A sample testing apparatus for characterizing at least one target molecule in a testing sample includes a substrate and at least one detection device over the substrate. Each detection device includes a plurality of electrodes, a plurality of data lines, and a probe. Each electrode is configured, upon reaction of the probe with one of the at least one target molecule, to sense an electrical signal, and then to transmit the electrical signal via the one data line. Each data line includes a first film layer and at least one other film layer disposed over the first film layer. The first film layer can be at a substantially same layer, and have a first composition substantially same, as the electrodes. One or more of the at least one other film layer can have a composition having a relatively lower electric resistance than the first composition.