Abstract: A system and method for electrically detecting a target material in a sample without the need for labeling is described. A probe supporting member (8) defining at least one hole is functionalized with target specific probe material and a change in the hole area on binding of target material is detected as a change in an ionic current through the hole. In some embodiments, an electro-chemical cell comprising an electrode having a conducting layer (2) and a porous insulating layer (4) is provided. In some embodiments, an electrically addressable array (70) is provided for detection of a potentially large number of target materials in a sample.