Bioimaging

In this advancement, Mahmoud et al. investigated the effect of surface charge of fluorescent-labeled CNCs as chemically synthesized CNCs-fluorescein isothiocyanate (CNCs-FITC) and CNCs-rhodamine B isothiocyanate (CNCs-RBITC)) on cellular 

The research on extraction of CNCs from different sources and uniform dispersion in polymer matrices has always been an important issue in the field of bionanocomposites. The nanoscale dimensions of cellulosic fibers along with their biodegradability and 

CTB cholera toxin (B-snbunit) and UV nltraviolet. (a and b) Reprodnced with permission from C.L. Schofield, R.A. Field and D.A. Rnssell, Analytical Chemistry, 2007, 79, 4,1356. 2007, American Chemical Society [72]. c) Reproduced with permission from A. Mader, K. Gruber, R. Castelli, B.A. Hermann, 

Seeberger, J.O. Radler and M. Leisner, Nano Letters, 2011, 12,1,420. 2011, American Chemical Society [76] 

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The strategy described has been demonstrated by the in vivo labeling of proteins in both bacterial and mammalian systems thereby making it potentially useful for future bioimaging and proteomics applications [163],... 

While VFPs have boosted the applications of FRET-FLIM, chemical FRET probes should not be dismissed. The advantage of chemical probes is that they are much smaller in size and that they often have much better spectral readout than VFP probes. In Chapter 6, Amanda Cobos Correa and Carsten Schultz highlight the various small molecule-based FRET probes and their use in bioimaging. 

Nanogels are nanometer-sized hydrogel nanoparticles (less than about 100 nm) with three-dimensional networks of physically crosslinked polymer chains. They have attracted growing interest over the last decade because of their potential for applications in biomedical fields, such as DDS and bioimaging [246-249]. 

Kamimura M, Kanayama N, Tokuzen K, Soga K, Nagasaki Y (2011) Near-infrared (1550 nm) In vivo bioimaging based on rare-earth doped ceramic nanophosphors modified with PEG-b-poly (4-vinylbenzyl phosphonate). Nanoscale. doi 10.1039/ClNR10466G... 

The conversion of squaraine 19a to the rotaxane 18 D 19a causes a modest red-shift only in both absorption (10 nm) and emission (7 nm) but an approximately threefold decrease in quantum yield. The addition of two triazole rings (dye 19b) did not significantly alter the quantum yield of 17b (Table 4). A macrocycle-induced quenching effect was verified by fluorescence titration experiments adding aliquots of 18 to a solution of squaraine 17b in methylene chloride [58]. Treatment of the 18 d 17b psuedorotaxane system with the tetrabutylammonium salts of chloride, acetate, or benzoate leads to the displacement of squaraine 17b from the macrocyclic cavity and the nearly complete restoration of its fluorescence intensity. The 18-induced quenching of 17b does not support the utility of this system as a bioimaging probe however, the pseudorotaxane system 18 Z> 17b acts as an effective and selective anion sensor with NIR fluorescence. 

The squaraine rotaxanes based on the macrocycle 16b exhibit intense NIR absorption and emission maxima, and it should be possible to develop them into molecular probes for many types of photonic and bioimaging applications. In contrast, the squaraine fluorescence intensity is greatly diminished when the dye is encapsulated with macrocycle 18. The fluorescence is restored when a suitable anionic guest is used to displace the squaraine dye from a pseudorotaxane complex, which indicates that the multicomponent system might be applicable as a fluorescent anion sensor. 

Wu J, Ye Z, Wang G, Jin D, Yuan J, Guan Y, Piper J (2009) Visible-light-sensitized highly luminescent europium nanoparticles preparation and application for time-gated luminescence bioimaging. J Mater Chem 19 1258-1264... 

Sreejith, S., X. Ma, and Y. Zhao, Graphene oxide wrapping on squaraine-loadedmesoporous silica nanoparticles for bioimaging. Journal of the American Chemical Society, 2012.134(42) p. 17346-17349. 

Fig.l Schematic design of nanoparticie for bioimaging containing the fluorescent dye encapsuiated in an inorganic matrix Q surface modified with another sheii o and conjugated to biomoiecuies ... 

QDs are finding increasing application in bioimaging because of the following unique advantages over conventional contrast agents ... 

Santra S, Dutta D, Moudgil BM (2005) Functional dye-doped silica nanoparticles for bioimaging, diagnostics and therapeutics. Food Bioprod Process 83 136-140... 

Santra S, Yang H, Dutta D, Stanley JT, Holloway PH, Tan WH, Moudgil BM, Mer-icle RA (2004) TAT conjugated, FITC doped silica nanoparticles for bioimaging applications. Chem Commun, pp 2810-2811... 

In conclusion, it should be noted that fluorene derivatives 16 and 22, with large two-photon absorption cross sections, high fluorescence quantum yields and high photochemical stabihty imder one- and two-photon excitation are outstanding candidates for various linear and nonhnear optical apphcations, especially 3D fluorescence bioimaging. 

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