Fluorescence polyelectrolytes

Ambade AV, Sandanara BS, Klaikherd A, Thayumanavan S (2007) Fluorescent polyelectrolytes as protein sensors. Polym Int 56 474-481... 

Whitten D, Jones R, Bergstedt T, McBranch D, Chen L, Heeger P (2001) From superquenching to biodetection building sensors based on fluorescent polyelectrolytes. In Ramamurthy V, Schanze KS (eds) Optical sensors and switches. Marcel Dekker Inc, New York... 

From Superquenching to Biodetection Building Sensors Based on Fluorescent Polyelectrolytes... 

II. SUPERQUENCHING OF FLUORESCENT POLYELECTROLYTES BY SMALL MOLECULE QUENCHERS... 

E. Formation of Films and Assemblies from Fluorescent Polyelectrolytes... 

The complexity observed in polymer fluorescence decay kinetics is further exacerbated when fluorescent polyelectrolytes are dissolved in aqueous media [29,30,33,35,37,43,120,122,128-132] segregation of the macromolecular structure into hydrophobic and hydrophilic-rich domains results in differing degrees of water penetration which further complicates the time-resolved fluorescence [26]. Within this context, more recent attempts to describe time-resolved polymer photophysical data include use of the blob model [133,134], which accounts for the range of environments encountered in heterogeneous systems by invoking a distribution of rate constants for excimer formation. 

Approximately a minimum of 1 to 5,000 is required before complexation is no longer dependent on molecular weight for small anions such as KI and l-ariiLinonaphthaLine-8-sulfonate (ANS) (86,87). The latter anion is a fluorescent probe that, when bound in hydrophobic environments, will display increased fluorescence and, as expected, shows this effect in the presence of aqueous PVP. PVP, when complexed with Hl, shrinks in si2e as it loses hydrodynamic volume, possibly because of interchain complexation. ANS, on the other hand, causes the polymer to swell by charge repulsion because it behaves like a typical polyelectrolyte (88). 

Pu KY, Liu B (2010) Fluorescence reporting based on FRET between conjugated polyelectrolyte and organic dye for biosensor applications. In Demchenko AP (ed) Advanced fluorescence reporters in chemistry and biology. II. Springer Ser Fluoresc 8 417 -53... 

In a more simple and cheap way, silver clusters can be prepared in aqueous solutions of commercially available polyelectrolytes, such as poly(methacrylic acid) (PM A A) by photo activation using visible light [20] or UV light [29]. Ras et al. found that photoactivation with visible light results in fluorescent silver cluster solutions without any noticeable silver nanoparticle impurities, as seen in electron microscopy and from the absence of plasmon absorption bands near 400 nm (F = 5-6%). It was seen that using PMAA in its acidic form, different ratios Ag+ MAA (0.15 1-3 1) lead to different emission bands, as discussed in the next section (Fig. 12) [20]. When solutions of PMAA in its sodium form and silver salt were reduced with UV light (365 nm, 8 W), silver nanoclusters were obtained with emission band centered at 620 nm and [Pg.322]

Achyuthan KE, Bergstedt TS, Chen L, Jones RM, Kumaraswamy S, Kushon SA, Ley KD, Lu L, McBranch D, Mukundan H, Rininsland F, Sh X, Xia W, Whitten DG (2005) Fluorescence superquenching of conjugated polyelectrolytes applications for biosensing and drug discovery. J Mater Chem 15 2648-2656... 

Pinto MR, Schanze KS (2004) Amplified fluorescence sensing of protease activity with conjugated polyelectrolytes. Proc Natl Acad Sci 101 7505-7519... 

Fluorescence Reporting Based on FRET Between Conjugated Polyelectrolyte and Organic Dye for Biosensor Applications... 

Keywords Conjugated polyelectrolyte DNA Energy transfer Fluorescence Protein Sensor... 

Woo F1Y, Vak D, Korystov D, Mikhailovsky A, Bazan GC, Kim DY (2007) Cationic conjugated polyelectrolytes with molecular spacers for efficient fluorescence energy transfer to dye-labeled DNA. Adv Funct Mater 17 290-295... 

Liu B, Bazan GC (2007) Tetrahydrofuran activates fluorescence resonant energy transfer from a cationic conjugated polyelectrolyte to fluorescein-labeled DNA in aqueous media. Chem Asian J 2 499-504... 

Wang Y, Liu B (2009) Conjugated polyelectrolyte sensitized fluorescent detection of thrombin in blood serum using aptamer-immobilized silica nanoparticles as the platform. Langmuir 25 12787-12793... 

L. M. Christian and W. R. Seitz, An optical ionic-strength sensor based on polyelectrolyte association and fluorescence energy transfer, Talanta 35, 119-122 (1988)... 

A detailed study of the structure of the aggregates of the ionic surfactants in polyelectrolyte networks was presented in Refs. [66,68]. The dynamics of the changes in the microenvironment of the fluorescent probe, pyrene, in slightly crosslinked networks of poly(diallyldimethylammonium bromide) (PDADMAB) during diffusion of sodium dodecyl sulfate (SDS) in the gel phase has been investigated by means of fluorescence spectroscopy. In Ref. [66], an analogous investigation was reported for complexes formal by the sodium salt of PMAA with cetyltrimethylammonium bromide (CTAB). 

The fluorescence intensity and lifetime of the Tb(III)-polyelectrolyte complex have been measured41 the polyelectrolytes used were poly(acrylic acid), copolymers of maleic acid with ethylene (MA-E), with isobutene (MA-fBu), and 2,4,4-trimethylpent-1-ene (MA-3MPe). The fluorescence intensity decreases in the order MA-3MPe > MA-iBu > MA-E > PAA and the lifetime is in the reverse order. 

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