The self-assembly of TiO2 nanoparticles is used to create a high index layer within a structured optical fibre. We show both experimentally (using a novel porphyrin probe) and theoretically that this approach leads to more than order of magnitude enhanced localisation of the optical field at the layer-air interface of the hole, both through edge localisation and through novel resonance localisation as a result of a ring resonator whispering gallery modes.