适配体结合聚酰胺-胺修饰的磁性纳米粒子富集单增李斯特菌

Enrichment of Listeria monocytogenes by aptamer-conjugated polyamide-amine polymer-magnetic nanoparticles

目的制备聚酰胺-胺聚合物修饰的磁性纳米粒子,增加连接适配体的数量,提高富集单增李斯特菌的效率。方法通过迈克尔加成和酰胺化的级联反应,在Fe3O4磁性纳米粒子表面接枝3.0代聚酰胺-胺树枝状聚合物(poly(amidoamine)dendrimers,PAMAM),制得聚酰胺-胺磁性纳米粒子(G3-MNPs),并对其进行表征。G3-MNPs偶联生物素标记的单增李斯特菌特异性适配体,获得适配体磁性纳米粒子(AP-G3-MNPs)。然后对AP-G3-MNPs富集单增李斯特菌的工作条件和捕获率进行测定。结果傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)分析、Zeta电位测定以及碳、氮元素分析结果表明,PAMAM已接枝在MNPs表面,G3-MNPs偶联适配体的效率为1.412 nmol/mg。AP-G3-MNPs(200μg)对浓度为2×10^2~2×10^8 CFU/mL的单增李斯特菌的捕获率均大于90%。结论接枝PAMAM提高了MNPs的负载能力,增强了其富集单增李斯特菌的能力。

Objective To prepare magnetic nanoparticles modified by polyamide-amine polymer to increase the number of joint aptamers and improve the efficiency of enrichment of Listeria monocytogenes.Methods The surface of Fe3 O4 magnetic nanoparticles were grafted with three gaps of poly(amidoamine)dendrimers(PAMAM)(G3-MNPs)by michael addition and amidation cascade reaction.Then G3-MNPs were characterized.G3-MNPs were conjugated with biotined aptamers against L.monocytogenes to get AP-G3-MNPs.The enrichment conditions of AP-G3-MNPs and capture efficiency for L.monocytogenes were determined.Results PAMAM was successfully grafted on MNPs based on FT-IR spectra,zeta potential determination and element analysis of carbon and nitrogen.The loading rate of G3-MNPs for biotined aptamers was 1.412 nmol/mg.The specific capture rate of AP-G3-MNPs(200μg)was higher than 90%for Listeria monocytogenes with concentration of 2×10^2-2×10^8 CFU/mL.Conclusion Grafting PAMAM on MNPs increased its loading rate for aptamers and the capture efficiency for L.monocytogenes.