A modified method using the SonoPrep ultrasonic skin permeation system for sampling human interstitial fluid is compatible with proteomic techniques.

Background: The use of biomarkers in skin is a novel diagnostic tool. Interstitial fluid (ISF) from skin provides a snapshot of proteins secreted at the time of sampling giving insights into the patient's health status. Methods: A minimally invasive technique for the transdermal collection of human ISF proteins. A low frequency ultrasonic skin permeation device (SonoPrep (R) ultrasonic skin permeation system) was used to produce micropores in the stratum corneum through which ISF was extracted using a portable pulsed vacuum ISF collection device. Results: On average, protein concentrations recovered ranged between 0.064 and 4.792 mu g/mu L (mean 1.258 mu g/mu L). Two-dimensional gel electrophoresis revealed that this sample type was amenable to this type of analysis. Gel images indicated that both highly abundant proteins and lower abundance proteins were isolated from the skin. Western blot analysis confirmed the presence of proteins commonly found in plasma and the epidermis. Conclusion: A minimally invasive method for the transdermal recovery of ISF proteins has been developed. We have demonstrated that ISF samples obtained using this approach can be analysed with proteomic techniques, such as two-dimensional gel electrophoresis and western blots, providing another tool for the identification of disease specific protein biomarkers.