Herein, we synthesized high-performance SiO₂–core quantum dot (QD)–shell nanocomposites (SiO₂@PEI-QDs) using the polyethyleneimine (PEI)-mediated adsorption method. Cationic PEI was used to form a positively charged interlayer on the SiO₂ core, which achieved a dense adsorption of carboxylated QDs to form a shell of QDs and maintained a good dispersibility of the nanocomposite. The SiO₂@PEI-QDs showed excellent stability and high luminescence, and served as high-performance fluorescent labels for the detection of bacteria when used with the lateral flow immunoassay (LFA) technique. An SiO₂@PEI-QD-based LFA strip was successfully applied to rapidly detect Salmonella typhimurium in milk samples with a low limit of 5 × 10² cells per mL.

中文翻译：

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聚乙烯亚胺夹层二氧化硅核量子点壳纳米复合材料通过横向流动免疫分析灵敏检测鼠伤寒沙门氏菌

在此，我们使用聚乙烯亚胺 (PEI) 介导的吸附方法合成了高性能 SiO ₂ -核量子点 (QD)-壳纳米复合材料 (SiO _{2 @PEI-QDs)。阳离子PEI用于在SiO 2}核上形成带正电的夹层，实现了羧化QDs的密集吸附，形成QDs的壳，并保持了纳米复合材料的良好分散性。SiO ₂ @PEI-QDs 表现出优异的稳定性和高发光性，当与侧向流动免疫分析 (LFA) 技术一起使用时，可作为检测细菌的高性能荧光标记。基于 SiO ₂ @PEI-QD 的 LFA 试纸成功用于快速检测鼠伤寒沙门氏菌牛奶样品中的下限为 5 × 10 ^{2 个}细胞/mL。