Electrochemical biosensors by in situ dissolution of self-assembled nanolabels into small monomers on electrode surface

•We proposed a strategy for designing of singal labels used for electrochemical biosensors.•The nanolabels were prepared by the self-assembly of small molecules.•Large number of electroactive elements were concentrated on electrode surface by in situ dissolution.•Prostate specific antigen and cancer cells as the model analytes were determined with satisfactory results. Nanomaterials composed of electroactive elements have increasingly being used as the signal labels of electrochemical biosensors. In this work, we proposed a novel strategy for the preparation of signal labels used for electrochemical biosensors. The method is based on the signal amplification of self-assembled nanomaterials of small molecules and the in situ dissolution of nanostrutures into electroactive elements on electrode surface. Ferrocenoyl phenylalanine (Fc-F) nanoparticles (FcFNPs) were prepared and used as the example of signal labels. The FcFNPs captured by sensor electrode were in situ disassembled into tens or hundreds of monomers by methnol. After evaporation of methnol, the released Fc-F monomers were concentrated on electrode surface to produce a strong electrochemical signal. With prostate specific antigen and cancer cells as the model analytes, the target concentration as low as 1 pg/mL or 10 cells can be readily measured. This work should be valuable for designing of novel nanolabels and development of sensitive sensing platforms.