In various embodiments a molecular circuit is disclosed. The circuit comprises a negative electrode, a positive electrode spaced apart from the negative electrode, and a binding probe molecule conductively attached to both the positive and negative electrodes to form a circuit having a conduction pathway through the binding probe. In various examples, the binding probe is an antibody, the Fab domain of an antibody, a protein, a nucleic acid oligomer hybridization probe, or an aptamer. The circuit may further comprise molecular arms used to wire the binding probe to the electrodes. In various embodiments, the circuit functions as a sensor wherein electrical signals, such as changes to voltage, current, impedance, conductance, or resistance in the circuit, are measured as targets interact with the binding probe. In various embodiments, the circuit provides a means to measure the presence, absence, or concentration of an analyte in a solution.