2020/07/08 by Matías Regiart, Alba Marina Gimenez, Alexandre T. Lopes +3 · 8 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · #Advanced biosensing and bioanalysis techniques #Amperometry #Analytical Chemistry (journal) #Catalysis #Chemistry #Chromatography #Colloidal gold #Detection limit #Electrochemical Analysis and Applications #Electrochemical sensors and biosensors #Electrochemistry #Electrode #Horseradish peroxidase #Materials science #Microfluidics #Nanoparticle #Nanoporous #Nanotechnology #Organic chemistry #Selectivity
paper · doi:10.1016/j.aca.2020.06.037
openalex publication_date 2020/07/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
An ultrasensitive and portable microfluidic electrochemical immunosensor for SOX-2 cancer biomarker determination was developed. The selectivity and sensitivity of the sensor were improved by modifying the microfluidic channel. This was accomplished through a physical-chemical treatment to produce a hydrophilic surface, with an increased surface to volume/ratio, where the anti-SOX-2 antibodies can be covalently immobilized. A sputtered gold electrode was used as detector and its surface was activated by using a dynamic hydrogen bubble template method. As a result, a gold nanoporous structure (NPAu) with outstanding properties, like high specific surface area, large pore volume, uniform nanostructure, good conductivity, and excellent electrochemical activity was obtained. SOX-2 present in the sample was bound to the anti-SOX-2 immobilized in the microfluidic channel, and then was labeled with a second antibody marked with horseradish peroxidase (HRP-anti-SOX-2) like a sandwich immunoassay. Finally, an H2O2 + catechol solution was added, and the enzymatic product (quinone) was reduced on the NPAu electrode at +0.1 V (vs. Ag). The current obtained was directly proportional to the SOX-2 concentration in the sample. The detection limit achieved was 30 pg mL−1, and the coefficient of variation was less than 4.75%. Therefore, the microfluidic electrochemical immunosensor is a suitable clinical device for in situ SOX-2 determination in real samples.