Selective Detection of Cu⁺ Ions in Live Cells via Fluorescence Lifetime Imaging Microscopy

Abstract

Copper is an essential trace element in living organisms with its levels and localisation being carefully managed by the cellular machinery. However, if misregulated, deficiency or excess of copper ions can lead to several diseases. Therefore, it is important to have reliable methods to detect, monitor and visualise this metal in cells. Herein we report a new optical probe based on BODIPY, which shows a switchon in its fluorescence intensity upon binding to copper(I), but not in the presence of high concentration of other physiologically relevant metal ions. More interestingly, binding to copper(I) leads to significant changes in the fluorescence lifetime of the new probe, which can be used to visualize copper(I) pools in lysosomes of live cells via fluorescence lifetime imaging microscopy (FLIM).

Lifetime‐Based Responsive Probes: Design and Applications in Biological Analysis

“…Priessner et al. designed a BODIPY‐based fluorescent probe FLCS1, and its structural formula is shown in Figure 9a [54] . When the NS 4 copper(I) acceptor in FLCS1 binds to copper(I), the fluorescence lifetime of the probe increases significantly (Figure 9b).…”

“…FLIM images of cells (c) before and (d) after incubated with Cu‐GTSM. Reproduced with permission [54] . Copyright 2021, Wiley‐VCH.…”

“…BODIPY-based fluorescent probe FLCS1, and its structural formula is shown in Figure 9a. [54] When the NS 4 copper(I) acceptor in FLCS1 binds to copper(I), the fluorescence lifetime of the probe increases significantly (Figure 9b). To verify the capacity of FLCS1 to detect copper(I) in cells, they use the release agent Cu-GTSM to increase the cellular concentration of copper(I).…”

Copper depletion combined with photothermal therapy suppresses breast cancer

“…[7][8][9] This kind of chemodynamic therapy has been widely used in antitumor research. [10][11][12] In addition, the previous studies have demonstrated that copper can promote the growth of endothelial cells and angiogenesis. [13][14][15] Therefore, reducing the content of copper in cells via copper chelators can inhibit the growth of cells and angiogenesis.…”

Lifetime Determination Algorithms for Time-Domain Fluorescence Lifetime Imaging: A Review

“…Fluorescence lifetime imaging (FLIM) is a vital and versatile technique for assessing molecular microenvironments of fluorophores in living cells, such as pH, O 2 , viscosity, temperature, or ion concentrations [1,2]. FLIM can be a powerful "quantum ruler" to measure subnanometer protein conformational changes and interactions by quantifying the occurrence of Förster Resonance Energy Transfer (FRET) [3][4][5][6][7].…”