AFM1 Detection in Milk by Fab' Functionalized Si3N4 Asymmetric Mach-Zehnder Interferometric Biosensors

Toxins (Basel). 2019 Jul 14;11(7):409. doi: 10.3390/toxins11070409.


Aflatoxins (AF) are naturally occurring mycotoxins, produced by many species of Aspergillus. Among aflatoxins, Aflatoxin M1 (AFM1) is one of the most frequent and dangerous for human health. The acceptable maximum level of AFM1 in milk according to EU regulation is 50 ppt, equivalent to 152 pM, and 25 ppt, equivalent to 76 pM, for adults and infants, respectively. Here, we study a photonic biosensor based on Si 3 N 4 asymmetric Mach-Zehnder Interferometers (aMZI) functionalized with Fab' for AFM1 detection in milk samples (eluates). The minimum concentration of AFM1 detected by our aMZI sensors is 48 pM (16.8 pg/mL) in purified and concentrated milk samples. Moreover, the real-time detection of the ligand-analyte binding enables the study of the kinetics of the reaction. We measured the kinetic rate constants of the Fab'-AFM1 interaction.

Keywords: Aflatoxin M1; Fab’; affinity; asymmetric Mach–Zehnder interferometer; lab-on-chip; limit of detection; optical biosensors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aflatoxin M1 / analysis*
  • Aflatoxin M1 / chemistry
  • Aflatoxin M1 / immunology
  • Animals
  • Biosensing Techniques*
  • Enzyme-Linked Immunosorbent Assay
  • Food Contamination / analysis*
  • Immunoglobulin Fab Fragments / chemistry
  • Immunoglobulin Fab Fragments / immunology
  • Interferometry
  • Light
  • Milk / chemistry*
  • Silicon Compounds / chemistry


  • Immunoglobulin Fab Fragments
  • Silicon Compounds
  • Aflatoxin M1
  • silicon nitride