(Georgia Institute of Technology, 2008-04-09)
Alexander, John D.
The purpose of this project was to perform a series of bench tests to evaluate
particular aspects the Skin Interrogation Device (SID), a prototype instrument designed to
measure the in-vivo mechanical properties of human skin. Among its many potential uses, the
device may help to detect and monitor debilitating diseases and assess the effectiveness of
therapeutic interventions. (Objectives) A paucity of research has been conducted to assess the
prototype's actual ability to measure mechanical properties. Therefore, this became a major
objective of the current project, with two specific aims: (1) evaluate the prototype's ability to
differentiate a range of materials, and (2) define the relationship between the prototype's output
and known properties of the tested materials. (Methods) 12 different commercially available
prosthetic liners were used as test materials, the properties of which have been reported in detail
by Sanders et al, 2004. Each liner was tested under tightly controlled conditions using the SID
and a bench-top positioning device. (Results) A one-way ANOVA and subsequent Tukey posthoc
tests revealed that the SID prototype was able to successfully differentiate 55 of 66 (83%)
pairs of liner comparisons (a = 0.05). Linear regression analysis for the relationship between the
device output and the liners' reported shear modulus properties yielded an R value of 0.834.
(Conclusions) First, changes in the measurements from the prototype SID do indeed appear to
reflect actual changes in the stiffness properties of tested materials. Second, the prototype does
indeed seem capable of differentiating materials that have differences in these stiffness
properties. (Future Work) In the future, tests of physical models with incremental property
variations will help further the understanding of the device's sensitivity to changes in human
skin. Also, human subject trials will further validate the device's utility in the clinical setting.