Electrochemically etched sharp aluminium probes with nanoporous aluminium oxide coatings: demonstration of addressed DNA delivery

Electrochemical etching of metal wires is widely used to fabricate sharp probes for use in scanning tunnelling microscopy. In this work an electrochemical fabrication method for sharp aluminium probes coated with nanoporous anodised aluminium oxide (AAO) layer is described. The method presented here involves simultaneous anodisation and etching of aluminium wires. The probe apex radius as well as the nanopore length and diameter depend on the etching mode, which could be direct current (DC), alternating current (AC), or pulsed voltage mode (PVM). The probes, coated with a nanoporous AAO layer, were used to demonstrate addressed DNA delivery.