Ultrasensitive composite electrochemical sensor with printed wrinkled CNTs nanostructure for simultaneous detection

Abstract

Combining biomimetic and 3D printing has created new opportunities for the manufacture of electrochemical sensors. Dopamine (DA) and Uric acid (UA) are common body electroactive substances, and their detection is important for diagnosing metabolic diseases. Metal electrochemical sensors have limitations in sensitivity and selectivity due to their smooth 2D structures, which make it challenging to capture comprehensive electrochemical information. Here, inspired by taste buds, an ultrasensitive CNT-Pt composite electrochemical sensor, including a printed biomimetic wrinkled CNTs film, was prepared for simultaneous detection of DA and UA. Nanoscale Pt electrode was prepared by UV-LIGA process and the wrinkled CNTs nanofilm was fabricated by thermally assisted electrohydrodynamic jet (E-Jet) printing. CNT lines of 3∼58 μm, droplets of 4 μm and 2D array structures have been printed. The enhanced sensing mechanism of wrinkled CNTs nanofilm was analyzed theoretically. The nanoscale wrinkled morphology (nanofolds∼50 nm) and hydrophilicity (CÃ20°) of printed wrinkled CNTs nanofilm were analyzed. The anodic peak potential for UA was observed to range from 0.429 V to 0.489 V for the conventional Pt electrochemical sensor, whereas it ranged from 0.205 V to 0.276 V for the CNT-Pt composite electrochemical sensor. The detection performance of CNT-Pt composite electrochemical sensor was improved by ∼40 % contrast with Pt electrochemical sensor. The prepared composite electrochemical sensor can effectively recognize DA, UA and AA. From analysis, the peak value of AA was not obvious, the peak values of DA and UA were 0.096 V and 0.265 V. The composite electrochemical sensor successfully eliminated the detection interference caused by AA in detecting DA and UA. The nanoscale composite electrochemical sensor and its hybrid manufacturing method provide great potential for electrochemical testing applications.