A Coumarin-Based Fluorescent Probe for Ratiometric Detection of Cu2+ and Its Application in Bioimaging.

Jie Zhang,Lin Zhang,Meng-Yu Chen,Chang-Qing Qu,Cui-Bing Bai,Rui Qiao,Biao Wei,Rui-Qian Li

doi:10.3389/fchem.2020.00800

Abstract

The fluorescent probe L, based on naphthalimide-modified coumarin, was designed, synthesized, and characterized, which could recognize Cu2+ from other cations selectively and sensitively in HEPES buffer (10 mM, Ph = 7. 4)/CH3CN (1:4, V/V). When the probe L interacted with Cu2+, the color and the fluorescent intensity changed obviously and it provided the naked-eye detection for Cu2+. The recognition mode between them was achieved by Job's plot, IR, MS, SEM, and 1HNMR. In addition, test strips made from L could still interact with Cu2+ in tap water effectively. The limit of detection (LOD) of L was 3.5 × 10−6 M. Additionally, the density functional theory (DFT) calculation method was used to analyze the action mechanism of L toward Cu2+. Importantly, the fluorescent probe L could demonstrate favorable selectivity toward Cu2+ in Caenorhabditis elegans. Thus, L was considered to have some potential for application in bioimaging.

Highlights

As is known to all, copper ion (Cu2+) occupies an important place in a variety of fundamental physiological processes in organisms ranging from bacteria to mammals
Physiological pH is between 7.35 and 7.45 (Lee et al, 2010), pH 7.4 was used in the subsequent study, in which Cu2+ in adult C. elegans was detected
After the test strips were immersed in the Cu2+ solution (1.0 × 10−5 M), the test strips color change was examined directly by the naked-eye under a 365 UV lamp (Figure 8)

Summary

INTRODUCTION

As is known to all, copper ion (Cu2+) occupies an important place in a variety of fundamental physiological processes in organisms ranging from bacteria to mammals It is urgent to develop some methods for recognition toward Cu2+ Owing to their advantage over other analytical methods which include atomic absorption spectrometer (ABS) and inductively coupled plasma mass spectrometry (ICPMS), fluorescent probes have received more and more attention in the past few decades (Ge et al, 2013; Chen et al, 2017; Han et al, 2017; Wang et al, 2017; Zhou et al, 2017; Liu et al, 2018; Tian et al, 2019; Pipattanawarothai and Trakulsujaritchok, 2020). Many coumarin derivatives have been obtained to detect Cu2+ (Li et al, 2018; Roy et al, 2018; Wang Y. et al, 2018; Zhao et al, 2019; Joniak et al, 2020).

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT