Scheme 1. Fabrication of Self-Propelled GQD–MRs and Their Exploitation as Dynamic Biocarriers for the Optical “On-the-Fly” DNA Determination.

(A) GQD–MRs were synthesized via membrane-assisted electrodeposition of (i) GQDs (outer layer), (ii) Ni (middle layer), and (iii) Pt (inner layer). (B) Biofunctionalization of GQD–MRs with a biomarker (i.e., FAM-L probe) via π-stacking interactions, where the resulting FAM-L@GQD–MRs (dynamic biocarriers) promote a quenching in the fluorescence activity of the probe. The optical analytical assay relies on “On-the-Fly” DNA determination using different concentrations of a complementary DNA target under fuel-induced motion (1% v/v H₂O₂), where the DNA hybridization process between the probe and the target derives in an FL recovery.