Microneedle device samples fluid from skin

Abstract

Applying a microneedle patch to the skin might one day replace the uncomfortable needle stick required to perform some blood tests. As a step toward that goal, researchers have demonstrated a prototype device that combines microneedles and plasmonic sensor paper to sample interstitial fluid from the skin and analyze it directly using surface-enhanced Raman spectroscopy (SERS) (ACS Sens. 2019, DOI: 10.1021/acssensors.9b00258). Mark R. Prausnitz of the Georgia Institute of Technology, Srikanth Singamaneni of Washington University in St. Louis, and colleagues demonstrated their device by detecting a positively charged fluorescent dye, rhodamine 6G, infused into rats. The researchers grew gold nanoparticles and coated them with negatively charged poly(4-styrenesulfonic acid). Then they concentrated the coated nanoparticles into an ink, wrote the ink onto a strip of filter paper, and attached the paper to a strip of 650 µm long steel microneedles. After applying the microneedles to the skin of hairless rats se...