Near-infrared fluorescence imaging

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. 

Chen X, Conti PS, Moats RA (2004) In vivo near-infrared fluorescence imaging of integrin av(33 in brain tumor xenografts. Cancer Res 64 8009-8014... 

I. Hilger Y. Leistner, A. Bemdt, C. Fritsche, K. Michael, H. Hartwig, K. Werner, and A. Kaiser, Near-Infrared Fluorescence Imaging of HER-2 Protein Over-Expression in Tumour Cells, Eur. Radiol, 14,1124 (2004). 

Y. Chen, X. Intes, and B. Chance, Development of High-Sensitivity Near-Infrared Fluorescence Imaging Device for Early Cancer Detection, Biomed. Instrum. Technol, 39(1), 76 (2005). 

Y. Wu, W. Cai, and X. Chen, Near-Infrared Fluorescence Imaging of Tumor Integrin av 33 Expression with Cy7-Labeled RGD Multimers, Mol. Imaging Biol, 8,226 (2006). 

Petrovsky A, ScheUenberger E, Josephson L, Weissleder R, Bogdanov A Jr. Near-infrared fluorescent imaging of tumor apoptosis. Cancer Res 2003 ... 

Weissleder, R., Tung, C. H., Mahmood, U. and Bogdanov, A., Jr. (1999). In vivo imaging of tumors with protease-activated near-infrared fluorescent probes. Nat. Biotechnol. 17, 375-378. 

References [52-54] do not include any data directly comparing squaraine rotaxanes with common cyanine dyes such as Cy5 (GE Healthcare) and Alexa 647 (Life Technologies). Nevertheless, from the available data it can be concluded that squaraine rotaxanes are remarkably resistant to chemical and photochemical degradation, and likely to be very useful as a versatile fluorescent scaffold for constructing various types of highly stable, red and near infrared (NIR) imaging probes and labels. 

Johnson JR, Fu N, Arunkumar E, Leevy WM, Gammon ST, Piwnica-Worms D, Smith BD (2007) Squaraine rotaxanes superior substitutes for Cy-5 in molecular probes for near-infrared fluorescence cell imaging. Angew Chem Int Ed 46 5528-5531... 

Visible and near-infrared fluorescent emitters are being applied in the medical imaging fleld. Examples include cancer diagnosis, ophthalmology, cardiac surgery and in the treatment of bums. (See also Chapter 4, section 4.6). 

Laser-induced fluorescence (LIF) has also been utilized as a highly sensitive detection principle for CE [48-51]. However, while the LIF detector is now able to achieve zeptomole (10 21) detection limits, conventional derivatization techniques are inefficient at these exceptional levels [52]. Also, CE has successfully been coupled with mass spectrometry (MS) [53], nuclear magnetic resonance (NMR) [54, 55], near-infrared fluorescence (NIRF) [56, 57], radiometric [58], flame photometric [59], absorption imaging [60], and electrochemical (conductivity, amperometric, and potentiometry) [61-63] detectors. A general overview of the main detection methods is shown is Table 1 [64]. 

Sevick-Muraca, E.M., Houston, J.P. and Gurfinkel, M. (2002) Fluorescence-enhanced, near infrared diagnostic imaging with contrast agents. Curr. Opin. Chem. Biol., 6, 642-650. 

A.B. Thompson, E.M. Sevick-Muracka, Near-infrared fluorescence contrast-enhanced imaging with intensified charge-coupled device homodyne detection measurement precision and accuracy, J. Biomed. Opt. 8, 111-120 (2003)... 

L. Josephson, M. F. Kircher, U. Mahmood, Y. Tang, and R. Weissleder, Near-infrared fluorescent nanoparticles as combined MR/optical imaging probes, Bioconjug. Chem., 13 (2002) 554—560. 

Z. Yang, S. Zheng, W. J. Harrison, J. Harder, X. Wen, J. G. Gelovani, A. Qiao, C. Li, Long-circulating near-infrared fluorescence core-cross-linked polymeric micelles synthesis, characterization, and dual nuclear/optical imaging. Biomacromolecules, 2007, 8, 3422-3428. 

A series of fatty acids (FAs) were conjugated with polyethylenimine (PEI 25 kDa) (Figure 20.2). A near-infrared fluorescence probe, IR820, was used to study in vivo and ex vivo the brain targeting ability of these fatty acid-PEI conjugates (FA-PEIs). Brain uptake of FA-PEI(25 kDa)/rhodamine-6-iso-thiocyanate (RITC)-labeled DNA nanoparticles was investigated via a fluorescence imaging method. 

Jaffer, F.A., et al. Two-dimensional intravascular near-infrared fluorescence molecular imaging of inflammation in atherosclerosis and stent-induced vascular injury. Journal of the American College of Cardiology 57(25), 2516-2526 (2011)... 

Messerli SMPS, Tang Y, Shah K, Cortes ML, Murthy V, et al. A novel method for imaging apoptosis using a caspase-1 near-infrared fluorescent probe. Neoplasia 2004 6 95. Kagan CRMC, Nirmal M, Bawendi MG. Electronic energy transfer in CdSe quantum dot solids. Phys Rev Lett 1996 76 1517. 

Pu, K.-Y Li, K. Liu, B. A molecular brush approach to enhance quantum yield and suppress nonspecific interactions of conjugated polyelectrolyte for targeted far-red/near-infrared fluorescence cell imaging. Adv. Funct. Mater. 2010,17,2770-2777. 

C.-H. Tung, Y. Lin, W. K. Moon, and R. Weissleder, A Receptor-Tai eted Near-Infrared Fluorescence Probe for In Vivo Tumor Imaging ChemBioChem, 8, 784 (2002). 

N. Y. Morgan et al., Real time in vivo non-invasive optical imaging using near-infrared fluorescent quantum dots. Academic Radiology, 12(3), 313-323 (2005). 

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