Colorimetric aptasensor based on Fe3O4@MOF@Pt nanozymes for ultrasensitive detection of histamine in fish

The accurate determination of histamine in fish is imperative for food safety, given the toxic nature of this biogenic amine . This study presents an innovative colorimetric aptasensor for the ultrasensitive detection of histamine in fish, utilizing nanozymes based on magnetic metal-organic frameworks coated with Pt nanoparticles (Fe 3 O 4 @MOF@Pt), which exhibit high peroxidase-like catalytic activity, magnetism, and superior optical properties. The surface of Fe 3 O 4 @MOF@Pt nanozymes were modified with DNA strands complementary to the histamine aptamer , creating effective colorimetric probes. In the presence of histamine, these colorimetric probes compete with histamine molecules for aptamer binding on the enzyme plate. Color development is triggered by adding a TMB and H 2 O 2 substrate solution to the enzyme plate. This competitive binding-based aptasensor allows for rapid and accurate histamine quantification within a linear range of 10 pM to 10 μM, and a notable detection limit of 6.23 pM. Furthermore, the sensor demonstrated excellent specificity, distinguishing histamine from l -histidine and other biogenic amines. Tested on mackerel samples, the aptasensor showed spiked recoveries of 91.4%–109.6%, validating its practical applicability. This sensor offers an ultrasensitive, specific, and reusable tool for histamine detection, representing a significant advancement in ensuring the safety of fish products.