Abstract The incidence of breast cancer has been increasing over the years. To control and monitor this disease several tumor biomarkers have been proposed for early diagnosis, patient follow-up and/or treatment guidance. The only serum breast cancer biomarker in current use is the cancer antigen 15-3 (CA 15-3). Highly sensitive and label-free detection of the biomarker carbohydrate antigen 15-3 (CA 15-3) remains a challenge in the diagnosis of breast cancer. Here, a novel electrochemical immunosensor capable of sensitive and label-free detection of CA 15-3 is reported. This unique immunosensor, equipped with a highly conductive nanocomposite (i.e., thiolated graphene quantum dots modified silver nanocubics (Ag NCs)-modified electrode, exhibited significantly increased electron transfer and high sensitivity towards CA 15-3. This novel immunosensor, with a limit of detection 0.019 U/mL, worked well over two linear range of 0.095–0.5 and 0.25–1 U/mL. Unlike conventional immunosensors, which usually involve complicated label processing and time consuming separations, the use of highly conductive graphene avoids the need for labels and is simple in nature. The strategy developed for this immunosensor provides a promising approach for clinical research and diagnostic applications.

中文翻译：

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在半胱胺覆盖的 GQDs 上使用逐层组装的具有多孔结构的银纳米立方体探索抗原抗体相互作用对腺癌细胞裂解物中癌症生物标志物的超灵敏识别

【摘要】：近年来,乳腺癌的发病率呈上升趋势。为了控制和监测这种疾病，已经提出了几种肿瘤生物标志物用于早期诊断、患者随访和/或治疗指导。目前使用的唯一血清乳腺癌生物标志物是癌抗原 15-3 (CA 15-3)。生物标志物碳水化合物抗原 15-3 (CA 15-3) 的高灵敏度和无标记检测仍然是乳腺癌诊断中的一个挑战。在这里，报道了一种能够灵敏且无标记地检测 CA 15-3 的新型电化学免疫传感器。这种独特的免疫传感器配备了高导电纳米复合材料（即硫醇化石墨烯量子点修饰的银纳米立方 (Ag NCs) 修饰电极），显示出显着增加的电子转移和对 CA 15-3 的高灵敏度。这种新型免疫传感器，检测限为 0.019 U/mL，在 0.095–0.5 和 0.25–1 U/mL 的两个线性范围内工作良好。与通常涉及复杂的标记处理和耗时的分离的传统免疫传感器不同，使用高导电石墨烯避免了对标记的需求，并且本质上很简单。为这种免疫传感器开发的策略为临床研究和诊断应用提供了一种有前途的方法。