Preparation Of Flexible Boron-doped Diamond Microelectrodes And Their Application In Brain-computer Interface

Boron-doped diamond(BDD),a p-type semiconductor,has not only excellent electrical properties,but also the advantage of electrochemical performance with a wide potential window and low background current.So far,BDD electrodes have been mainly used in the development of electrochemical biochemical sensors for the detection of neurotransmitters and other biomolecules.Electroencephalography(EEG)is a bioelectrical signal generated by brain cells and originates from the electrochemical activity of brain cells,which makes the BDD electrode suitable as an epidermal electrode to collect scalp EEG signals.In this paper,a flexible BDD spiral electrode for EEG recording is developed and the application of flexible BDD-based EEG cap in brain-computer interface(BCI)is presented.For the flexible BDD electrode,the B-doping difference in the diamond crystal surface allows it to function as a microelectrode.Hydrogen bonding between hydroxy fatty acids in the stratum corneum and BDD surface terminals,and electrostatic adsorption between BDD-boron sites and the stratum corneum enhance the capacitive electric field.The BDD electrode cap combined with the simplest feature extraction and classification method allows recording highly stable EEG signals in the steady-state visual evoked potential(SSVEP)paradigm with an average signal-to-noise ratio of up to 8.6 d B.The BCI system exhibits competitive accuracy and information transfer rates in five channels in the occipital and parietal regions.In conclusion,the BDD-based SSVEP-BCI system offers unique advantages for real-time monitoring of brain signals,neurological rehabilitation and disease diagnosis...