A high-affinity fluorescence probe for copper(II) ions and its application in fluorescence lifetime correlation spectroscopy

• Published in: Analytical and bioanalytical chemistry 2019-06, Vol.411 (15), p.3229-3240
• Main Authors: Grüter, Andreas, Hoffmann, Michael, Müller, Rolf, Wohland, Thorsten, Jung, Gregor
• Format: Article
• Language: English
• Subjects: Affinity; Analytical Chemistry; Biochemistry; Boron Compounds - chemical synthesis; Boron Compounds - chemistry; Cations; Cations, Divalent - analysis; Characterization and Evaluation of Materials; Chemical detectors; Chemical properties; Chemistry; Chemistry and Materials Science; Coordination compounds; Copper; Copper - analysis; Copper compounds; Copper ions; Fluorescence; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Fluorescent indicators; Food Science; Heavy metals; Homeostasis; Humans; Identification and classification; In vivo methods and tests; Ions; Laboratory Medicine; Monitoring/Environmental Analysis; Neurodegenerative diseases; Neurological diseases; Oligopeptides - chemical synthesis; Oligopeptides - chemistry; Organisms; Paper in Forefront; Spectrometry, Fluorescence - methods; Spectroscopy; Spectrum analysis; Transition metals
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-019-01798-y

Copper is one of the most important transition metals in many organisms where it catalyzes a manifold of different processes. As a result of copper’s redox activity, organisms have to avoid unbound ions, and a dysfunctional copper homeostasis may lead to multifarious pathological processes in cells with very severe ramifications for the affected organisms. In many neurodegenerative diseases, however, the exact role of copper ions is still not completely clarified. In this work, a high-affinity and highly selective copper probe molecule, based on the naturally occurring tetrapeptide DAHK is synthesized. The sensor (log K D  = − 12.8 ± 0.1) is tagged with a fluorescent BODIPY dye whose fluorescence lifetime distinctly decreases from 5.8 ns ± 0.2 ns to 0.4 ns ± 0.1 ns on binding to copper(II) cations. It is shown by using fluorescence lifetime correlation spectroscopy that the concentration of both probe and probe-copper complex can be simultaneously measured even at nanomolar concentration levels. This work presents a possible starting point for a new type of probe and method for future in vivo studies to further reveal the exact role of copper ions in organisms. Graphical abstract