Well-defined organic fluorescent nanomaterials with AIE characteristics for colorimetric/UV-vis/fluorescent multi-channel recognition of Zn2+ with multiple applications in plant cells and zebrafish

Abstract

Small molecular organic fluorescent materials have attracted extensive attention and have many applications owing to their excellent properties. However, the practical applications of many organic fluorescent materials are significantly limited by their complex synthesis and post-processing methods and single functions. In this paper, a small molecular organic fluorescent material (NC) based on coumarin derivatives linked by a Schiff base is designed using simple synthesis and post-processing methods. NC shows excellent aggregation induced luminescence enhancement (AIE) properties in mixed solution systems (V_HEPES : V_EtOH) with different water fractions (f_w) of 0%–40% and displays good advantages in terms of the colorimetric/UV-vis/fluorescent multi-mode recognition of Zn²⁺ for use as a probe with high specificity and selectivity, good time stability and low detection limit (DOL = 0.026 µM, R² = 0.9909) in an aqueous solution. NC solid powder also shows a yellow-green fluorescence and can also be used to recognize ground solid zinc chloride powder (ZnCl₂). NC can be combined with a paper strip and polymer film (polyurethane) to detect Zn²⁺ through a color change. Interestingly, NC exhibits a superior fluorescence effect in the inner epidermis of onion scales under a fluorescence microscope. Importantly, NC has a lower hemolytic effect (<0.3%) and has been successfully used in vivo in zebrafish embryos and zebrafish for exogenous Zn²⁺ fluorescence detection and imaging. The simple structure and versatility of NC provides a convenient approach for the development of multifunctional materials and the expansion of their wider application fields.