Mechanisms of sampling interstitial fluid from skin using a microneedle patch

Significance Diagnosis and monitoring of disease is often done by measuring biomarkers found in blood, urine, saliva, and other bodily fluids. Another rich source of biomarkers is the interstitial fluid that surrounds cells and tissues in the body, but difficulty in accessing this fluid has limited its use in research and medicine. Here, we conducted experimental studies coupled with theoretical modeling to design a patch containing microscopic needles that puncture into superficial layers of skin and thereby enable withdrawal of interstitial fluid through micropores in a simple, minimally invasive manner. This patch can help researchers access interstitial fluid to advance discovery of novel biomarkers and enable doctors to use interstitial fluid for possible future diagnosis and monitoring of disease.