Magnolia denudata leaf-derived near-infrared carbon dots as fluorescent nanoprobes for palladium(Ⅱ) detection and cell imaging

• Near-infrared carbon dots are synthesized using an eco-friendly and facile approach with narrow FWHM. • A Near-infrared nanoprobe exhibits high selectivity and stability for the detection of palladium ions in aqueous solution with a detection limit of 85.3 nM. • This nanoprobe shows high biocompatibility and is employed to monitor Pd 2+ in Li-7 living cells. In this work, an eco-friendly unique approach was used to synthesize near-infrared carbon dots (NIR-CDs) from Magnolia denudata leaves. The as-prepared NIR-CDs showed a stable near-infrared emission with peak at about 678 nm and narrow full width at half maximum (FWHM), which was utilized as a fluorophore in a fluorescent nanoprobe after modification with Pluronic F-127 for detection of palladium ion (Pd 2+ ). The resulting nanoprobe diaplayed admirable performances for detecting Pd 2+ including high selectivity, excellent water solubility, and stability. The fluorescence intensity of the nanoprobe was selectivity quenched by Pd 2+ within the scope of 0–200 μM. In addition, the limit of detection (LOD) was 85.3 nM. Moreover, the constructed nanoprobe had an approving assay performance in real water samples. Finally, the nanoprobe demonstrated low toxicity and could be utilized to monitor Pd 2+ in Li-7 cells.