Wearable Photonic Device for Multiple Biomarker Sampling and Detection Without Blood Draws
Blood draws or phlebotomy using needles have been practiced in clinics for several centuries and it often causes pain, discomfort, and inconvenience. Herein, we create a wearable photonic device by integrating a microlens array (MLA) and an optic microneedle array (OMNA) functionalized with immunobinding capacity for safe and needle-free biomarker sampling and detection. The MLA-integrated OMNA amplified and transmitted LED light at 595 nm into the skin through the OMNA, bypassing the light-absorbing melanin in the epidermal layer, and evenly distributing it in the capillary-enriched dermis. The 595 nm light was preferably absorbed by hemoglobin (Hb) and oxygen-Hb within the capillaries, triggering thermal dilation of capillaries without damaging them or causing petechiae. The light illumination resulted in remarkable increases in the concentrations of various blood biomarkers in the skin owing to capillary dilation and biomarker extravasation. These extravasated biomarkers bound specifically to the OMNA, which was covalently decorated with capture antibodies, each microneedle immobilized with one specific antibody. The multi-functional OMNA was extensively modified to amplify the immunobinding signals and achieve sensitivity superior to that of enzyme-linked immunosorbent assay (ELISA) kits. As a proof of concept, we validated the functionality of the prototype for minimally invasive sampling and precise multiplexed blood biomarker detection in two mouse models to quantify acute inflammation and specific antibody production. This cost-efficient device provides a promising platform for blood-free, multiplexed detection of blood biomarkers.