| Autor: |
Yang R; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China., Zou K; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China., Li Y; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China., Meng L; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China., Zhang X; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China., Chen J; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering , Hunan University , Changsha , 410082 , People's Republic of China. |
| Abstrakt: |
Taking the zeolitic imidazolate framework (ZIF-67) as the precursor, p-type semiconducting Co 3 O 4 -Au polyhedra were synthesized and used as the signal amplifier to construct a sensitive photoelectrochemical (PEC) sensor for caspase-3 activity assay. Here, the n-type semiconductor Bi 2 S 3 -modified indium-tin oxide (ITO) slice was used as the photoelectrode. After immobilization of the biotin-DEVD-peptide (biotin-Gly-Asp-Gly-Asp-Glu-Val-Asp-Cys) onto the Bi 2 S 3 surface, the streptavidin-labeled Co 3 O 4 -Au polyhedra were introduced to the sensing platform via the specific interaction between biotin and streptavidin. The Co 3 O 4 -Au polyhedra can not only quench the photocurrent of the Bi 2 S 3 because of the competitive consumption of electron donors and exciting light energy (p-n-type semiconductor quenching effect), but also act as peroxidase mimetics to produce catalytic precipitate. Additionally, the steric hindrance effect from the Co 3 O 4 -Au polyhedra will decrease the PEC response of the Bi 2 S 3 . Ingeniously, the precipitates can not only deposit on the ITO electrode to decrease the photocurrent of PEC sensor, but also act as electron acceptors to scavenge the photogenerated electrons of Co 3 O 4 -Au polyhedra, leading to enhanced quenching ability of the Co 3 O 4 -Au polyhedra. When caspase-3 exists, caspase-3 can specifically recognize and cleave the biotin-DEVD-peptide, resulting in the increase of PEC response. Based on the multifunctional Co 3 O 4 -Au polyhedra, caspase-3 is detected sensitively with a linear range from 0.5 to 50 ng mL -1 and limit of detection down to 0.10 ng mL -1 . The Co 3 O 4 -Au polyhedra provide a novel signal amplifier to construct PEC sensing platform and may have potential applications in bioanalysis, disease diagnostics, and clinical biomedicine. |
