Yaiwong Patrawadee, Anuthum Siriporn, Sangthong Padchanee, Jakmunee Jaroon, Bamrungsap Suwussa, Ounnunkad Kontad
Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
The Graduate School, Chiang Mai University, Chiang Mai, Thailand.
Front Bioeng Biotechnol. 2023 May 22;11:1182880. doi: 10.3389/fbioe.2023.1182880. eCollection 2023.
The quantification of alpha-fetoprotein (AFP) as a potential liver cancer biomarker which is generally found in ultratrace level is of significance in biomedical diagnostics. Therefore, it is challenging to find a strategy to fabricate a highly sensitive electrochemical device towards AFP detection through electrode modification for signal generation and amplification. This work shows the construction of a simple, reliable, highly sensitive, and label-free aptasensor based on polyethyleneimine-coated gold nanoparticles (PEI-AuNPs). A disposable ItalSens screen-printed electrode (SPE) is employed for fabricating the sensor by successive modifying with PEI-AuNPs, aptamer, bovine serum albumin (BSA), and toluidine blue (TB), respectively. The AFP assay is easily performed when the electrode is inserted into a small Sensit/Smart potentiostat connected to a smartphone. The readout signal of the aptasensor derives from the electrochemical response of TB intercalating into the aptamer-modified electrode after binding with the target. The decrease in current response of the proposed sensor is proportional to the AFP concentration due to the restriction of the electron transfer pathway of TB by a number of insulating AFP/aptamer complexes on the electrode surface. PEI-AuNPs improve SPE's reactivity and provide a large surface area for aptamer immobilization whereas aptamer provides selectivity to the target AFP. Consequently, this electrochemical biosensor is highly sensitive and selective for AFP analysis. The developed assay reveals a linear range of detection from 10 to 50000 pg mL with = 0.9977 and provided a limit of detection (LOD) of 9.5 pg mL in human serum. With its simplicity and robustness, it is anticipated that this electrochemical-based aptasensor will be a benefit for the clinical diagnosis of liver cancer and further developed for other biomarkers analysis.
甲胎蛋白（AFP）作为一种潜在的肝癌生物标志物，通常以超痕量水平存在，其定量在生物医学诊断中具有重要意义。因此，通过电极修饰来产生和放大信号，寻找一种构建用于AFP检测的高灵敏度电化学装置的策略具有挑战性。这项工作展示了一种基于聚乙烯亚胺包覆金纳米颗粒（PEI-AuNPs）的简单、可靠、高灵敏度且无标记的适体传感器的构建。使用一次性的ItalSens丝网印刷电极（SPE），通过依次用PEI-AuNPs、适体、牛血清白蛋白（BSA）和甲苯胺蓝（TB）修饰来制备传感器。当将电极插入连接到智能手机的小型Sensit/Smart恒电位仪中时，AFP检测很容易进行。适体传感器的读出信号源自TB与靶标结合后插入适体修饰电极的电化学响应。由于电极表面大量绝缘的AFP/适体复合物对TB电子转移途径的限制，所提出传感器的电流响应降低与AFP浓度成正比。PEI-AuNPs提高了SPE的反应活性，并为适体固定提供了大表面积，而适体为靶标AFP提供了选择性。因此，这种电化学生物传感器对AFP分析具有高灵敏度和选择性。所开发的检测方法显示检测线性范围为10至50000 pg/mL，R² = 0.9977，在人血清中的检测限（LOD）为9.5 pg/mL。凭借其简单性和稳健性，预计这种基于电化学的适体传感器将有利于肝癌的临床诊断，并进一步开发用于其他生物标志物分析。
