Synergistic specific recognition of melatonin in milk using biocompatible molecularly imprinted electrochemical sensor based on MWCNTs/CS

An electrochemical MIP sensor for MT was developed. • MT recognition via hydrogen bonding/π-π stacking and electrostatic interactions. • This sensor was simple, rapid, sensitive, and highly selective. • The sensor achieves the detection of MT in milk and serum. The detection of melatonin (MT) is essential for the clinical diagnosis of mental illnesses. In this study, a glassy carbon electrode (GCE) was modified with carboxylated multi-walled carbon nanotubes (MWCNTs) and chitosan (CS) to enhance its electrical conductivity and adhesiveness. L-tyrosine (L-tyr) was selected as the functional monomer and electropolymerized with MT to form the biocompatible MIP-MT imprinted layer. The specific recognition of MT by MIP-MT is facilitated by hydrogen bonding and π - π interactions between L-tyr and MT. Additionally, the electrostatic interaction between positively charged CS and negatively charged MT further contributes to the synergistic recognition with MIP-MT. Under optimized conditions, the IF value of MIP-MT reached 3.6. Furthermore, MIP-MT exhibited a detection limit of 0.0979 μM for MT and showed a linear relationship within the range of 0.1–100 μM. MIP-MT demonstrated recovery rates of 93.86%–99.14% in milk, presenting an innovative approach for disorders associated with MT biomarker levels. Download: Download high-res image (175KB) Download: Download full-size image