Detection of Echinococcus granulosus antigen by a quantum dot/porous silicon optical biosensor.

Highly sensitive labeled detection of Echinococcus granulosus using colloidal quantum dots (QDs) based on a porous silicon Bragg mirror sensor are demonstrated. Rabbit anti-p38 labeled CdSe/ZnS QDs was infiltrated in porous silicon pores immobilized Egp38 antigen. QD-antibodies are specifically bound to antigens linked covalently to the pore walls of PSi after the immune reaction. By the design of the transfer matrix method and the preparation of the electrochemical etching method, the fluorescence peak wavelength of the quantum dots is located in the forbidden band of the Bragg mirror. The fluorescence of QDs are enhanced by PSi Bragg mirror. Egp38 antigen detection limit of 300fg/mL is achievable. Our results exhibit that the biosensor combining PSi Bragg mirror and QDs can potentially be applied to the clinical detection of hydatid disease.