Smartphone-based electrochemical system with multi-walled carbon nanotubes/thionine/gold nanoparticles modified screen-printed immunosensor for cancer antigen 125 detection

In the paper, a smartphone-based electrochemical system with differential pulse voltammetry (DPV) measurement was developed for cancer antigen 125 (CA125) detection. The system was composed of screen-printed immunosensor, miniaturized electrochemical detector and Android smartphone. Combined with multi-walled carbon nanotubes (MWCNTs)/ thionine (Thi)/ gold nanoparticles (AuNPs) modified screen-printed immunosensor, miniaturized electrochemical detector realized high accuracy detection of CA125. The datum were transmitted to Android smartphone through Bluetooth. The detector was powered by audio jack of smartphone, which also used 3.3 V button cell and USB as additional power supply. Android application (APP) running on a smartphone served to control detection process and show detection results. The experimental results indicated that there had good linear relationship between DPV peak currents and the logarithm of CA125 concentrations in the range from 1.3 U mL−1 to 260 U mL−1. The limit of detection (LOD) was 2 mU mL−1. The smartphone-based electrochemical system was also evaluated for the analysis of human serum sample. The detection results showed good agreement with the Roche electrochemical luminescence immunoassay (ECLIA) tests. The proposed system provided a new method for tumor marker detection in remote medicine centre or developing area.