Impact of protein fouling on electrochemistry of hyaluronic acid/curcumin/carbon nanotubes modified electrode: Toward electrochemical measurement of dopamine

Dopamine detection and concentration identification using electrochemical sensing technique is critically important for a wide range of disease diagnosis and monitoring. However, the sensitivity of electrochemical sensing can be significantly affected from the non-specific protein adsorption in biological fluid samples. In this study, we aim to creating a modified electrode with excellent resistance to protein fouling. Herein, we have developed an antifouling electrochemical dopamine sensing interface integrated hydrophilicity hyaluronic acid (HA) with curcumin/multi-walled carbon nanotubes (CM/MWCNTs) via a facile method. The HA integrated with CM/MWCNTs composites-based electrochemical sensor exhibited synergistic effects: (i) the abundant hydrophilic groups in the HA structure (water contact angle, 30.88°) facilitated the formation of a hydrated layer on the electrode surface to prevent fouling; (ii) CM/MWCNTs catalyzed the electrooxidation of dopamine; (iii) electrostatic interactions between the negatively charged HA/CM/MWCNTs and positively charged dopamine in neutral condition. The morphology and structure of the nanocomposite were characterized. The HA/CM/MWCNTs-modified electrode exhibited the improved hydrophilicity with a water contact angle of 30.92° and enhanced electrochemical response of the modified electrode for dopamine sensing in a variety of conditions with protein in the electrolyte. Moreover, the HA/CM/MWCNTs-modified sensor also exhibited superior dopamine analytical performance in human serum samples, with the dopamine detection accuracy approaching 97 % and be interference-free from proteins. The constructed electrochemical sensor presented great potential in dopamine detection in clinic setups.