Optical poration, or drilling, of the human nail has the potential to drastically improve transungual drug delivery. However, this approach is accompanied by thermal damage to the nail tissue surrounding the laser radiation-created pore. In this paper, fluorescence microscopy has been employed to quantitatively evaluate thermal damage to the nail induced by laser ablation with 80 MHz, nanojoule, femtosecond pulses delivered via a hollow-core fibre. An empirical relation has been established between the intensity of the resulting fluorescence signal and temperature to which the nail was exposed. Using this relationship, detailed temperature maps have been created of the areas surrounding the pores, enabling the mechanism of poration to be better understood. It was deduced that plasma-mediated ablation is primarily responsible for nail tissue ablation at the centre of the pore, while cumulative photothermal processes dominate at the pore edges. It is concluded, furthermore, that temperature mapping represents a useful new tool with which to optimise the process of nail poration. The method is potentially generic and may be applicable to other biological materials.

Original languageEnglish
Pages (from-to)956–967
Number of pages12
JournalDrug Delivery and Translational Research
Issue number5
Early online date23 Apr 2019
Publication statusPublished - 31 Oct 2019


  • Drug delivery
  • Femtosecond pulsed laser ablation
  • Fluorescence microscopy
  • Human nail
  • Nail poration
  • Thermal mapping

ASJC Scopus subject areas

  • Pharmaceutical Science


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