Fabrication of zinc tetramethoxyphenyl porphyrin-CNTs nanosensor for efficient sensing of the anticancer drug, 5-fluorouracil in human serum

5-Fluorouracil (5-FU) is a widely used anticancer drug for treating various types of cancer. Rapid and precise monitoring of 5-FU is critical to minimize its adverse effects on patients. This study presents the synthesis and application of a zinc tetramethoxyphenyl porphyrin-carbon nanotubes (ZnTMPP-CNTs) composite-based electrochemical sensor for detecting 5-FU. The sensor was developed by modifying a glassy carbon electrode (GCE) with the ZnTMPP-CNTs composite, which was synthesized via a one-step process. Comprehensive characterization of the composite was conducted using UV–visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectroscopy, and scanning electron microscopy (SEM). The modified GCE was fabricated using a drop-casting method. Electrochemical performance was assessed through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The modified GCE performed superior to the bare electrode in a 0.1 M phosphate buffer solution (PBS) at pH 7. The electro-oxidation mechanism of 5-FU was identified as a one-electron process, primarily adsorption-controlled on the modified electrode's surface. The sensor demonstrated a linear response in the concentration ranges of 0.1 - 1.0 μM and 2.0 - 14.0 μM, with a sensitivity characterized by a limit of detection (LoD) of 0.098 μM and a limit of quantification (LoQ) of 0.327 μM. The sensor showed excellent stability, repeatability, and reproducibility. Its practical applicability was validated with real human blood serum samples, achieving remarkable recovery results. This research highlights the sensor's potential industrial, environmental, and medical applications, particularly in monitoring 5-FU in clinical settings.