Preparation Of Core-shell Luminescent Nanoparticles And The Analytical Detection Of Cancer Markers

In recent years, upconversion nanoparticles(UCNPs) have more prominent in bioanalysis on account of their special luminescent properties compared with conventional luminescent materials. Such as narrow emission peak, high signal-to-noise ratio, less harmful to biological samples, good sample penetration depths, and so on. Based on this, we synthesized red NaYF4:Yb,Er/NaGdF4 and near-infrared NaYF4:Yb,Tm/NaGdF4 core-shell upconverting nanoparticles, then the upconverting nanoparticles were conjugated with special anti-AFP1(Ab1), and acted as the donor; At the same time, Gold nanorods(GNRs) with special longitudinal SPR band were synthesized, and acted as the acceptor. Based on luminescence energy transfer(LET), some new ways for detection and analysis of biological molecules(alpha fetoprotein) were developed.⑴ The stable red NaYF4:Yb,Er nanoparticles were obtained, next, the NaYF4:Yb,Er/NaGd F4 core-shell nanoparticles were synthesized by the cation exchange and conjugated with Ab1. At the same time, the products were characterized by transmission electron microscopy、?uorescence spectrophotometer. By using the quenching effect of GNRs to upconverting nanoparticles, the NaYF4:Yb,Er/Na GdF4-GNRs system was obtained. And because of the specificity recognition between antigen and antibody to detect AFP. the linear range was 0.089-22.88 ng/mL for AFP(R = 0.995), the detection limit as low as 0.083 ng/mL.⑵ The high luminescence efficiency near-infrared NaYF4:Yb,Tm/NaGdF4 core-shell nanoparticles were synthesized and conjugated with Ab1,and acted as energy donor. GNRs with positive charge as energy acceptor. Due to the electrostatic interaction between NaYF4:Yb,Tm/NaGdF4 core-shell nanoparticles and GNRs, the NaYF4:Yb,Tm/NaGdF4-GNRs LET system was established. When the AFP were added into the sample, due to the specificity recognition between antigen and antibody, the LET would be interrupted. So we set up a new method that “turn-on” NIR for the determination of AFP. the linear range was from 0.18 ng/mL to 11.44 ng/mL for AFP(R = 0.995), the detection limit was 0.16 ng/mL.⑶ Firstly, Ab1-NaYF4:Yb,Tm/NaGdF4 core-shell nanoparticles were obtained and acted as donor. At the same time, Ab2-GNRs with a high absorption band around 790 nm were acted as acceptor. Based on this, the sandwich-type “turn-off” LET could occur. Thereby this system could be used for detecting alpha fetoprotein(AFP). the linear range of detection was from 0.35 to 11.44 ng/mL for AFP(R = 0.995), with a detection limit was 0.28 ng/mL.