title: Quantifying the mechanical properties of human skin to optimise future microneedle device design.
abstract: Microneedle devices are a promising minimally invasive means of delivering drugs/vaccines across or into the skin. However, there is currently a diversity of microneedle designs and application methods that have, primarily, been intuitively developed by the research community. To enable the rational design of optimised microneedle devices, a greater understanding of human skin biomechanics under small deformations is required. This study aims to develop a representative stratified model of human skin, informed by in vivo data. A multilayer finite element model incorporating the epidermis, dermis and hypodermis was established. This was correlated with a series of in-vivo indentation measurements, and the Ogden material coefficients were optimised using a material parameter extraction algorithm. The finite element simulation was subsequently used to model microneedle application to human skin before penetration and was validated by comparing these predictions with the in-vivo measurements. Our model has provided an excellent tool to predict micron-scale human skin deformation in vivo and is currently being used to inform optimised microneedle designs.
authors.affiliation: School of Engineering, Cardiff University, Queen's Buildings, The Parade, Cardiff, CF24 3AA, UK. sce5rbg@cardiff.ac.uk
authors.forename: R B
authors.initials: RB
authors.lastname: Groves
authors.forename: S A
authors.initials: SA
authors.lastname: Coulman
authors.forename: J C
authors.initials: JC
authors.lastname: Birchall
authors.forename: S L
authors.initials: SL
authors.lastname: Evans
mesh_terms: D019245:Compressive Strength / Q000502:physiology; D017076:Computer-Aided Design; D055119:Elastic Modulus / Q000502:physiology; D004867:Equipment Design; D020342:Finite Element Analysis; D006244:Hardness / Q000502:physiology; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D008845:Microinjections / Q000295:instrumentation* / Q000379:methods*; D008954:Models, Biological; D009339:Needles; D012879:Skin Physiological Phenomena; D013718:Tensile Strength / Q000502:physiology