Biological functionalization of massively parallel arrays of nanocantilevers using microcontact printing

In this paper, we present a back-end method for biofunctionalizing a large-scale array of nanocantilevers. Our method relies on the use of a modified microcontact printing process where molecules are delivered onto the fragile structures from the grooves of the stamp while its base sits on the chip, thus providing mechanical stability. We have used this method to print antibodies onto fabricated chips containing up to 105 nanostructures/cm2and the presence of antibodies was validated by fluorescent microscopy. Furthermore, measurement of the nanocantilever resonant frequency shifts provoked by a mean added mass of ∼140 fg/cantilever demonstrated that the cantilevers retained their mechanical integrity. Hence, the method presented here aims at providing an answer to the biofunctionalization of freestanding nanostructures for their use as biosensors.