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Radiolabeling of peptides with the short-lived positron emitter fluorine-18 is usually a challenging endeavour. Conventional radiolabeling reactions mostly require fairly large amounts of peptides as labeling precursors, and extensive synthesis times. Intrinsic advantages of microfluidic technology permit to overcome these hurdles. Herein, we describe how microfluidic technology combined with [18F]FDG as readily available PET radiotracer allows for fast and high yielding radiolabeling reactions of peptides with fluorine-18. [ABSTRACT FROM AUTHOR]

The first application of sulfo-click chemistry with 18F-labeled thio acids is described. The simple one-pot/three-component reaction proceeded rapidly within 30 min using mild reaction conditions to give various 18F-labeled small molecule N-acylsulfonamides in radiochemical conversions of 38–99%, and radiolabeled peptides in 20–25% isolated and decay-corrected radiochemical yields. [ABSTRACT FROM AUTHOR]

The study describes the Sonogashira cross-coupling reaction with 4-[18F]fluoroiodobenzene ([18F]FIB) as novel and efficient method for rapid labelling of peptides with the short-lived positron emitter fluorine-18. [ABSTRACT FROM AUTHOR]

The radiometal 64Cu is now widely used in the development of diagnostic imaging agents for positron emission tomography (PET). The present study has led to the development and evaluation of a novel chelating agent for 64Cu: the new monothiourea tripodal ligand 1-benzoyl-3-{6-[(bis-pyridin-2-ylmethyl-amino)-methyl]-pyridin-2-yl}-thiourea (MTUBo). X-ray crystallographic analysis has shown this ligand forms a mononuclear complex with copper(ii) and co-ordinates via a trigonal bipyramidal N4S array of donor atoms. Promisingly, cell uptake studies revealed that 64Cu-MTUBo selectively accumulates in EMT-6 cells incubated under hypoxic conditions which may result from its relatively high CuII/I redox potential. Small-animal PET imaging and ex vivo biodistribution studies in EMT-6 tumor bearing BALB/c mice revealed significant tumor uptake after 1 h p.i., yielding tumor-to-muscle (T/M) and tumor-to-blood (T/B) ratios of 8.1 and 1.1, respectively. However, injection of 64Cu-acetate resulted in similar uptake indicating that the observed uptake was most likely non-specific. Despite showing high in vitro stability, it is likely that in vivo the complex undergoes transchelation to proteins within the blood in a relatively short timeframe. For comparison, the hypoxia imaging agent 64Cu-ATSM was also evaluated in the same murine tumor model and showed about 60% higher tumor uptake than 64Cu-MTUBo. [ABSTRACT FROM AUTHOR]

The study describes for the first time the application of Cu(I)-mediated 1,3-dipolar [3+2]cycloaddition for the labelling of proteins with the short-lived positron emitter fluorine-18 as exemplified with azide-functionalized human serum albumin (HSA). [ABSTRACT FROM AUTHOR]