variation, is in agreement with the same value obtained by
graphic interpolation in the calibration curve (Fig. 5, light cross
point).
In order to confirm these nanogravimetric results, a classical
Southern blotting analysis has been performed. Genomic DNAs
from transgenic biscuit and from a negative control (a GMO-free
sample), both EcoRI cut, were analyzed. The Cry1A(b) fragment
was used as positive control. The probe used for hybridization
was a biotinylated Cry1A(b) fragment. After chemiluminescent
detection, the hybridization has been detected only for positive
control and for transgenic biscuit DNA, as expected (Fig. 7).
These results provide a classical validation for the nanogravimetric
experiments, confirming the sensor’s ability to discriminate
the Cry1A(b) presence in free and not GM foods.