Ultrasonic levitation construction of palladium doped near-infrared carbon dots as nanoprobes for carbon monoxide sensing and imaging

Abstract

Carbon monoxide (CO), as a crucial gasotransmitter and reactive carbon species, plays critical roles in regulating various physiological and pathophysiological processes, but it is also highly toxic, even at low concentrations. Combining common fluorescence imaging with a carbon dots (CDs) nanomaterial to construct nanoprobes for effective sensing and visualization of CO is of great importance. Here, we establish a smart near-infrared (NIR) nanoprobe, Pd-CDs, through a unique ultrasonic levitation method. Specifically, we show that ultrasonic levitation can be used to form CDs within 5 min and significantly redshift the emission over 150 nm to the NIR region. We also found that ultrasonic levitation can be used for optimization with an enhanced loading rate of Pd which is crucial for promoting the selectivity and sensitivity. Hence, the sensing of CO can be achieved quickly within 10 s, along with excellent selectivity, superior sensitivity and a low detection limit of 0.19 nM. Significantly, the nanoprobe exhibited low cytotoxicity and high practicability for the visual sensing and imaging of exogenous and endogenous CO in living cells. In summary, ultrasonic levitation enables the convenient construction of CDs-based smart nanoprobes with advanced photochemical and sensing properties, while also offering new insights into the effective monitoring of potential reactions involving CO in biological systems.