Add to ORKGThe invention relates to a method and an apparatus (100) for the processing of nucleotide sequences. An apparatus (100) according to an embodiment of the invention comprises an array of electrodes (120a,120b,...), wherein at least one nanoball (NB) comprising replications of a nucleotide sequence (1,2) of interest is attached to an electrode to which only one nanoball (NB) of that size can be attached at the same time. Thus a unique association of electrodes (120a,120b,...) to nucleotide sequences (1,2) of interest can be achieved. The nanoballs (NB) are preferably produced by rolling circle amplification. Application of attractive and/or repulsive electric potentials to the electrodes (120a,120b,...) can be used to control the attachment o...