Imaging, applications

The brain uptake properties of 99m Tc-complexes with the MRP-20 ligand make it and its derivatives potential candidates for rCBF imaging applications. MRP-20 forms a neutral-lipophilic complex with the 99mTcO+3 core by loss of three ionizable protons from the ligand backbone (Fig. 3) [16]. "mTc-MRP-20 and several of its analogues show high brain uptake and retention and exhibit regional cerebral deposition patterns that are related to rCBF [16], This complex is in clinical trials in Europe. 

Chang CJ, Javorski J, Nolan EM, Shaeng M, Lippard SJ (2004) A tautomeric zinc sensor for ratiometric fluorescence imaging application to nitric oxide-release of intracellular zinc. Proc Natl Acad Sci USA 101 1129-1134... 

The use of doped and undoped silica aerogels as multifunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications has been reported.278 Results have been presented on the PL spectra of undoped silica aerogels and aerogels doped with Er3+, rhodamine, and fluorescein.278... 

DTPA has also been used in the peptide-based " in-DTPA-octreotide. Octreotide is a shortened peptide analog of somatostatin designed to be more stable in vivo. Radiolabeling of octreotide for diagnostic imaging applications with radioisotopes for PET or SPECT has been investigated,... 

Noise can be also introduced by biochemical heterogeneity of the specimen. This can be a major cause of uncertainty in biological imaging. The high (three-dimensional) spatial resolution of fluorescence microscopy results in low numbers of fluorophores in the detection volume. In a typical biological sample, the number of fluorophores in the detection volume can be as low as 2-3 fluorophores for a confocal microscope equipped with a high NA objective at a fluorescent dye concentration of 100 nM. This introduces another source of noise for imaging applications, chemical or molecular noise, related to the inherent randomness of diffusion and the interaction of molecules. 

QDs excited by single or multiple photons exhibit multixponen-tial decays, in our hands generally with two components of <10 and 10-25 ns. This property renders the nanoparticles useful reagents for the systematic modulation of emission via a technique we have denoted as photochromic FRET (pcFRET, Fig. 12.5 see [1, 2, 134]). The method was developed in order to circumvent inherent limitations in the quantitative determination of FRET in cells, particularly in imaging applications. We have classified pcFRET as a member of the family of so-called acceptor depletion methods [1, 2] due to the reversible change in the structure, and thus spectroscopic properties, of the photochromic compound (e.g., a diheteroarylethene) serving as the FRET acceptor. The key... 

The second requirement is related to chemical imaging applications. Very flat samples are required to avoid problems of depth of field. Even if this is common to every imaging technique, it is in this case coupled with surface pollution problems. Sample preparation must then lead to flat surfaces without surface pollution. For cultural heritage samples,... 

Although nuclear magnetic resonance (NMR) spectroscopy has been used to study a variety of lanthanide based systems like contrast agents for medical imaging applications, only a handful of studies on lanthanide SMMs using NMR have been performed to date. These include the neutral [Ln(Pc)2]°(Ln = Dy or Tb)... 

The polyvalent nature of dendrimers has been investigated as vehicles for carrying multiple chelator groups to enhance signals in various imaging applications (Barthand Soloway, 1994 Yoo et al., 1999 Kobayashi et al., 2000, 2001 Sato et al., 2001). In addition, in certain chelate-dendrimer constructs, excess amines on the dendrimer surface can aid in the cellular uptake process through charge-mediated endocytosis. 

Figure 15.17 An amino-PEG-pyrrolidine derivative of carbon nanotubes can be used to couple metal chelating groups, such as DTPA. Subsequent coordination of mIn results in an indium chelate that can be used for imaging applications.

Printing Materials. The application of photopolymer technology to a wide variety of imaging applications in the printing industry is a quite important. Most printing plates and pre-press proofing products used today are based on, or utilize some element of, photopolymer chemistry. 

Fig. 2. Schematic diagrams of alternative force feedback modes. (A) Illustrates noncontact atomic force microscope feedback. (B) Shear-force feedback frequently used in NSOM imaging applications. From Paesler and Moyer (41), with permission.

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