Unlocking the Potential of Different Types of Biomass-Derived Carbon Dots as Fluorescence Lifetime Imaging Probes

The ongoing search for innovative and environmentally friendly luminescent materials coupled with customizable physical and chemical properties at the nanoscale positions carbon dots (CDots) as ideal candidates for photonic applications. However, even today, their rational design for specific applications remains elusive due to the unknown relationship between optical and structural properties. Therefore, this study aims to fill this gap by linking the chemical structure of the precursor and synthetic conditions to the final structural composition of the CDots and, by extension, to their optical properties. The study shows that while CDots are chemically stable, their optical properties, which are determined by the carbonaceous core and surface groups, are highly pH dependent. These properties, together with the long fluorescence lifetimes observed in living cells (>10 ns), make these biomass-derived CDots promising probes for time-resolved fluorescence imaging.