Abstract

Serotonin (5-HT) is an important neurotransmitter and key biomarker associated with diabetes and neurological disorders. Abnormal 5-HT levels are linked to several pathological disorders, highlighting the need for sensitive and selective detection strategies. However, direct electrochemical finding using bare electrodes is often limited by low sensitivity, surface fouling, and interference effects. Herein, a novel electrochemical detection platform based on a Cu-MOF/CNFs/MoS2 (Cu-metal organic framework/carbon nanofibers/Molybdenum disulfide) hybrid composite integrated with PPS (poly(phenosafranine)/Nafion polymeric film was developed for ultrasensitive, fouling and interference-resistant 5-HT detection. The Cu-MOF/CNFs/MoS2 composite was synthesized in a solvothermal manner, while the PPS/Nafion layer enhanced charge transfer kinetics, regulated electroactive sites, and improved electrode stability. The fabricated sensor exhibited a broad linear concentration range of 100 pM-1000 & micro;M, an ultralow detection limit of 18.53 pM (3 sigma/slope), and a high sensitivity of 0.639 & micro;A & micro;M-1 cm-2. In addition, the sensor demonstrated excellent selectivity, reproducibility, stability (electrode stored at 4 degrees C and 25 +/- 2 degrees C), and anti-interference capability. The practical sample applicability was validated using complex human blood and urine samples, showing satisfactory recoveries (97.90-100.95%, n = 3) with low relative standard deviation (RSD) values (1.03-2.24%, n = 3). Furthermore, a portable point-of-care sensor strip was developed for rapid and direct biofluid analysis.