A method of manufacturing a biosensor having a microbeam linked to a support, at least one electrode a biological molecule A grafted onto the microbeam in a different zone from the zone where the electrode is embedded, and a mechanoelectrical transducer for converting variations of the mechanical properties of the microbeam into an electrical signal, when the biological molecule A is placed in contact with a biological molecule B to be detected and/or quantified. The method includes: formation of an electrode on fluoropolymer material sheet, passivation of the electrode(s), creation of the form of the biosensor in the sheet of polymer material and separation of this form from the sheet, functionalization either of a prefunctionalized zone or of a zone of the microbeam, this zone being different from the zone wherein the electrode is embedded, and grafting of a biological molecule A onto the functionalized zone.