A process for making a biosensor comprising a hollow coil comprising wires coiled in parallel and an electronic circuit component connected to the coil, the process comprising: 1) providing a mandrel on which wires including at least a first wire, a second wire and a third wire are wound in parallel, 2a) immersing the mandrel in a first buffer solution comprising a first bioreceptor, a first monomer and optional additives, 2b) arranging the wires such that the second wire is used as a working electrode, the first wire is used as a counter electrode and the third wire is used as a reference electrode of a three electrode electrochemical cell used in an electropolymerisation process, 3) passing electric current through the second wire to form a first biocompatible coating of a first polymer polymerized from the first monomer comprising the first bioreceptor on the second wire, 4) removing the coil from the mandrel, 5) connecting the wires to their respective points of the electronic circuit component such that the second coil is used as a working electrode, the first wire is used as a counter electrode and the third wire is used as a reference electrode, wherein the electronic circuit component is configured such that it can generate an input signal for a wireless receiver based upon the activity of the bioreceptor and wirelessly send the input signal to the wireless receiver, wherein the first monomer is an optionally substituted five-membered heterocycle of formula wherein R 1 stands for a hetero atom, preferably N, S or O, wherein R 2, R 3 are each independently selected from the group of H, optionally substituted alkyl of preferably 1 to 4 C atoms, wherein the alkyl may be substituted with for example a hydroxyl group, alkyl group and alkyl ether, optionally substituted o-alkyl, and wherein R 2 and R 3 may form a ring together with the carbon atoms to which they are connected and wherein the bioreceptor is an oxidoreductase. 1) providing a mandrel on which wires including at least a first wire, a second wire and a third wire are wound in parallel, 2a) immersing the mandrel in a first buffer solution comprising a first bioreceptor, a first monomer and optional additives, 2b) arranging the wires such that the second wire is used as a working electrode, the first wire is used as a counter electrode and the third wire is used as a reference electrode of a three electrode electrochemical cell used in an electropolymerisation process, 3) passing electric current through the second wire to form a first biocompatible coating of a first polymer polymerized from the first monomer comprising the first bioreceptor on the second wire, 4) removing the coil from the mandrel, 5) connecting the wires to their respective points of the electronic circuit component such that the second coil is used as a working electrode, the first wire is used as a counter electrode and the third wire is used as a reference electrode, wherein R 1 stands for a hetero atom, preferably N, S or O, wherein R 2, R 3 are each independently selected from the group of H, optionally substituted alkyl of preferably 1 to 4 C atoms, wherein the alkyl may be substituted with for example a hydroxyl group, alkyl group and alkyl ether, optionally substituted o-alkyl, and wherein R 2 and R 3 may form a ring together with the carbon atoms to which they are connected and wherein the bioreceptor is an oxidoreductase.