Dual fluorescence self-assembled multilayers bearing a fluorescent internal standard for interfacial sensing.

A novel dual fluorescence film Quartz/PSS/AO/PSS/CS/CdTe sensor was constructed based on layer-layer electrostatic attraction using CdTe as a fluorescence probe. Acridine orange is shielded effectively by sodium poly(4-styrenesulfonate) and chitosan, thus its fluorescence intensity does not change in the presence of the analyte, thereby acting as a fluorescent internal standard providing a reference signal. The ratio of dual fluorescence intensities of the film sensor is not affected by the fluctuation of the external environment factors such as excitation intensity, detector voltage of photo multiplier tube and sensor position in the cell holder. Assays based on this dual fluorescence self-assembled multilayers sensor afforded an extremely high sensitivity for DNA with greatly accuracy.