Author(s)

Katia Spinella, Lucia Mosiello, Giuseppe Palleschi, Fabio Vitali

Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Rome, Italy.
ENEA, Italian National Agency for New Technologies, Energy and the Environment, Rome, Italy.

In this study, we have used a direct immunoassay where the simple binding between antigen and an antibody is detected. Immunoassays were performed in a drop system, monitoring the frequency decrease of the quartz-crystal microbalance device because of mass increasing during immunoreaction. The QCM sensor was coated on both sides by gold electrodes, only one side of the crystal (liquid side) was in contact with the solution; the other side (contact side) was always dry. We tested a piezoelectric immunosensor for aflatoxin B1 (AFLA-B1) mycotoxin detection through the immo- bilization of DSP-anti-AFLAB1 antibody (AFLA-B1-Ab anti AFLAB1) on gold-coated quartz crystals (AT-cut/5 MHz). The DSP (3,3’-Dithiodipropionic-acid-di-N-hydroxysuccinimide ester) was used for the covalent attachment of the proteins. The piezoelectric crystal electrodes were pretreated by DSP for 15 min, rinsed with water and dried in a gentle flow of nitrogen gas. Then the DSP-coated crystals were installed in a sample holder and exposed to the anti-AFLAB1 antibody and to the AFLA-BI. Frequency and resistance shifts (Δf and ΔR) were measured simultaneously. Δf versus AFLA-BI concentrations in the range of 0.5 - 10 ppb exhibited a perfect linear correlation with a coefficient of above 0.998.

Immunosensor; Quartz Crystal Microbalance; Aflatoxin B1; Antibody; Gold Electrodes

Spinella, K. , Mosiello, L. , Palleschi, G. and Vitali, F. (2013) Development of a QCM (Quartz Crystal Microbalance) Biosensor to the Detection of Aflatoxin B1. Open Journal of Applied Biosensor, 2, 112-119. doi: 10.4236/ojab.2013.24015.