The integration of nanomaterials in the field of (bio)sensors has allowed developing strategies with improved analytical performance. In this work, ultrasmall core-shell Fe₃O₄@Au magnetic nanoparticles (MNPs) were used as the platform for the immobilization of event-specific Roundup Ready (RR) soybean and taxon-specific DNA sequences. Firstly, monodisperse Fe₃O₄ MNPs were synthesized by thermal decomposition and subsequently coated with a gold shell through reduction of Au(III) precursor on the surface of the MNPs in the presence of an organic capping agent. This nanosupport exhibited high colloidal stability, average particle size of 10.2 ± 1.3 nm, and spherical shape. The covalent immobilization of ssDNA probe onto the Au shell of the Fe₃O₄@Au MNPs was achieved through a self-assembled monolayer (SAM) created from mixtures of alkane thiols (6-mercapto-1-hexanol and mercaptohexanoic acid). The influence of the thiols ratio on the electrochemical performance of the resulting electrochemical genoassays was studied, and remarkably, the best analytical performance was achieved for a pure mercaptohexanoic acid SAM. Two quantification assays were designed; one targeting an RR sequence and a second targeting a reference soybean gene, both with a sandwich format for hybridization, signaling probes labelled with fluorescein isothiocyanate (FITC), enzymatic amplification and chronoamperometric detection at screen-printed carbon electrodes (SPCE). The magnetogenoassays exhibited linear ranges from 0.1 to 10.0 nM and from 0.1 to 5.0 nM with similar detection limits of 0.02 nM and 0.05 nM for the event-specific (RR) and the taxon-specific (lectin) targets, respectively. The usefulness of the approach was demonstrated by its application to detect genetically modified organisms (GMOs) in feed and food.

纳米材料在（生物）传感器领域的整合使得能够开发具有改进分析性能的策略。在这项工作中，超小核壳 Fe ₃ O ₄ @Au 磁性纳米颗粒 (MNP) 被用作固定事件特异性农达就绪 (RR) 大豆和分类单元特异性 DNA 序列的平台。首先，通过热分解合成单分散Fe ₃ O ₄ MNP，然后在有机封端剂存在下通过还原Au(III)前体在MNP表面涂覆金壳。该纳米载体表现出高胶体稳定性，平均粒径为10.2±1.3 nm，呈球形。 ssDNA 探针共价固定在 Fe ₃ O ₄ @Au MNP 的 Au 壳上是通过由烷硫醇（6-巯基-1-己醇和巯基己酸）混合物产生的自组装单层（SAM）实现的。研究了硫醇比例对所得电化学分析的电化学性能的影响，值得注意的是，纯巯基己酸 SAM 实现了最佳分析性能。设计了两种定量测定；一个针对 RR 序列，第二个针对参考大豆基因，两者均采用夹心形式进行杂交、用异硫氰酸荧光素 (FITC) 标记的信号探针、酶促扩增和丝网印刷碳电极 (SPCE) 上的计时电流检测。磁发生测定的线性范围为 0.1 至 10.0 nM 和 0.1 至 5.0 nM，事件特异性 (RR) 和分类单元特异性（凝集素）靶标的相似检测限分别为 0.02 nM 和 0.05 nM。 该方法在检测饲料和食品中转基因生物 (GMO) 方面的应用证明了该方法的实用性。