Electrical sensing of DNA hybridization in porous silicon layers

The objective of this work is to use porous silicon (PSi) layers as substrate material to transduce hybridization of DNA into a change in conductance. A coplanar configuration of the contact electrodes allows a complete exposure of the porous silicon layer to the sensing species without the need of top contacts or electrolyte solutions. Synthetic oligonucleotides were infiltrated into the porous silicon layers to sense the hybridization event. Hybridization of a single base sequence to its complementary strand was used as a model to demonstrate the response of the layer to the binding of complex sequences. We hypothesize that the observed response involves the activity of surface states present at the silicon-silicon dioxide (Si-SiO2) interface and sensitive to the change in charge at the surface of the layer.