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摘要
A new dual mode competitive immunosensing platform for sensitive determination of alpha-fetoprotein (AFP) combined photoelectrochemical and electrochemical methods was designed on graphite carbon nitride and reduced graphene oxide (g-CN/rGO) conjugate support. To construct such versatile support, polyamidoamine dendrimer (PAAD) decorated graphene oxide (GO) as substrate was reduced via potentiostatic technology, and the prepared rGO-PAAD nanocomposite was utilized as matrix to immobilize g-CN and capture antigen, and as electron transporter to mediate electron transfer for enhancement of photoelectrochemical and electrochemical signals. And then, horseradish peroxidase labeled antibody was competitively captured onto sensing interface with free antigen in incubated solution. Photoelectrochemical signal originated from g-CN, an excellent photoactive material with large photo-induced electric response, and was amplified by rGO-PAAD nanocomposite. The resultant concentration positively related linear calibration range was from 1 pg/mL to 40 ng/mL with ultralow detection limit of 1 pg/mL. On the other hand, the enzyme-induced electrocatalytical signal amplification was produced by using hydroquinone as reactive substrate and horseradish peroxidase as reactive enzyme in existence of H2O2, which displayed a wide dynamic linear range from 0.1 ng/mL to 160 ng/mL with low detection limit of 0.1 ng/mL. Additionally, the satisfying selectivity, good reproducibility and high consistency of dual signal outputs of this designed dual-responsive immunosensor demonstrated the promising application in developing sensitive and accurate immunosensor for clinical test and disease diagnosis.
- 出版日期2016-7
- 单位福建省肿瘤医院; 福建师范大学
