or environmental samples. Importantly, this label-free assay provides short determination time of only a few min, easy operation and very low LOD allowing 100-4000 times increased in sensitivity over previously reported probes, together with high selectivity without need to using biorecognition elements like enzymes, antibodys and/or aptamers. Such excellent features make the TBP@PFBT PDs an excellent probe for successful apoptosis imaging in live cells.

A highly selective semiconducting polymer dots-based "off-on" fluorescent nanoprobe for iron, copper and histidine detection and imaging in living cells.

Semiconducting polymer dots (PDs) hold a great promise as fluorescence nanoprobes, due to their photostability, biocompatibility, and high quantum yield. Herein, the synthesis and characterization of highly fluorescent PDs for selective and sensitive detection of Fe3+,Cu2+, and histidine (His) have been reported. First, carboxyl functionalized poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-(2,1',3)-thiadiazole)] (PFBT) PDs were synthesized through a nano-precipitation technique, and then they were functionalized by -COOH groups using 9-anthracenecarboxylic acid. The formation of PDs was proved using transmission electron microscopy, dynamic light scattering, and Fourier transform infrared (FTIR) spectroscopy analyses. The PDs exhibited a yellow fluorescence with a peak centered at 540 nm (photo-excited at 460 nm) with a quantum yield of 25%. The fluorescence of PDs significantly quenched in the presence of Cu2+ ion, and then selectively recovered upon addition of His, providing the possibility of constructing a sensitive Cu2+-His off-on fluorescent nanoprobe. The PDs exhibited a linear dynamic range for Cu2+ from 0.1 to 630 µmol L-1 with a limit of detection of 61.7 nmol L-1, and for Fe3+ from 0.1 to 720 µmol L-1 with a limit of detection of 58.1 nmol L-1. In addition, the PDs/Cu2+ probe showed a linear dynamic range for His from 0.1 to 920 µmol L-1 with a limit of detection of 79.6 nmol L-1. Besides, the prepared PDs/Cu2+ probe exhibited a promising potential for selective and sensitive sensing of His in blood serum and for intracellular imaging.

Response surface optimized peroxyoxalate chemiluminescence of octahydro-Schiff base derivative as new luminophor and study of the quenching effect of some cations, amino acids and cholesterol.

We report the first detailed study of the characteristics of an octahydro-Schiff base derivative as a new luminophor in the peroxyoxalate chemiluminescence (POCL) system. The effect of reagents on this new POCL system was investigated. In addition, the response surface methodology was used for evaluating the relative significance of variables in this POCL system, establishing models and determining optimal conditions. The quenching effect of some cations and compounds such as Cu(2+), Fe(3+), Hg(2+), imidazole, histidine and cholesterol on an optimized POCL reaction were studied. The dynamic ranges were up to approximaterly 100 and 175 × 10(-6) M for Cu(2+) and cholesterol respectively. The detection limits were 3.3 × 10(-6) m and 2.58 × 10(-6) m for Cu(2+) and histidine, respectively. In all cases the relative standard deviations were 4-5% (n = 4).

A study of peroxyoxalate-chemiluminescence of 4,4'-bis{[4,6-bis (2-hydroxyethyl)amino-1,3,5-triazin-2-yl]amino}stilbene-2,2'-disulfonic acid-disodium salt as a novel blue fluorescer.

The chemiluminescence arising from the reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of brightener 4,4'-bis{[4,6-bis(2-hydroxyethyl)amino-1,3,5-triazin-2-yl]amino}stilbene-2,2'-disulfonic acid-disodium salt (Triazinyl) has been studied. The influence of concentration of TCPO, hydrogen peroxide, Triazinyl, base catalysts and temperature on the resulting chemiluminescence was investigated. The kinetic parameters for the peroxyoxalate-chemiluminescence (PO-CL) of Triazinyl were evaluated from computer fitting of the resulting intensity-time plots. The activation energies, E(a), were evaluated from temperature dependence of the corresponding rise and fall rate constants.

Novel sulfate ion-selective polymeric membrane electrode based on a derivative of pyrilium perchlorate.

A sulfate ion-selective PVC membrane sensor based on 4-(4-bromophenyl)-2,6-diphenylpyrilium perchlorate (BDPP) as a novel sensing material is successfully developed. The electrode shows a good selectivity for sulfate ion with respect to common organic and inorganic anions. The sensor exhibits a good linear response with slope of -28.9+/-0.5 mV per decade over the concentration range of 1.0x10(-6)-1.0x10(-2) M, and a detection limit of 8.0x10(-7) M of SO(4)(2-) ions. The electrode response is independent of pH in the range of 4.0-9.0. The proposed sensor was applied as an indicator electrode in potentiometric titration of sulfate and barium ions, and to the determination of zinc in zinc sulfate tablets.