Conventional sandwich-type immunoassays are widely used for protein biomarker detection, yet their workflows are challenged by the need for multiple incubation steps separated by washing cycles. Conducting these immunoassays is thus rather time-consuming and labor-intensive. Moreover, the limited sensitivity around 0.1 ng mL⁻¹ is challenging the monitoring of cancer recurrence, for instance after radical prostatectomy in the case of prostate cancer. Here, we report a single-step homogeneous immunoassay using dual-color light scattering of metal nanoparticles. We detect human free prostate-specific antigen (f-PSA) in a buffered protein matrix solution with a single mixing and incubation step, no washing or purification cycle, and with a total experiment time of less than one hour. The limit of detection is 20 pg mL⁻¹, which is 5× lower as compared to a conventional ELISA kit for f-PSA. The simpler, faster and more sensitive detection of cancer biomarkers opens promising opportunities to improve cancer diagnosis and health monitoring after cancer treatment.

中文翻译：

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金属纳米粒子双色光散射的单步均相免疫分析法检测前列腺特异性抗原

常规的夹心型免疫测定法广泛用于蛋白质生物标志物的检测，但是其工作流程受到需要由洗涤周期分开的多个孵育步骤的挑战。因此进行这些免疫测定是相当耗时和劳动密集的。此外，灵敏度有限，约为0.1 ng mL ^-1例如在进行前列腺癌根治性前列腺切除术后，对癌症复发的监测正面临挑战。在这里，我们报告使用金属纳米颗粒的双色光散射进行单步均相免疫测定。我们只需一次混合和孵育步骤，无需清洗或纯化周期，并且总实验时间少于一小时，即可在缓冲的蛋白质基质溶液中检测人游离前列腺特异性抗原（f-PSA）。检测极限为20 pg mL ^-1，与用于f-PSA的常规ELISA试剂盒相比降低了5倍。癌症生物标志物的更简单，更快和更灵敏的检测为改善癌症治疗后的癌症诊断和健康监测提供了广阔的机遇。