title: Development of spiropyran-based electrochemical sensor via simultaneous photochemical and target-activatable electron transfer.
abstract: In traditional electrochemical sensors, the electrochemical signal transduction of the redox-active material is usually controlled by the analytical target. Due to non-specific interaction between the redox mediator and the target, false signal by single stimulus may not be avoided. To address this issue, we have developed a new electrochemical sensor that uses a functional spiropyran, an important class of photo and thermochromic compounds, as both recognition receptor and latent redox mediator, to realize simultaneous photochemical and target-modulated electron transfer. As a proof of principle, β-galactosidase was chosen as a model target. The new synthesized spiropyran probe, SP-β-gal, undergoes reversibly structural isomerization to form merocyanine under UV light irradiation. After the glycosidic bond being cleaved by β-galactosidase, the opened merocyanine of SP-β-gal forms redox-active 2-(2.5-dihydroxystyryl)-1.3.3-trimethyl-3H-indolium, and thus produces a pair of reversible redox current peaks under the electrochemical scanning. To amplify the detection signal, SP-β-gal was self-assembled with single-walled carbon nanotubes (SWCNTs) on the surface of glass carbon electrode. Kinetics experiments confirm that the probe is an ideal candidate for the determination of different concentrations of β-galactosidase digestion kinetics. Further, the SP-β-gal/SWCNTs-modified electrode is chemically stable in complex biological fluids. It was successfully applied to monitor β-galactosidase activity in the 10% calf thymus. This work represents not only a significant step forward in the further development of low-dimensional carbon nanomaterials/small organic molecular probes-based electrochemical biosensors, but also a new platform which may be extended to the assay of other enzyme such as β-D-glycosidase and so on by translating the biorecognition into electrochemical signal responses.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Tao
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Duan
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. Electronic address: Yangrh@pku.edu.cn.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Yang
mesh_terms: D000818:Animals; D001578:Benzopyrans; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D055664:Electrochemical Techniques; D004579:Electron Transport; D007211:Indoles; D015335:Molecular Probes; D037742:Nanotubes, Carbon; D009574:Nitro Compounds; D055668:Photochemical Processes; D001616:beta-Galactosidase / Q000032:analysis
chemical_list: D001578:Benzopyrans; D007211:Indoles; D015335:Molecular Probes; D037742:Nanotubes, Carbon; D009574:Nitro Compounds; C088184:spiropyran; D001616:beta-Galactosidase
keywords: Electrochemistry detection; Photo-activation; Spiropyran; Target-activation; β-galactosidase