Near infrared fluorescence

Europium cryptates can be associated with various acceptors, originally with a cross-linked allophycocyanin called XL665 or with small fluorescent near infrared dyes that have been selected so that their photophysical properties fit those of the europium cryptate for an efficient FRET process ... 

Absorption and Fluorescence Spectra. The absorption spectra of actinide and lanthanide ions in aqueous solution and in crystalline form contain narrow bands in the visible, near-ultraviolet, and near-infrared regions of the spectmm (13,14,17,24). Much evidence indicates that these bands arise from electronic transitions within the and bf shells in which the Af and hf configurations are preserved in the upper and lower states for a particular ion. 

Another method, called photobleaching, works on robust soHds but may cause photodecomposition in many materials. The simplest solution to the fluorescence problem is excitation in the near infrared (750 nm—1.06 pm), where the energy of the incident photons is lower than the electronic transitions of most organic materials, so fluorescence caimot occur. The Raman signal can then be observed more easily. The elimination of fluorescence background more than compensates for the reduction in scattering efficiency in the near infrared. Only in the case of transition-metal compounds, which can fluoresce in the near infrared, is excitation in the midvisible likely to produce superior results in practical samples (17). 

Kim S, Fisher B, Eisler HJ, Bawendi M (2003) Type-11 Quantum Dots CdTe/CdSe (core/sheU) and CdSe/ZnTe(core/shell) heterostructures. J Am Chem Soc 125 11466-11467 Aharoni A, Mokaii T, Popov 1, Banin U (2006) Synthesis of InAs/CdSe/ZnSe core/ shelll/shell2 structures with bright and stable near-infrared fluorescence. J Am Chem Soc 128 257-264... 

Multiphoton Fluorescence Imaging with the Near-Infrared 35 fs Laser Microscope... 

Matsuda, H., Fujimoto, Y, Ito, S., Nagasawa, Y, Miyasaka, H., Asahi, T. and Masuhara, H. (2006) Development of near-infrared 35 fs laser microscope and its application to the detection of three- and four-photon fluorescence of organic microcrystals. J. Phys. Chem. B, 110, 1091. 

Baars, M.J. and Patonay, G., Ultrasensitive detection of closely related angiotensin I peptides using capillary electrophoresis with near-infrared laser-induced fluorescence detection, Anal. Chem. 71, 667, 1999. 

Raman spectroscopy has enjoyed a dramatic improvement during the last few years the interference by fluorescence of impurities is virtually eliminated. Up-to-date near-infrared Raman spectrometers now meet most demands for a modern analytical instrument concerning applicability, analytical information and convenience. In spite of its potential abilities, Raman spectroscopy has until recently not been extensively used for real-life polymer/additive-related problem solving, but does hold promise. Resonance Raman spectroscopy exhibits very high selectivity. Further improvements in spectropho-tometric measurement detection limits are also closely related to advances in laser technology. Apart from Raman spectroscopy, areas in which the laser is proving indispensable include molecular and fluorescence spectroscopy. The major use of lasers in analytical atomic... 

Cherukuri, P. et al. (2006) Mammalian pharmacokinetics of carbon nanotubes using intrinsic near-infrared fluorescence. Proceedings of the National... 

An interesting imaging probe Id that can selectively target bacteria was recently reported by Smith et al. [31] also based on a heptamethine chromophore. The probe is composed of a bacterial affinity group, which is a synthetic zinc (II) coordination complex that targets the anionic surfaces of bacterial cells and a near infrared dye. The probe allowed detection of Staphylococcus aureus in a mouse leg infection model using whole animal near-infrared fluorescence imaging. 

Recently, SETA BioMedicals has developed a new near-infrared squaraine-based label Seta-633, which can be used to study the interaction between low-molecular-weight analytes and proteins using fluorescence lifetime as the readout parameter [19]. This label exhibits lower quantum yields and shorter fluorescence lifetimes when free in solution, but these values substantially increase upon interaction with proteins, which is contrary to tracers like Cy5 or Alexa 647. It was demonstrated in a model assay that a biotinylated Seta-633 binds to anti-biotin with high specificity. Importantly, the lifetime of Seta-633-biotin increases about 2.76 fold upon binding to a specific antibody (anti-biotin, MW =160 kDa), while the titration with BSA or nonspecific antibody does not result in a noticeable change in lifetime (Fig. 13). The label is compatible with readily available light sources (635 nm or 640 nm lasers) and filter sets (as for Cy5 or Alexa 647) and its... 

Miller JN (2008) Long-wavelength and near-infrared fluorescence state of the art, future applications, and standards. Springer Ser Fluoresc 5 147-162... 

Narayanan N, Strekowski L, Lipowska M, Patonay G (1995) A new method for the synthesis of heptamethine cyanine dyes synthesis of new near infrared fluorescent labels. J Org Chem 60 2391-2395... 

Meadows F, Narayanan N, Patonay G (2000) Determination of protein-dye association by near infrared fluorescence-detected circular dichroism. Talanta 50 1149-1155... 

Arun KT, Ramaiah D (2005) Near-infrared fluorescent probes synthesis and spectroscopic investigations of a few amphiphilic squaraine dyes. J Phys Chem A 109 5571-5578... 

Basheer MC, Santhosh U, Alex S, Thomas KG, Suresh CH, Das S (2007) Design and synthesis of squaraine based near infrared fluorescent probes. Tetrahedron 63 1617-1623... 

Umezawa K, Citterio D, Suzuki K (2007) A squaraine-based near-infrared dye with bright fluorescence and solvatochromic property. Chem Lett 36 1424—1425... 

Matveeva EG, Terpetschnig EA, Stevens M, Patsenker L, Kolosova OS, Gryczynski Z, Gryczynski I (2009) Near-infrared squaraine dyes for fluorescence enhanced surface assay. Dyes Pigm 80 41 16... 

Povrozin YA, Markova LI, Tatarets AL, Sidorov VI, Terpetschnig EA, Patsenker LD (2009) Near-infrared, dual-ratiometric fluorescent label for measurement of pH. Anal Biochem 390 136-140... 

Umezawa K, Nakamura Y, Makino H, Citterio D, Suzuki K (2008) Bright, color-tunable fluorescent dyes in the visible-near-infrared region. J Am Chem Soc 130 1550-1551... 

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