Contactless Bio‐Electrofunctionalization of Planar Micropores

Abstract The localized functionalization of pores and channels of micrometric and sub‐micrometric sizes is a bottleneck in surface chemistry. A method for the regioselective chemical functionalization of planar pores is presented, that are, restrictions in microfluidic channels, here made of SiO 2 ‐coated silicon. This strategy, based on bipolar electrochemistry, exploits the combined presence of the constriction and a localized deoxidation pattern within the pore that affects the electrical field distribution inside the microfluidic channel. It is not only shown that it is capable of regioselectively functionalizing a planar pore at relatively small potential difference applied across it, but also the possibility of positioning the functionalization area inside or at the edges of the pore depending on the design of the deoxidation pattern is proved. These results are in perfect correlation with the numerical simulations of electric field distribution in micropores carried out using the software Comsol Multiphysics. This functionalization technique is therefore very promising, particularly in the field of biosensors. A specific DNA hybridization test has been successfully carried out, which represents a first step toward bioanalytical and health applications.