Replacing Needles for Drawing Blood with Nearly Pain-Free Microneedle Patch to Test for Disease

    By Kathleen Berger, Executive Producer of Science & Technology

    Drawing blood can hurt, and veins can roll or burst. But doctors need blood samples to check for antibodies and biomarkers of disease. With more even blood samples needed to check for COVID-19 antibodies, Srikanth Singamaneni, PhD, has an idea. He’s a professor of mechanical engineering and materials science at the McKelvey School of Engineering at Washington University in St. Louis. Singamaneni and his team found a way to replace that single penetrating and painful needle with this nearly pain-free microneedle patch. The patch is applied to the skin.

    “We are only sampling the dermal tissue underneath the epidermis layer,” said Singamaneni.

    Just beneath the epidermis layer is deep enough, especially with so many tiny needles.

    “We can have as many as we want but typically what we work with is around a 10×10 array, so altogether around 100 microneedles in one patch.”

    Despite the number of needles, he said the application is nearly pain-free.

    “You’re not really touching the sensory nerves, the pain nerves, so you don’t feel the pain because the needle never touches that.”

    Singamaneni explained how one day a doctor would not always need blood because biomarkers of disease are also in the liquid surrounding our cells.

    “Biomarkers that are present in blood are also present in the dermal interstitial fluid,” he said. “Sampling this dermal interstitial fluid is just as good as sampling blood, at least for most of the biomarkers.”

    However, the biomarkers of disease in the liquid are in low abundance of making it difficult to detect. But Singamaneni said his lab solved that problem with another innovation inspired by the COVID-19 pandemic. It’s a highly sensitive and highly accurate biosensor proven to detect low quantities of proteins related to various diseases.

    His lab’s biosensor is based on an ultrabright fluorescent nanoprobe, called plasmonic-fluor. Plasmonic-fluor effectively turns up the brightness of fluorescent labels used in a variety of biosensing and bioimaging methods.

    Plasmonic-fluor is composed of gold or silver nanoparticles that serve as beacons. Brighter beacons mean fewer captured proteins are needed to determine their presence.

    “All we are doing is replacing the current label with this brighter label so that you can detect at much lower concentrations and much quicker.”

    The process only takes minutes for rapid detection. This highly sensitive and accurate technology, with the added touch of microneedles to the skin, can become a low-cost product with more time and research.  A microneedle patch could be administered at home saving a patient a trip to the doctor’s office or hospital.

    “We want to be able to design patches tailored to the diagnosis of any disease. And people should be able to apply these at home,” said Singamaneni. “Apply on the skin. Apply pressure, gentle pressure on it. Leave it there for maybe five to 10 minutes, a specified duration of time. Peel off the patch, put it in the mail and send it to a clinic where it gets analyzed and the results are communicated to the doctor and the patient so that subsequent actions can be taken.”