A portable biosensor for the detection of cadmium-induced oral carcinogens in food

New type of electrochemical biosensor for ultrasensitive detection of Cd²⁺, which was a widely identified oral carcinogen, in food and water samples. The biosensor is assembled by the immobilization of multi-wall carbon nanotubes (MWCNTs), molybdenum disulfide (MoS 2 ) nanosheets and horseradish peroxidase (HRP) on a glassy carbon electrode (GCE). The synthesis and functionalization of the nanocomposite were also proved by characterization methods like SEM, XRD, FTIR and XPS. It was found that the synergism among MWCNT, MoS 2 , and HRP can largely strengthen the sensitivity and selectivity of the developed biosensor. The sensor showed a broad linear response range (5–920 μg/L) and a low detection limit (0.01 μg/L) and high sensitivity (3.1222μA/μg·L⁻¹). Its performance for sample analysis showed good selectivity toward interference ions, stability for more than 5 weeks, and high recovery values for analysis of real tap water, and food samples, indicating its potential practical applicability. The relationship between current and pH was examined, revealing that the peak current increases as the pH of the supporting electrolyte changes, with the optimal response observed at pH 6.5.The biosensor accuracy was confirmed by statistical evaluation with ICP-MS. This study presents a potential application for real time, on-site monitoring of cadmium, and it may also have further application to other environmental and food safety analytes. • Developed an ultrasensitive Cd²⁺ electrochemical biosensor. • MWCNT–MoS₂–HRP nanocomposite enhanced sensitivity and selectivity. • Wide detection range (5–920 μg/L) with 0.01 μg/L detection limit. • High stability (5+ weeks) and strong interference resistance. • Accurate results validated against ICP-MS in real samples.