  A method for the direct patterning of electrostatic potential at the surface
of hydroxyapatite is presented here. Micro-domains of surface potential have
been created on hydroxyapatite coatings by a 20 keV focused electron beam with
minimal alterations of surface chemistry. The success of such approach has been
confirmed by Kelvin Probe Force Microscopy measurements, which show that this
method is capable of creating micron sized positive and negative local
electrostatic potential. The shape and potential difference of these domains
were found to depend on the dose of total injected charge from the electron
beam as well as the speed with which such charge is injected.
