1. A sensing platform for highly sensitive immunoassay based on metal-enhanced fluorescence of CdSe@ZnS.
- Author
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Chen, Fangfang, Li, Yihan, Ma, Ziwei, Li, Ning, Chen, Chunxia, Shen, Huaibin, Xu, Dangdang, Liu, Min, Yuan, Yufeng, and Li, Lin Song
- Subjects
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SURFACE plasmon resonance , *FLUORESCENCE , *WAVE functions , *ELECTRIC fields , *FINITE element method - Abstract
Insufficient sensitivity caused by low radiative intensity of employed fluorescent material is the main obstacle toward early accurate diagnosis of fatal diseases when applying fluorescence analysis. Herein, we have developed a dual amplification procedure to overcome this issue. We first synthesize high-quality CdSe@ZnS@SiO 2 core/shell quantum dots (QDs) with type-I band alignment to confine the carrier wave functions, thus ensuring high quantum yield (∼ 80%). The fluorescence intensity of those QDs is further amplified by localized surface plasmon resonance effect enabled by gold nanoparticles. We finally construct CdSe@ZnS@SiO 2 and Au@SiO 2 immune sandwich biosensor platform, and take C-reaction protein (CRP) as a test case. It is shown that this biosensor platform exhibits a wide detecting range between 0.5 and 100 ng/mL, and detecting limit of 0.076 ng/mL. We further apply this detecting scheme in serum and actual clinical, competing performance compared with the prevailing standard measurements in hospital has been obtained. Both experiment and the finite element analysis (FEA) approach calculation results indicate that a highly enhanced electric field between Au@SiO 2 and CdSe@ZnS@SiO 2 enhances the radiative recombination rates of the QDs@SiO 2 and decreases the fluorescence lifetime of that. The fluorescence intensity amplification scheme proposed herein is of great significance for the real-time and high-sensitivity early detection of biomarkers in the biomedicine. • Designing novel route of biological sensing via high-quality QDs-Gold system. • Highly enhanced electric field between Au@SiO 2 and QDs exists by Experiment and theoretical results. • By LSPR effect, the platform exhibits high sensitivity and wide detection range. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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