UC San Diego

Lab-Under-The-Skin based on a microneedle platform opens a new realm of possibilities that can shape the future of healthcare worldwide. From continuous monitoring to multiplexed measurements of numerous biochemical biomarkers, real-time measurements, remote monitoring/care, and actionable feedback to the wearer are parts of the possibilities to be realized in this realm. A microneedle-based wearable sensing platform is the closest system to realizing such a possibility in a pragmatically viable fashion. The pain-free, blood-free, minimally invasive microneedle tips gently access the revitalizing interstitial fluid (ISF) to initiate electrochemical transduction of the biochemical molecule of interest. Almost identically, ISF mimics the composition of the gold-standard blood, both chemically and temporally. ISF is considered the most reliable and clinically valid biosensing medium, especially in comparison to sweat, saliva, tear, urine, and stimulated ISF, and has a highly matured commercial and research track record.

The present thesis first, introduces the historical development of microneedle-based biosensors. Next, for the first time, it unravels the engineering and scientific fundamentals that make the idea of the "Lab-Under-The-Skin" a practical reality. The writing then elaborates on additional biochemical biomarkers of interest and their sensing mechanism when used in a microneedle-based form factor. Lastly, the thesis portrays the future of the microneedle-based wearable sensing field with an example from the cutting-edge electrochemical aptamer-based microneedle biosensing.