Robust solvatochromic carbon quantum dots for selective detection of water and Sn4+ and specific lipid imaging

Developing carbon quantum dots (CQDs) with the solvatochromic effect and exploring multifunctional applications remains challenging. Herein, robust solvatochromic carbon quantum dots ( RS -CQDs) with emission shift up to ∼62 nm from yellow to red was fabricated by the hydrothermal method. The RS -CQDs was used to detect water and Sn 4+ in the linear ranges and limits of detection of 2.0–97.6% and 0.14% and 6.24–53.18 μM and 66.3 nM, respectively, and was further applied to determine Sn 4+ in practical water samples with satisfactory results. In addition, RS -CQDs exhibited bright red emission in oil media with a 9.7-fold increase in fluorescence relative to aqueous media, making them a wash-free probe for specifically staining lipids. Compared to the commercial lipid marker BODIPY 493/503, the RS -CQDs-based probe has significant advantages, such as longer emission, larger Stokes shift, and better photostability, ensuring that RS -CQDs-based marker can implement real-time and wash-free monitoring and imaging of lipids in living cells, liver tissues, zebrafish embryos, and zebrafish larvae. This study provides a novel research direction for the development of metal-doped CQDs by demonstrating RS -CQDs as the viability of fluorescence probes for water and Sn 4+ detection and the efficiency of RS -CQDs as a fluorescent marker for lipid imaging.