Bright green fluorescent carbon dots: Smartphone-assisted sensing platform for arsenic detection in water and mitochondrial-targeted imaging

초록

Arsenic (As3+) is a ubiquitous heavy metal pollutant, posing serious threats to ecosystems and human health. As a result, there is a growing demand for rapid detection of As3+ in environmental water matrices. In this study, we presented a fluorescent system based on nitrogen-doped green emissive carbon dots (gCDs), prepared using ophenylenediamine and thionin acetate. Upon excitation at 415 nm, the gCDs exhibited strong fluorescence at 529 nm. This fluorescence could be effectively quenched by As3+ species, ascribed to the static quenching effect, resulting in an obvious color change of gCDs from bright green to pale brown. The designed fluorescent system demonstrated ultrahigh sensitivity for As3+ sensing, with a limit of detection (LOD) of 9.11 nM. Besides, it exhibited excellent selectivity towards As3+ and strong resistance to interference from other environmentally relevant metal ions. Furthermore, a portable visual sensing platform was developed by integrating the fluorescence of gCDs with a smartphone. Using its color recognition application, the smartphone could analyze the quenching-induced color change and convert it into digital data, achieving a reasonably good LOD of 7.58 mu M. The gCDs were suitable for recognizing As3+ species in environmental water. In addition, due to their robust optical stability and low cytotoxicity, the gCDs were successfully utilized for cellular imaging. The gCDs system, as a bioimaging probe, selectively labeled mitochondria and enabled the detection of As3+ within mitochondria, highlighting its potential for bioimaging applications.

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