A Highly Sensitive $\boldsymbol{O}_{2}{}^{\bullet-}$ Biosensor Based on PEDOT:PSS/SA Composite Conductive Hydrogel

Superoxide anion (O 2 ^·− ) plays a vital role in the pathogenesis of many diseases, making it a biomarker of great value in early assessment of disease progression. However, due its short half-life, low concentration and rapid fluctuations, detecting O 2 ^·− poses significant challenges. In this study, we proposed an electrochemical biosensor based on a composite conductive hydrogel that enabled rapid and sensitive O 2 ^·− detection. The hydrogel synthesized with poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDPT:PSS) and sodium alginate (SA) exhibited good conductivity and mechanical properties. When applied for O 2 ^·− detection, the composite conductive hydrogel-based biosensor showed a linear range of $0.011\sim 32.59\ \mu\mathrm{M}$ , a sensitivity of $9.383\ \mu\mathrm{A}\ \mu\mathrm{M}^{-1}\text{cm}^{-2}$ and a detection limit of $0.007\ \mu\mathrm{M}$ , with robust anti-interference capabilities and stability. This innovative O 2 ^·− biosensor achieved high responsiveness at low concentrations and held promise for advancing O 2 ^·− detection and facilitating early disease diagnosis.