Sarcosine is a recently identified biomarker for prostate cancer. However, the rapid detection methods for sarcosine are relatively lack because of the low concentration and the presence of complicated interfering substances in serum or urine. In this manuscript, hollow nanospheres of Fe3O4 was synthesized and used as carrier to disperse Pt (Pt) nanoparticles. In order to achieve excellent electron transfer ability, we use polyaniline to coat Pt-Fe3O4 nanoparticles, and pyrolyze the polyaniline to carbon (C). Thus, hollow magnetic Pt-Fe3O4@C nanocomposites with good electron transfer ability are formed. The Pt-Fe3O4@C nanocomposites have high catalytic activity and stability. The nanocomposites were immobilized on glassy carbon electrode (GCE) to construct a nonenzyme hydrogen peroxide (H2O2) sensor (Pt-Fe3O4@C/GCE). We further construct a sensitive sarcosine biosensor by immobilizing sarcosine oxidase (SOx) on the Pt-Fe3O4@C/GCE. The high catalytic activity and good biocompatibility of Pt-Fe3O4@C nanocomposites greatly retained the bioactivity of immobilized SOx, and the prepared sarcosine biosensor has good electrocatalytic performance towards sarcosine. It has a linear detection range between 0.5 and 60 μM with a limit of detection (LOD) of 0.43 μM (the signal to noise ratio is 3), and the sensitivity is 3.45 nA μM-1 (48.8 nA μM-1 cm-2), which has the potential to be used for rapid screening of prostate cancer.

中文翻译：

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基于中空磁性 Pt-Fe3O4@C 纳米球的电流型肌氨酸生物传感器

肌氨酸是最近发现的前列腺癌生物标志物。但由于肌氨酸浓度低，血清或尿液中存在复杂的干扰物质，目前对肌氨酸的快速检测方法相对缺乏。在这份手稿中，合成了空心的 Fe3O4 纳米球，并将其用作载体来分散 Pt (Pt) 纳米颗粒。为了获得优异的电子转移能力，我们使用聚苯胺包覆 Pt-Fe3O4 纳米颗粒，并将聚苯胺热解为碳 (C)。因此，形成了具有良好电子转移能力的中空磁性 Pt-Fe3O4@C 纳米复合材料。Pt-Fe3O4@C纳米复合材料具有较高的催化活性和稳定性。将纳米复合材料固定在玻璃碳电极（GCE）上以构建非酶过氧化氢（H2O2）传感器（Pt-Fe3O4@C/GCE）。我们通过将肌氨酸氧化酶 (SOx) 固定在 Pt-Fe3O4@C/GCE 上进一步构建了一种灵敏的肌氨酸生物传感器。Pt-Fe3O4@C纳米复合材料的高催化活性和良好的生物相容性极大地保留了固定化SOx的生物活性，制备的肌氨酸生物传感器对肌氨酸具有良好的电催化性能。它的线性检测范围在 0.5 到 60 μM 之间，检测限 (LOD) 为 0.43 μM（信噪比为 3），灵敏度为 3.45 nA μM-1（48.8 nA μM-1 cm-2 )，它有可能用于前列腺癌的快速筛查。制备的肌氨酸生物传感器对肌氨酸具有良好的电催化性能。它的线性检测范围在 0.5 到 60 μM 之间，检测限 (LOD) 为 0.43 μM（信噪比为 3），灵敏度为 3.45 nA μM-1（48.8 nA μM-1 cm-2 )，它有可能用于前列腺癌的快速筛查。制备的肌氨酸生物传感器对肌氨酸具有良好的电催化性能。它的线性检测范围在 0.5 到 60 μM 之间，检测限 (LOD) 为 0.43 μM（信噪比为 3），灵敏度为 3.45 nA μM-1（48.8 nA μM-1 cm-2 )，它有可能用于前列腺癌的快速筛查。