Department of Chemistry, Faculty of Science, Ege University, Bornova, 35100, Izmir, Turkey.
Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, Urla, 35430, İzmir, Turkey.
Anal Bioanal Chem. 2024 Nov;416(28):6421-6435. doi: 10.1007/s00216-024-05529-w. Epub 2024 Oct 1.
In this study, a novel aptasensor based on a transition metal oxide-modified pencil graphite electrode (PGE) was developed for the diagnosis of early-stage prostate cancer (PCa) via monitoring the prostate-specific antigen (PSA), which is the main biomarker for PCa. Single-use PGEs modified with pulsed deposited manganese oxide (MnOx) film were used to attach the amino-terminated aptamer specific to the PSA via carbodiimide chemistry. The designed aptasensor was placed in an electrochemical cell containing ferri/ferrocyanide ions as a redox probe to measure the charge transfer resistances (R) of the electrode surface by electrochemical impedance spectroscopy (EIS) to follow the response of each modification step. The effect of the medium pH on the ionic structure of the aptamer molecule according to its pI value and, thus, the reversing of the direction of the response (ΔR) by the pH change was also discussed. The level of PSA secreted from PCa cells was investigated using impedimetric transduction. The specificity of the aptasensor was validated through selectivity studies against non-specific tumor markers like VEGF and different cancer cell lines including breast cancer and androgen-insensitive prostate cancer. The developed system showcases a label-free, fast, specific, and cost-effective approach for PSA detection, highlighting the importance of medium pH and the electrostatic environment on the aptamer's response. Our work emphasizes the potential for such aptasensors in clinical diagnostics and paves the way for further exploration into using transition metal oxides in biosensing applications.
在这项研究中，开发了一种基于过渡金属氧化物修饰的铅笔石墨电极（PGE）的新型适体传感器，通过监测前列腺特异性抗原（PSA）来诊断早期前列腺癌（PCa），PSA 是 PCa 的主要生物标志物。使用脉冲沉积的氧化锰（MnOx）薄膜修饰一次性 PGE，通过碳二亚胺化学将末端为氨基的针对 PSA 的适体附着在电极表面。设计的适体传感器被放置在含有铁氰化铁/亚铁氰化铁离子的电化学电池中，作为氧化还原探针，通过电化学阻抗谱（EIS）测量电极表面的电荷转移电阻（R），以跟踪每个修饰步骤的响应。根据适体分子的等电点（pI），讨论了介质 pH 对适体分子离子结构的影响，以及 pH 变化导致响应方向反转（ΔR）的情况。通过阻抗转换研究了来自 PCa 细胞分泌的 PSA 水平。通过对非特异性肿瘤标志物如 VEGF 和不同的癌细胞系（包括乳腺癌和雄激素不敏感前列腺癌）的选择性研究验证了适体传感器的特异性。所开发的系统展示了一种无标记、快速、特异性和具有成本效益的 PSA 检测方法，强调了介质 pH 和适体静电环境对其响应的重要性。我们的工作强调了这种适体传感器在临床诊断中的潜力，并为进一步探索过渡金属氧化物在生物传感应用中的应用铺平了道路。
