Silver Microneedle Array Printed via Aerosol Jet Enhance the Electrochemical Detection of Carboxylated Carbon Nanotubes for Chloramphenicol

Chloramphenicol (CAP) is a potent broad-spectrum antibiotic that has been restricted for use in food producing animals in many countries due to its serious side effects. Therefore, there is an urgent need for rapid and sensitive detection of CAP. In this study, 3-D electrochemical sensing electrode with high sensitivity to CAP was developed, which consisted of aerosol jet printed silver microneedle modified by carboxylated multiwalled carbon nanotubes (MWCNTs-COOH). The silver microneedle arrays provide a 3-D porous structure and rapid electron transfer pathways for MWCNTs-COOH. As a result, the obtained screen-printed carbon working electrode (SPCE)/ $\mathrm{Ag}_{{10} \times {10}}$ @CNTs electrode exhibits a limit of detection (LOD) of 0.073 $\mu $ M and a high sensitivity of $18.86~\mu $ A/( $\mu $ M $\cdot $ cm2) toward CAP. The modified electrode demonstrates excellent selectivity, stability, reproducibility, and repeatability toward CAP. Moreover, the electrochemical sensor was applied to determine CAP in real samples with satisfactory results.