Nickel monoligand-MOF modified electrochemical sensor for the detection of neuroblastoma biomarker homovanillic acid

Early cancer detection is vital for successful clinical outcomes and for advancing public health. It is crucial to detect cancer early for prevention and better treatment. Electrochemical sensors have been developed for disease detection, especially cancer, based on biomarkers, due to their sensitivity, selectivity, affordability, and rapid response. Neuroblastoma is a pediatric cancer originating from neural crest stem cells and is the most prevalent extracranial tumour in infants. The current study discusses the development of an electrochemical sensor for the detection of homovanillic acid (HVA), a tumour biomarker for neuroblastoma and other dopamine-related disorders. The electrochemical oxidation of HVA was investigated utilizing a carbon paste electrode modified with a nickel-based monoligand complex (ML/Ni–MOFs/CPE). This modification significantly improved the electrode's sensitivity and electrocatalytic efficiency. Under optimized conditions, the sensor displayed a linear DPV response within the concentration range of 0.1 μM to 70.0 μM and achieved a low detection limit of 0.08 μM. Morphological and elemental analyses were carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), and infrared spectroscopy (FT-IR). These characterizations confirmed the uniform dispersion of nickel anchored onto the MOF sheets. Electrochemical performance was further evaluated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The ML/Ni–MOFs/CPE electrode exhibited a markedly enhanced HVA oxidation peak current compared with the bare CPE, indicating improved electron transfer kinetics. The electrode demonstrated high reproducibility (RSD < 2 %) and stability, along with good selectivity against common interferents such as creatinine, ascorbic acid, uric acid, and glucose. Application to spiked human urine samples yielded recovery values between 93.25 % and 97.60 %, confirming its analytical accuracy and reliability in biological matrices. The modified electrode retained over 90 % of its initial response after 60 days of storage under ambient conditions, demonstrating outstanding stability and durability. These findings highlight the potential of the proposed ML/Ni–MOFs/CPE sensor as a rapid, cost-effective, and reliable platform for HVA detection. Its robustness and successful application to urine samples highlight its potential for clinical diagnostics and early neuroblastoma diagnosis, supporting future integration into portable and point-of-care testing systems. • A sensitive electrochemical sensor for HVA detection, a neuroblastoma biomarker. • Nickel monoligand-modified CPE enhanced electron transfer and sensitivity. • The developed sensor achieved a low detection limit and stable performance • The sensor was successfully applied to urine samples for early POC cancer detection.