Electrochemical Sensing of DNA with Porous Silicon Layers

Abstract

The nanostructure known as porous silicon is an excellent material for sensing applications. Due to its large internal surface, it is capable of adsorbing an enormous amount of different compounds. The average porous size can be easily adjusted to allow the pene- tration of molecular compounds with different sizes. In this work we show a sensing application for porous silicon. We have fabricated a biosensor from DNA. The biosensor is an electrochemical device that transduces the hybridization of DNA into a chemical oxidation of guanine by , the reduced form of which is then detected electrochemically. The anodic peak current of was linearly related to the target DNA sequence in the range 0.5×10 -10 - 500×10 -10 M with a detection limit of 0.5×10 -10 M. In addition the ruthenium bipyridine indicator was able to selectively discriminate against different DNA sequences; a necessary property for sensing applications. + 2 3 ) (bpy Ru + 2 3 ) (bpy Ru