A polyaniline-modified immunosensor for E.coli O157:H7 detection based on electrical parameters and support vector regression

A immunochromatographic test strip was developed for the E.coli O157:H7 quantitative detection by integrating of electrochemical impedance technology and the support vector regression (SVR) model. The E.coli O157:H7 antibody was modified by the water-soluble polyaniline to accelerate the electron transfer rate and improved the electrochemical properties of the immunosensor. After the immune reaction, the bacteria were captured on the capture pad and formed the sandwich immune complex of “polyaniline-antibody-antigen-antibody”, which changed the conductivity of the capture pad. Electrochemical impedance spectroscopy (EIS) was used to characterize the immune reaction. An equivalent circuit for the immunochromatography test strip was established to simulate the performance of the immunosensor and its feasibility was verified. Seven electrical parameters, which were extracted by ZVIEW software,
$R_{S},\ R_{m},\ C_{m},\ R_{P}, CPE_{\mathrm{d}-\mathrm{T}},\ CPE_{\mathrm{d}-\mathrm{P}}$
, and
$C_{\text{stray}}$
, were input to build a quantitative detection model using the SVR method. The results showed that predicated the E.coli O157:H7 by the SVR model with regression correlation coefficient were 0.9512 for the calibration set and 0.9112 for the validation set. Therefore, it is feasible to establish a quantitative prediction method for E.coli O157:H7 using impedance electrical parameters and the support vector regression technology.