A near infrared fluorescent probe for detection and bioimaging of zinc ions and hypochlorous acid

Abstract

It is of great significance to monitor zinc ions (Zn²⁺) and hypochlorous acid (HClO) conveniently in disease diagnosis and environmental protection. Herein, we successfully prepared a near-infrared fluorescent probe based on dicyanoisophorone derivative and methyl hydrazate by Schiff base reaction for effective detection of Zn²⁺ and HClO. After binding with Zn²⁺ at a molar ratio of 1:1, the fluorescence intensity (λ_ex = 482 nm, λ_em = 653 nm) of the probe was significantly enhanced, thus achieving quantitative detection and optical cell imaging of Zn²⁺. The complexation constant (K) of the probe with Zn²⁺ was 2.34 × 10⁴ M^-1. The response time of the probe for Zn²⁺ was less than 20 s and the detection limit was 15.3 nM. Moreover, this probe also showed a specific response to HClO. After interacting with HClO, the fluorescence intensity of the probe was increased significantly with a red shift of the emission wavelength from 670 nm to 705 nm (λ_ex = 550 nm). The response time and the detection limit of probe for HClO were 4 min and 1.39 μM, respectively. The probe was successfully applied for visual bioimaging of Zn²⁺ and HClO inside living cells. The recoveries of Zn²⁺ and HClO using the probe in actual water samples were satisfactory.

Keywords: Fluorescence probe; HClO; ICT; Near infrared; PET; Zn(2+).