Enrichment-enhanced detection strategy in the optimized monitoring system of dopamine with carbon dots-based probe

The complexity of living environment system demands higher requirements for the sensitivity and selectivity of the probe. Therefore, it is of great importance to develop a universal strategy for high-performance probe optimization. Herein, we propose a novel “Enrichment-enhanced Detection” strategy and use carbon dots-dopamine detection system as a representative model to evaluate its feasibility. The composite probe carbon dots (CDs)-encapsulated in glycol-chitosan (GC) (i.e., CDs@GC) was obtained by simply mixing GC and CDs through noncovalent interactions, including electrostatic interactions and hydrogen bonding. Dopamine (DA) could be detected through internal filter effect (IFE)-induced quenching of CDs. In the case of CDs@GC, noncovalent interactions (electrostatic interactions) between GC and the formed quinone (oxide of DA) could selectively extract and enrich the local concentration of DA, thus effectively improving the sensitivity and selectivity of the sensing system. The nanosensor had a low detection limit of 3.7 nmol/L, which was a 12-fold sensitivity improvement compared to the bare CDs probes with similar fluorescent profiles, proving the feasibility of the “Enrichment-enhanced Detection” strategy. Further, to examine this theory in real case, we designed a highly portable sensing platform to realize visual determination of DA. Overall, our work introduces a new strategy for accurately detecting DA and provides valuable insights for the universal design and optimization of superior nanoprobes.