Assessment of a crustacean allergen in fishery products using a nanomodified label-free voltammetric immunosensing approach

• A simple but robust label-free immunoassay can detect the allergen tropomyosin in 1 h. • The analytical signal was enhanced using a (bio)modified electrode. • The biosensor demonstrates a storage stability of 28 days. • Traces of tropomyosin were successfully quantified in seafood using the developed immunosensor. In this work, a label-free immunosensor for the rapid analysis of the crustacean allergen tropomyosin (TPM) is presented. A screen-printed carbon electrode (SPCE) was (bio)modified with oxidized carbon nanotube/manganese(II) ferrite nanomaterial (CNT_O@MnFe 2 O 4 ) and monoclonal antibodies. The immune interaction with the allergenic protein was detected using a redox probe ([Fe(CN) 6 ] 3−/4− ) by differential pulse voltammetry. The CNT_O@MnFe 2 O 4 led to a 4-fold increase of the analytical signal compared to the unmodified SPCE, indicating the usefulness of this material in TPM analysis. Moreover, the detection potential was reduced (i.e., closer to 0 V), which increased the selectivity of the sensor even further. The immunosensor enabled a fast analysis time (1 h), providing a limit of detection of 1.6 ng mL −1 , and precise results (coefficient of variation = 6.5 %). The analysis of ten commercial foodstuffs was accomplished, and the results were validated with an ELISA assay. The highest TPM concentrations were quantified in shrimp species ( M. affinis > P. latisulcatus > P. indicus ) and low allergen levels were found in surimi lobster, clam, fresh calamari, and mayonnaise. The simplicity of the sensor makes it a good choice for quality control and food safety assessment in industrial settings.