title: In-vivo dynamic characterization of microneedle skin penetration using optical coherence tomography.
abstract: The use of microneedles as a method of circumventing the barrier properties of the stratum corneum is receiving much attention. Although skin disruption technologies and subsequent transdermal diffusion rates are being extensively studied, no accurate data on depth and closure kinetics of microneedle-induced skin pores are available, primarily due to the cumbersome techniques currently required for skin analysis. We report on the first use of optical coherence tomography technology to image microneedle penetration in real time and in vivo. We show that optical coherence tomography (OCT) can be used to painlessly measure stratum corneum and epidermis thickness, as well as microneedle penetration depth after microneedle insertion. Since OCT is a real-time, in-vivo, nondestructive technique, we also analyze skin healing characteristics and present quantitative data on micropore closure rate. Two locations (the volar forearm and dorsal aspect of the fingertip) have been assessed as suitable candidates for microneedle administration. The results illustrate the applicability of OCT analysis as a tool for microneedle-related skin characterization.
authors.affiliation: University of Limerick, Department of Physics, Tissue Optics and Microcirculation Imaging Facility, National Biophotonics and Imaging Platform, Limerick, Ireland.
authors.forename: Joey
authors.initials: J
authors.lastname: Enfield
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: O'Connell
authors.forename: Kate
authors.initials: K
authors.lastname: Lawlor
authors.forename: Enock
authors.initials: E
authors.lastname: Jonathan
authors.forename: Conor
authors.initials: C
authors.lastname: O'Mahony
authors.forename: Martin
authors.initials: M
authors.lastname: Leahy
mesh_terms: D000818:Animals; D055119:Elastic Modulus / Q000502:physiology; D006244:Hardness / Q000502:physiology; D008904:Miniaturization; D009339:Needles; D012867:Skin / Q000166:cytology*; D012879:Skin Physiological Phenomena; D013552:Swine; D041623:Tomography, Optical Coherence / Q000379:methods*