AUTHOR=Chanarsa Supakeit , Jakmunee Jaroon , Ounnunkad Kontad 

TITLE=A sandwich-like configuration with a signal amplification strategy using a methylene blue/aptamer complex on a heterojunction 2D MoSe2/2D WSe2 electrode: Toward a portable and sensitive electrochemical alpha-fetoprotein immunoassay

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.916357

DOI=10.3389/fcimb.2022.916357

ISSN=2235-2988

ABSTRACT=Liver cancer is one of the most global health problems that features a high mortality rate. Alpha-fetoprotein (AFP) is a potential liver cancer biomarker for the diagnosis of liver cancer. The quantitative detection of AFP at an ultratrace level has important medical significance. Using reaction of antibody-antigen pair in immunosensor enables the sensitive and selective AFP assay. Finding strategy in signal generation and amplification is challenging to fabricate new sensitive electrochemical immunosensor for the AFP detection. This study demonstrates the construction of simple, reliable, and label-free immunosensor for detection of AFP on a smart phone. Exfoliated two-dimensional (2D) MoSe2 and 2D WSe2 were employed to modify the disposable screen-printed carbon electrode (SPCE) for use as the electrochemical platform, which is affixed to small potentiostat connected on a smart phone. The modified electrode offers the antibody immobilization and allows the detection of AFP via immunocomplex forming sandwich-like configuration with AFP-corresponding aptamer. A heterojunction 2D MoSe2/2D WSe2 composite improves SPCE’s reactivity and provides a large surface area and good adsorption capacity for the immobilizing antibodies. The signal generation for the immunosensor is from the electrochemical response of MB intercalating into the aptamer bound on the electrode. The response for the proposed sandwich-like immunosensor is proportional to the AFP concentration (1.0-50000 pg mL-1). The biosensor has a potential for the development of a simple and robust point-of-care diagnostic platform for the clinical diagnosis of liver cancer, achieving a low limit of detection (0.85 pg mL-1), high sensitivity, high selectivity, good stability and excellent reproducibility.