Nanosensing of Metal Cations in Water with Carbon Dots: Insights from Molecular Dynamics

KA Kozhushnyi and AM Vervald and TA Dolenko, JOURNAL OF PHYSICAL CHEMISTRY C, 129, 19429-19439 (2025).

DOI: 10.1021/acs.jpcc.5c04054

This study investigates the mechanisms of metal cation nanosensing in water based on the photoluminescence spectra of carbon dots (CDs), using molecular dynamics (MD) simulations and experimental data analysis. Two types of CDs synthesized hydrothermally from citric acid and ethylenediamine were studied: with polyfunctional and carboxylated surfaces. MD simulations revealed that metal cations (Al3+, Cr3+, Fe3+, Ni2+, Pb2+, Zn2+, and Cu2+) interact with surface carboxyl, hydroxyl, and amino groups of CDs without forming stable complexes, indicating a dynamic mechanism of photoluminescence quenching. It was found that ion interactions with surface groups of CDs usually occur through 1 to 3 hydration shells separating the cations from the CD surface. Experimental photoluminescence quenching data confirmed the simulation results, showing different quenching efficiencies for each cation, which correlated with MD-derived interaction strengths. The high correlation between theoretical and experimental data on the dynamic type of interaction confirms the potential of CDs to be used as "reusable" optical nanosensors for detecting metal cations in water in environmental monitoring and biomedical applications.

Return to Publications page