A molecular probe includes a detector molecule specific to a target molecule, and at least one label linked covalently or non-covalently to the detector molecule. The label includes a catalyst for generating electrons and/or mediators from a solution. The catalyst includes a nanomaterial, an enzyme, a metal, and/or a metal complex. The mediators can accumulate in the solution for a period of time. The detector molecule and the target molecule interact with each other by a protein based or nucleotide sequence based interaction. The mediators participate in a chemical reaction that generates a signal that may be a change in optical, electromagnetic, thermodynamic or mechanical properties. Generation efficiency of the mediators is enhanced by providing an energy to the solution. The molecular probe may be used with a molecular detection assay performed on a surface. A method for assaying the target molecule using the molecular probe is also provided.