Silicon biosensor microprobes for the in vivo detection of neurotransmitters are equipped with removable clips for an on-chip functionalisation technique that allows a simple and comfortable but very local and reproducible deposition of sensitive layers on dedicated microelectrodes. It can been seen as an alternative to high-priced low-volume dispensing equipment or electro-chemical setups since not only coatings of a) several electrodes in parallel or b) closely spaced electrodes with different substances are possible, but additionally it can be performed directly before use with a conventional micropipette.