Fluctuation spectroscopy

On the other hand, pDNA/PEI polyplexes were found to be not stable enough in the extracellular in vivo environment. Unpackaging of PEI and PEG-PEI polyplexes was observed [64, 65, 81], for example by serum proteins, soluble glycosaminoglycans, or extracellular matrix components. The situation is even worse in the case of siRNA polyplexes, where PEI polyplexes are dissociated in full human serum, as monitored by fluorescence fluctuation spectroscopy [66, 67]. 

Merkel OM, Librizzi D, Pfestroff A, Schurrat T, Buyens K, Sanders NN, De Smedt SC, Behe M, Kissel T (2009) Stability of siRNA polyplexes from poly(ethylenimine) and poly (ethylenimine)-g-poly(ethylene glycol) under in vivo conditions effects on pharmacokinetics and biodistribution measured by Fluorescence Fluctuation Spectroscopy and Single Photon Emission Computed Tomography (SPECT) imaging. J Control Release 138 148-159... 

Chen Y., Muller J. D., Eid J. S. and Gratton E. (2001) Two-Photon Fluorescence Fluctuation Spectroscopy, in Valeur B. and Brochon J. C. (Eds) New Trends in Fluorescence Spectroscopy. Applications to Chemical and Life Sciences, Springer-Verlag, Berlin, pp. 276-96. 

Dynamic processes at thermodynamic equilibrium that occur within a time range from sub-microseconds to seconds can be probed without the imposition of a transient disturbance by optical intensity fluctuation spectroscopy. As such, dynamic light scattering (DLS) [155] measures the fluctuation of quasielastic scattering intensity and fluorescence correlation spectroscopy (FCS) [156-158] measures concentration fluctuations of specific fluorescent molecules... 

G. Zumofen, J. Hohlbein, and C. G. Hiibner, Recurrence and photon statistics in fluorescence fluctuation spectroscopy. Phys. Rev. Lett. 93 260601 (2004). 

Blom, H., Kastrup, L., and Eggeling, C. (2006). Fluorescence fluctuation spectroscopy in reduced detection volumes. Curr. Pharm. Biotechnol. 7 51-66. 

Chen Y, Muller JD, So PTC, Gratton E. The photon counting histogram in fluorescence fluctuation spectroscopy. Biophys. J. 

Fig. 4.13. Chemical relaxation with a T-jump experiment and by fluctuation spectroscopy (FCS) with the reaction diffusion term...

L. Kastrup et al.. Fluorescence fluctuation spectroscopy in subdiffraction focal volumes. Phys. Rev. Lett. 94, 178104 (2005)... 

Quasi-elastic laser light scattering (also called intensity fluctuation spectroscopy, light-beating spectroscopy or photon correlation spectroscopy) is an accurate method to measure the translational diffusion coefficients of macromolecules. The diffusion coefficient is a parameter, that depends on the size and shape of the macromolecules and on the thermodynamic and hydrodynamic interaction between the macromolecules. 

Sakata H, Horiuchi M, Takahashi I, Kinjo M (2010) Conformational analysis of soluble oligomers of GFP tagged prion protein by fluorescence fluctuation spectroscopy. Curr Pharm Biotechnol 11 87-95... 

An excellent review of the early history of noise studies of different ionic systems, such as single pores in thin dielectric films, microelectrodes, and synthetic membranes, is reference 3. The review by Weissman (48) describes several state-of-the-art fluctuation spectroscopy methods that include (1) determination of chemical kinetics from conductivity fluctuations in salt solutions, (2) observation of conductivity noise that arises from enthalpy fluctuations in the electrolyte with high temperature coefficient of resistivity, and (3) detection of large conductivity fluctuations in a binary mixture near its critical point. 

More recently we have found that fluctuations in the scattered light intensity around its mean value give information about dynamics of the ripple motions in the film (intensity fluctuation spectroscopy). The rest of this chapter treats the light-scattering method in more detail. 

Because of relaxation of surface elevations, the scattered light has a broadened spectral distribution compared with the incident light. The broadening is too small to be analyzed by the conventional Fabry-Perot interferometry," however, so the more recent technique of light beating" must be used. We call this technique intensity fluctuation spectroscopy (IFS). 

Intensity fluctuation spectroscopy was used in our laboratory to study the dynamic behavior of surface ripples on thin liquid films. Both squeezing and bending modes were examined. To our knowledge one other group of researchers has obtained dynamic light-scattering data from thin soap films but as far as we know, nothing has been published in the official literature. Also some experiments were reported on lipid bilayers in water. ... 

This chapter can be regarded as optional since (a) it is not necessary for the logical development of the subject and (b) no light-scattering experiment has yet been performed which unambiguously gives rate constants. The reader s attention is directed to Section (6.6) for a discussion of Fluorescence Fluctuation Spectroscopy which has been successfully used to determine rate constants. 

In this chapter we present the theory of concentration fluctuations in chemically reacting systems. Only the simplest cases are considered in detail. The results of this chapter find application not only in light scattering, but also in fluorescence fluctuation spectroscopy (see Section 6.6). 

Polarization Fluctuation Spectroscopy obtaining particle shape... 

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