A new portable toluidine blue/aptamer complex-on-polyethyleneimine-coated gold nanoparticles-based sensor for label-free electrochemical detection of alpha-fetoprotein

Patrawadee Yaiwong; Siriporn Anuthum; Padchanee Sangthong; Jaroon Jakmunee; Suwussa Bamrungsap; Kontad Ounnunkad

doi:10.3389/fbioe.2023.1182880

A new portable toluidine blue/aptamer complex-on-polyethyleneimine-coated gold nanoparticles-based sensor for label-free electrochemical detection of alpha-fetoprotein

Front Bioeng Biotechnol. 2023 May 22:11:1182880. doi: 10.3389/fbioe.2023.1182880. eCollection 2023.

Authors

Patrawadee Yaiwong^{1

2}, Siriporn Anuthum^{1

2}, Padchanee Sangthong¹, Jaroon Jakmunee¹, Suwussa Bamrungsap³, Kontad Ounnunkad¹

Affiliations

¹ Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
² The Graduate School, Chiang Mai University, Chiang Mai, Thailand.
³ National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand.

Abstract

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^-1 with R ² = 0.9977 and provided a limit of detection (LOD) of 9.5 pg mL^-1 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.

Keywords: alpha-fetoprotein; aptasensor; detection; electrochemical biosensor; gold nanoparticles (AuNPs); screen-printed electrode (SPE).

Grants and funding

This research project was supported by Fundamental Fund 2023, Chiang Mai University.