Fabrication of refreshable aptasensor based on hydrophobic screen-printed carbon electrode interface

• Published in: The Science of the total environment 2020-04, Vol.712, p.136410-136410, Article 136410
• Main Authors: Fu, Jiayun, Dong, Haowei, Zhao, Qingxue, Cheng, Shuting, Guo, Yemin, Sun, Xia
• Format: Article
• Language: English
• Subjects: Graphene oxide-ferroferric oxide; Hydrophobic electrode; Magnetic catcher; Organophosphorus pesticides residues; Refreshable aptasensor
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.136410

In order to solve the problem that the sensor cannot be reused due to the passivation of the electrode surface, a refreshable electrochemical aptasensor based on a hydrophobic electrode and a magnetic nanocomposite had been developed. Therein, the hydrophobic electrode was formed by modifying a screen-printed carbon electrode (SPCE) with polydimethylsiloxane (PDMS), which could avoid adsorption of molecules on the electrode surface due to its hydrophobicity. Combined with aptamer (Apt), the synthesized graphene oxide-ferroferric oxide (GO-Fe3O4) was used as a magnetic catcher to capture specific organophosphorus pesticides (OPs), which could be removed to the working area of SPCE with a magnet for electrochemical detection. The performance analysis of hydrophobic electrode showed that the SPCE could be used twice. When the electrochemical signals of Apt/GO-Fe3O4 and OPs/Apt/GO-Fe3O4 were recorded using the same SPCE, the current differences between them were directly related to the concentrations of OPs. Through the contrast test between the spiked vegetable samples and the OPs standard solutions, it was found that the OPs concentrations could be qualitatively evaluated by comparing the current differences. At the same time, the characteristic of collecting target with magnetic catcher was helpful for detecting OPs with a low concentration. Therefore, the refreshable aptasensor provided a huge potential to small molecule target evaluation. [Display omitted] •The nanocomposite of GO-Fe3O4 and aptamer is used as magnetic catcher.•A hydrophobic electrode combined with a magnetic catcher to fabricate a renewable biosensor•The aptasensor can be used to evaluate OPs qualitatively.