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 (Fe3O4@MOF@Pt), which exhibit high peroxidase-like catalytic activity, magnetism, and superior optical properties. The surface of Fe3O4@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 H2O2 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% to 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.