Wearable Photonic Device for Multiple Biomarker Sampling and Detection without Blood Draws

Abstract Needle‐based blood draws or phlebotomy practice in clinics for centuries, often causing pain, discomfort, and inconvenience. Here, a wearable photonic device is presented by integrating a microlens array (MLA) and an optic microneedle array (OMNA) functionalized with immunobinding for safe and needle‐free biomarker sampling and detection. The MLA‐integrated OMNA amplifies and transmits LED light at 595 nm into skin through the OMNA, bypassing the light‐absorbing melanin in the epidermal layer, and evenly distributing it in the capillary‐enriched dermis independent of the skin colors. The 595 nm light is absorbed by hemoglobin (Hb) and oxygen‐Hb within the capillaries, triggering thermal dilation of capillaries without damaging them or causing petechiae. The light illumination remarkably increases in the concentrations of various blood biomarkers in the skin through biomarker extravasation. These biomarkers bound specifically to the capture antibodies on OMNA with each microneedle covalently immobilized with one specific antibody. The OMNA is extensively modified to amplify the immunobinding signals and achieve sensitivity superior to that of enzyme‐linked immunosorbent assay (ELISA) kits. As proof of concept, the functionality of the prototype for minimally invasive sampling and precise multiplexed blood biomarker detection in two mouse models is validated to quantify acute inflammation and specific antibody production.