A network signal amplification strategy of ultrasensitive photoelectrochemical immunosensing carcinoembryonic antigen based on CdSe/melamine network as label
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Abstract
Taking advantage of CdSe/melamine network as label and Au-TiO2 as substrate, this
work developed a novel kind of signal amplification strategy for fabricating photoelectrochemical
(PEC) immunoassay. The melamine, a star-shaped triamino molecule, was firstly used
for readily capturing CdSe QDs and forming a CdSe/melamine network, which was formed
through strong interactions between the carboxyl groups of TGA-stabilized CdSe QDs
and the three amino groups of each melamine molecule. In this strategy, the primary
antibody (Ab1) was immobilized onto Au-TiO2 substrate, which made the photoelectric
conversion efficiency increase significantly. After the formed Ab2-CdSe/melamine network
labels were captured onto the electrode surface via the specific antibody-antigen
interaction, the photoelectric activity could be further enhanced via the interaction
between the Au-TiO2 substrate and CdSe/melamine network. Due to this amplification
of PEC signals and the special structure of the label, the fabricated PEC immunosensor
was applied for sensitive and specific detection of cancer biomarker carcinoembryonic
antigen (CEA), and displayed a wide linear range (0.005-1000ngmL(-1)) and low detection
limit (5pgmL(-1)). In addition, the immunosensor was performed with good stability
and reproducibility, and the results to analyze human serum samples were satisfactory.