Díaz-Martínez Inés, Miranda-Castro Rebeca, de-Los-Santos-Álvarez Noemí, Lobo-Castañón María Jesús
Departamento de Química Física y Analítica. Universidad de Oviedo, Av. Julián Clavería 8, 33006 Oviedo, Spain.
Instituto de Investigación Sanitaria del Principado de Asturias, Av. de Roma, 33011 Oviedo, Spain.
Anal Chem. 2024 Feb 8;96(7):2759-63. doi: 10.1021/acs.analchem.3c05891.
The shortage of specific glycan recognition reagents has proven a significant hurdle in the development of assays to detect altered glycoforms associated with cancer. Here, a carbohydrate-binding aptamer originally selected against the glycan moiety of prostate-specific antigen (PSA) is used as a lectin-mimicking reagent. As a first proof-of-principle, this aptamer has been applied to develop a sandwich-type electrochemical biosensor for the detection of the serum amyloid P (SAP) component, a glycosylated protein whose increased sialylation has been associated with pancreatic cancer. The assay combines a specific antibody for this potential tumor biomarker and the aptamer as capture and detection receptors, respectively. Two oriented antibody immobilization approaches, protein A-based and boronic ester-based attachment to self-assembled monolayers built onto gold surfaces, were comparatively evaluated, the latter being able to circumvent the unwanted interaction between the aptamer and the glycans on the electrode-attached antibody. The resulting biosensing platform allows the detection of the SAP glycoprotein at levels of nanograms per milliliter with a reproducibility value lower than 20%, both in aqueous buffer and in serum. This work represents a proof-of-concept of a promiscuous ligand of proteins with high levels of sialylated glycans typically produced by cancer cells.
事实证明，特异性聚糖识别试剂的短缺是开发检测与癌症相关的糖型改变的检测方法的一个重大障碍。在此，一种最初针对前列腺特异性抗原（PSA）的聚糖部分筛选出的碳水化合物结合适体被用作模拟凝集素的试剂。作为第一个原理验证，这种适体已被应用于开发一种夹心型电化学生物传感器，用于检测血清淀粉样蛋白P（SAP）成分，这是一种糖基化蛋白，其唾液酸化增加与胰腺癌有关。该检测方法分别结合了针对这种潜在肿瘤生物标志物的特异性抗体和适体作为捕获和检测受体。对两种定向抗体固定方法进行了比较评估，即基于蛋白A和基于硼酸酯的附着到金表面构建的自组装单层膜上，后者能够规避适体与电极附着抗体上的聚糖之间的不必要相互作用。所得的生物传感平台能够在水缓冲液和血清中检测纳克每毫升水平的SAP糖蛋白，重现性值低于20%。这项工作代表了一种针对癌细胞通常产生的高唾液酸化聚糖水平的蛋白质的混杂配体的概念验证。
