The overexpression of folate receptors on cell surfaces is associated with abnormalities linked to epithelial cancers. This study reports on a capacitive biosensor that employs folic acid as a recognition molecule for the biosensing of folate receptors. The biosensor is composed of a thin film of Ti–W oxides conjugated with folic acid that serves as a working electrode in a three-electrode electrochemical cell configuration. The thin film of Ti–W oxides, featuring a mixture of TiO anatase and rutile phases, was fabricated using the pulsed laser deposition method and subsequently functionalized with folic acid. Characterization of the thin film before and after functionalization was conducted using AFM, XPS, and contact angle measurements. The functionalization study confirmed a stable bond between folic acid and the surface of the thin film. The interaction between the functionalized transducer and the folate receptor was investigated by determining the electrochemical capacitance using an electrochemical capacitance spectroscopy setup. Folate receptor recognition assays demonstrated that the biosensor response signal, or chemical hardness (in terms of electrochemical capacitance), is selective and directly proportional to the folate receptor concentration, with a limit of detection of 200 pM (0.2 nM). These findings are promising for the application of this detector in the recognition of folate receptors, particularly for point-of-care analysis.

中文翻译：

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基于叶酸固定化[式略]氧化物薄膜的叶酸受体检测

细胞表面叶酸受体的过度表达与上皮癌相关的异常有关。这项研究报告了一种电容式生物传感器，该传感器采用叶酸作为叶酸受体生物传感的识别分子。该生物传感器由与叶酸结合的 Ti-W 氧化物薄膜组成，在三电极电化学电池配置中充当工作电极。 Ti-W 氧化物薄膜采用 TiO2 锐钛矿相和金红石相的混合物，采用脉冲激光沉积方法制备，随后用叶酸进行功能化。使用 AFM、XPS 和接触角测量对功能化前后的薄膜进行表征。功能化研究证实了叶酸和薄膜表面之间存在稳定的键合。通过使用电化学电容光谱装置测定电化学电容来研究功能化传感器和叶酸受体之间的相互作用。叶酸受体识别测定表明，生物传感器响应信号或化学硬度（就电化学电容而言）具有选择性，并且与叶酸受体浓度成正比，检测限为 200 pM (0.2 nM)。这些发现对于该检测器在叶酸受体识别中的应用很有希望，特别是对于即时分析。