Efficient fluorescence resonance energy transfer-based ratiometric fluorescent probe for detection of dopamine using a dual-emission carbon dot-gold nanocluster nanohybrid

A ratiometric fluorescent probe is prepared based on fluorescence resonance energy transfer (FRET) for fluorometric determination of dopamine (DA). The ratiometric fluorescent probe (CQDs-AuNCs) was obtained by coupling amidated modified carbon quantum dots (CQDs) with bovine serum albumin-coated gold nanoclusters (AuNCs), which had two emission peaks of 446 nm and 670 nm and displayed purple fluorescence under the excitation of 397 nm. The probe is based on the performance that the purple fluorescence of the CQDs-AuNCs is quenched by DA due to the electron transfer from CQDs to DA and thus inhibiting the FRET process between CQDs and AuNCs. The ratiometric fluorescent probe is selective for DA with a detection limit of 2.66 nM. Response is linear in the ranges of 2.66 nM–0.18 mM, 0.511–3.79 mM and 4.87–13.1 mM. The method has good anti-interference ability even if the concentration of the interfering substance is 5 times higher than that of DA. Due to the high sensitivity and selectivity of the ratiometric fluorescent probe, this method was successfully used to measure DA in serum samples.