Fabrication and Characterization of an Electrochemical Biosensor Based on DMSO Treated PEDOT:PSS-MWCNT- Chitosan Nanocomposite Modified ITO Electrode for Sarcosine Detection

In this work, a poly (3,4-ethylenedioxythioph- ene):poly (styrene sulfonate)–multiwalled carbon nanotube-Chitosan (PEDOT:PSS-MWCNT-CHIT) nanocomposite was prepared by solution mixing method and it acts as the biologically sensitive membrane of an electrochemical biosensor for the detection of the analyte sarcosine (SAR) and a potential biomarker for prostate cancer (PCa). The PEDOT:PSS-MWCNT-CHIT/sarcosine oxidase (SOx) modified tin-doped indium oxide (ITO) acts as the working electrode for the biosensor. It was observed that PEDOT:PSS forms
$\pi -\pi $
/hydrophobic linkage and ionic linkage with the MWCNT and Chitosan molecular chain. The electrode has been further post-treated with dimethyl sulphoxide (DMSO) solution to enhance the conductivity. It is found that DMSO treated PEDOT:PSS-MWCNT-CHIT electrode enhances some important characteristics better than existing devices as it showed a high sensitivity of
$3.02\times 10^{{6}}~\mu $
A mM
$^{-{1}}\text {(}{R}^{{2}} =0.9712$
), a low limit of detection (LOD) of 1.1 nM, a limit of quantification of 3.3 nM, and a high dynamic range of 0.89–
$123.846~\mu $
M. Other measurements conducted demonstrated the effectiveness of the device, as it exhibited higher electron transfer kinetics, good selectivity, and/or specificity and acceptable stability.