Bioelectronic devices have huge scientific and practical importance for basic science as well as for possible applications in medicine, the high-tech industry, the military, etc. The integration of biomaterials with electronic elements, such as electrodes, chips and transistors, yields hybrid systems that may function as biofuel cells, biosensors, and biocomputing devices. However, one of the main obstacles of bioelectronics lies in the poor electronic communication between the biocomponents and the electronic elements. The ultimate technological goal of the EU-funded 'Three-dimensional nanobiostructure-based self-contained devices for biomedical application' (3D-NANOBIODEVICE) project was to generate a hybrid bioelectronic system that could work in various biomatrices, such as blood, serum and plasma. From a scientific perspective, partners sought to understand the fundamental principles for controlling electron transfer reactions between gold nanoparticles (AuNPs), carbon nanotubes, as well as their 3D assemblies, and different bioelements. For this purpose, researchers chose to nanowire redox enzymes with AuNPs or carbon nanotubes, perform proper surface modifications, and use redox complexes. To produce such bioelectrodes with superior characteristics, the mathematical modelling of their performance was initially carried out and the results obtained from calculations were compared against experimentally determined parameters. The consortium successfully fabricated glucose and oxygen-sensitive three-dimensional bioelectrodes, which were used as biosensors, as well as bioanodes and biocathodes of biofuel cells. Biosensors were connected to electronic units consisting of a low-power radio transmitter, a voltage amplifier, and a micropotentiostat, all powered by biofuel cells. The signals from these hybrid biodevices, which corresponded to varying concentrations of bioanalytes, were transferred to a computer for processing. A novelty of the project was proof-of-principle demonstration of functional self-powered wireless biodevices for continuous glucose and oxygen monitoring in different biomatrices. This is expected to improve on quality of life and increase patient safety for chronic disease, such as diabetes.