Manipulation of magnetic edge states in carbon quantum dots for magnetic resonance imaging and NIR-II photo-thermoelectric therapy

Abstract

The magnetic quantum phenomena triggered by electrons in carbon-based materials are challenging to decipher and exploit, thus sparking extensive research interest. Carbon quantum dots (CQDs), emerging candidates in nanomedicine, exhibit fascinating behaviors related to electron spin, relaxation, and migration. Herein, we report a magnetic edge state structure within nonmetallic CQDs that generates nitrogen hyperfine splitting at room temperature. Furthermore, a series of near-infrared (NIR) absorption bandgaps are produced based on spin–orbit coupling and dipole–dipole interactions, exhibiting potential in photothermal and thermoelectric catalysis. By modulating the surface ligands and solvent, relaxation rates are accelerated through spin averaging, which results in CQDs serving as desirable T1 contrast agents with the highest relaxivity for magnetic resonance imaging (MRI) and NIR-II cancer therapy agents. Combining these characteristics, we propose an MRI-guided approach to precision cancer therapy that offers a pathway for the rapid advancement of nanomedicine.