Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
ESA, Instituto Politécnico de Bragança, Campus Santa Apolónia, Apartado 1172, 5301-855 Bragança, Portugal; CQ-VR, Centro de Química - Vila Real, University of Trás-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal.
Biosens Bioelectron. 2015 Sep 15;71:332-341. doi: 10.1016/j.bios.2015.04.050. Epub 2015 Apr 20.
Electrochemical aptasensors may be used to detect protein biomarkers related to tumor activity. Osteopontin (OPN), a protein present in several body fluids, has been suggested as a potential biomarker since its overexpression seems to be associated with breast cancer progression and metastasis. In this work, a simple and label-free voltammetric aptasensor for the detection of OPN, using an RNA aptamer previously reported to have affinity for human OPN as the molecular recognition element, and the ferro/ferricyanide solution as a redox probe, was developed. The RNA aptamer was synthetized and immobilized in a working microelectrode gold surface (diameter of 0.8mm) of a screen-printed strip with a silver pseudo-reference electrode and a gold counter electrode. The electrochemical behavior of the electrode surface after each preparation step of the aptasensor was studied using cyclic voltammetry and square wave voltammetry. The resulting voltammetric aptasensor was used to detect OPN in standard solutions. Cyclic voltammetry results showed that the aptasensor has reasonable detection and quantification limits (3.7 ± 0.6 nM and 11 ± 2 nM, respectively). Indeed, the detection limit falls within the osteopontin levels reported in the literature for patients with metastatic breast cancer. Moreover, the aptasensor is able to selectively detect the target protein in the presence of other interfering proteins, except for thrombin. Considering the overall results, a possible application of the aptasensor for cancer prognosis may be foreseen in a near future.
电化学适体传感器可用于检测与肿瘤活性相关的蛋白质生物标志物。骨桥蛋白(OPN)是一种存在于多种体液中的蛋白质,由于其过表达似乎与乳腺癌的进展和转移有关,因此被认为是一种潜在的生物标志物。在这项工作中,开发了一种简单且无标记的伏安适体传感器,用于检测 OPN,使用先前报道的与人 OPN 具有亲和力的 RNA 适体作为分子识别元件,以及铁氰化亚铁溶液作为氧化还原探针。RNA 适体被合成并固定在带有银伪参比电极和金对电极的丝网印刷条的工作微电极金表面(直径 0.8mm)上。使用循环伏安法和方波伏安法研究了适体传感器的每个制备步骤后电极表面的电化学行为。所得伏安适体传感器用于检测标准溶液中的 OPN。循环伏安法结果表明,该适体传感器具有合理的检测限和定量限(分别为 3.7 ± 0.6 nM 和 11 ± 2 nM)。实际上,检测限落在文献中报道的转移性乳腺癌患者的骨桥蛋白水平内。此外,该适体传感器能够在存在其他干扰蛋白(除了凝血酶)的情况下选择性地检测靶蛋白。考虑到整体结果,在不久的将来可能可以预见该适体传感器在癌症预后中的潜在应用。