title: A dual-potential electrochemiluminescence ratiometric sensor for sensitive detection of dopamine based on graphene-CdTe quantum dots and self-enhanced Ru(II) complex.
abstract: A novel dual-potential ratiometric electrochemiluminescence (ECL) sensor was designed for detecting dopamine (DA) based on graphene-CdTe quantum dots (G-CdTe QDs) as the cathodic emitter and self-enhanced Ru(II) composite (TAEA-Ru) as the anodic emitter. TAEA-Ru was prepared by linking ruthenium(II) tris(2,2'-bipyridyl-4,4'-dicarboxylato) with tris(2-aminoethyl)amine. Firstly, 3-aminopropyltriethoxysilane founctionalized G-CdTe QDs was used as the substrate for capturing target DA via the specific recognition of the diol of DA to the oxyethyl group of APTES. Then, Cu2O nanocrystals supported TAEA-Ru was further bound by the strong interaction between amino groups of DA and carboxyl groups of the Cu2O-TAEA-Ru. With the increase in DA concentration, the loading of Cu2O-TAEA-Ru at the electrode increased. As a result, the anodic ECL signal from TAEA-Ru increased, and the cathodic ECL signal from G-CdTe QDs/O2system decreased correspondingly. Such a decrease was resulted from the ECL resonance energy transfer (RET) from G-CdTe QDs to TAEA-Ru as well as the dual quenching effects of Cu2O to G-CdTe QDs, namely the ECL-RET from G-CdTe QDs to Cu2O and the consumption of coreactant O2by Cu2O. Based on the ratio of two ECL signals, the determination of DA was achieved with a linear range from 10.0 fM to 1.0nM and a detection limit low to 2.9 fM (S/N=3). The combination of G-CdTe QDs/O2and TAEA-Ru would break the limitation of the same coreatant shared in previous ECL ratiometric systems and provide a potential application of ECL ratiometric sensor in the detection of biological small molecules with the assistance of the dual molecular recognition strategy.
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Fu
authors.affiliation: Department of Endocrinology, 9 th People's Hospital of Chongqing, Chongqing 400700, PR China.
authors.forename: Xingrong
authors.initials: X
authors.lastname: Tan
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: cshong@swu.edu.cn.
authors.forename: Shihong
authors.initials: S
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques; D019187:Cadmium Compounds / Q000737:chemistry; D004298:Dopamine / Q000737:chemistry / Q000302:isolation & purification*; D006108:Graphite / Q000737:chemistry*; D008163:Luminescent Measurements; D053758:Nanoparticles / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D006108:Graphite; D012428:Ruthenium; D013691:Tellurium; C028337:cadmium telluride; D004298:Dopamine
keywords: Electrochemiluminescence; Graphene-CdTe quantum dots; Ratiometric sensor; Self-enhanced Ru(II) complex