A device for synthesis of macromolecules is disclosed. In one aspect, the device comprises an ion-releaser having a synthesis surface comprising an array of synthesis locations arranged for synthesis of the macromolecules. The ion-releaser also includes an ion-source electrode, which is arranged to contain releasable ions and is arranged to be in contact with each of the synthesis locations of the synthesis surface, thereby release ions to the synthesis locations. The ion-releaser further comprises activating electrodes, which are arranged to be in contact with the ion-source electrode, wherein each one of the activating electrodes is arranged in association with one of the synthesis locations via the ion-source electrode. The ion-releaser is arranged to release at least a portion of the releasable ions from the ion-source electrode to one of the synthesis locations, by activation of the activating electrode associated with the synthesis location.