Analytical Sciences

Polyelectrolyte-protected Dual-color-quantum-dot Assembled Silica Nanoparticles and Their Application in Simultaneous Fluorescence Determination of e Antigen and Surface Antigen of Hepatitis B

Xue-Ping CAI,* Bin ZHANG,*,** Xiao-Bo CHEN,* Hai-Yang DING,* Bing-Ren GU,** and Hong-Ping XIE*

*College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China
**Suzhou Institute for Drug Control, Suzhou 215104, China

Cationic poly-diallyldimethylammonium (PDADMAC), green CdTe quantum dots (QDs) or red CdS coated CdTe QDs, and anionic polyacrylic acid (PAA) were respectively assembled on the nano-carrier SiO₂ to prepare green fluorescence composite nanoparticles (GF-QDs) and red ones (RF-QDs) with the structure SiO₂/PDADMAC/QD/PDADMAC/PAA. The sandwich structure “PDADMAC/QD/PDADMAC” on the nano-carrier not only realized the protection to fluorescence of QDs but also avoided the fluorescence shielding of silica shell for the assembled QDs. In 7 days, the diluent solutions of GF-QD and RF-QD all have a very stable fluorescence. On the contrary, the fluorescence of diluent solutions of red and green QDs reduced by 75.99 and 94.35%, respectively. Indeed, they have not fluorescent shielding and have a very slight fluorescent enhancement. Based on GF-QD and RF-QD, the simultaneous determination of Hepatitis B e antigen and surface antigen has been established. Their determination in buffer and plasma all showed good precision and accuracy.

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