The present invention relates to an apparatus for detecting one or more analytes, for example analytes selected from the group comprising nucleic acids, metabolites, peptides, proteins, hormones, pesticides, neurotransmitters, ions in blood, electrolytes, toxic gases, pH and
biological warfare agents, the apparatus comprising an insulating substrate, at least one first
electrode on the substrate at least one elongate
nanostructure extending from and electrically connected to the or each said
electrode and extending over the surface of the
wafer away from the respective
electrode, a passivating layer covering the or each electrode, but not all of said at least one elongate
nanostructure, a well crossing the at least one elongate
nanostructure extending from the or each electrode and forming a static reservoir for a liquid being investigated for the presence of at least one
analyte, a
reference electrode provided on said substrate within said well or insertable into said well and respective readout pads electrically connected to the or each electrode and to the
reference electrode if the latter is provided on the substrate, the at least one elongate nanostructure being capable of being functionalized for detecting one or more analytes.