São Carlos Institute of Physics, University of São Paulo , 13560-970 São Carlos, São Paulo, Brazil.
Departament of Materials Engineering, São Carlos School of Engineering, University of São Paulo , 13563-120 São Carlos, São Paulo, Brazil.
ACS Appl Mater Interfaces. 2017 Feb 22;9(7):5885-5890. doi: 10.1021/acsami.6b16105. Epub 2017 Feb 8.
Adsorption processes are responsible for detection of cancer biomarkers in biosensors (and immunosensors), which can be captured with various principles of detection. In this study, we used a biosensor made with nanostructured films of polypyrrole and p53 antibodies, and image analysis of scanning electron microscopy data made it possible to correlate morphological changes of the biosensor with the concentration of cells containing the cancer biomarker p53. The selectivity of the biosensor was proven by distinguishing images obtained with exposure of the biosensor to cells containing the biomarker from those acquired with cells that did not contain it. Detection was confirmed with cyclic voltammetry measurements, while the adsorption of the p53 biomarker was probed with polarization-modulated infrared reflection absorption (PM-IRRAS) and a quartz crystal microbalance (QCM). Adsorption is described using the Langmuir-Freundlich model, with saturation taking place at a concentration of 100 Ucells/mL. Taken together, our results point to novel ways to detect biomarkers or any type of analyte for which detection is based on adsorption as is the case of the majority of biosensors.
吸附过程负责在生物传感器（和免疫传感器）中检测癌症生物标志物，这些生物标志物可以通过各种检测原理进行捕获。在这项研究中，我们使用了一种由聚吡咯和 p53 抗体的纳米结构薄膜制成的生物传感器，并且通过扫描电子显微镜数据的图像分析，可以将生物传感器的形态变化与含有癌症生物标志物 p53 的细胞浓度相关联。通过区分生物传感器暴露于含有生物标志物的细胞获得的图像与未暴露于生物标志物的细胞获得的图像，证明了生物传感器的选择性。通过循环伏安法测量来确认检测，同时使用偏振调制红外反射吸收（PM-IRRAS）和石英晶体微天平（QCM）来探测 p53 生物标志物的吸附。吸附用 Langmuir-Freundlich 模型描述，在浓度为 100 Ucells/mL 时达到饱和。总之，我们的结果为检测生物标志物或任何类型的分析物提供了新的方法，因为大多数生物传感器都是基于吸附进行检测的。
