Rapid, Selective Fluorescent Determination of Copper (II) in Aqueous Solution and Living Cells Using a Dansyl-Based Click Probe

Abstract

A novel 1,2,3-triazole based dansyl fluorophore has been designed and synthesized for detecting Cu²⁺ as a fluorescent probe (P1). The probe P1 exhibited high sensitivity and selectivity for Cu²⁺ compared to other selected species in aqueous solution within a wide pH span (5 to 14), which showed that P1 may be applied in the entire alkaline pH window. The limit of detection (LOD) was measured to be as low as 5 × 10⁻⁷ mol/L for Cu²⁺. A 1:2 binding ratio and association constant of 4.6 × 10⁴ M⁻¹ between P1 and Cu²⁺ were determined. Additionally, rapid response to Cu²⁺ was demonstrated in less than 3 seconds and the linear concentration range was from 0.5 to 2.5 µmol/L. Moreover, probe P1 showed good biocompatibility and cell membrane permeability and was successfully applied for imaging Cu²⁺ in water samples and living cells, which demonstrates the application of P1 in complicated environments.

Keywords:

• Copper (II)
• dansyl-based fluorophore
• cellular imaging
• click probe

Additional information

Funding

This work was supported by National Natural Science Foundation of China (81971678, 81671756 and 81601554), Key Research Project of Science and Technology Foundation of Hunan Province (2017SK2093 and 2018GK5004), Natural Science Foundation of Hunan Province (2021JJ41008) and Changsha (kq1801063), Key Research Project of Science and Technology Foundation of Changsha Bureau (kh2201059).