The real-time detection of chemical species in the body is of great interest in the diagnosis and treatment of disease. Examples include understanding inflammation in the body, which can be determined through the detection of cytokines; and understanding metabolic dysfunction, which can be determined through the detection of intramuscular oxygen and oxygen uptake under stressed and non-stressed conditions. We will discuss two microelectromechanical systems (MEMS)-based sensors for the detection of these biomarkers. The first device is a microwell-based impedance sensor for label-free, rapid sample-to-answer, real-time and in vivo cytokine detection. A functionalized microwell array is realized on the tip of a microneedle. The microwell array enhances the sensitivity of the sensor, while the microneedle form factor enables use in transcutaneous or transvascular sensing applications. The second device is a microfabricated noble metal electrode Clark-type oxygen sensor. Such devices are highly relevant in this application, since oxygen-based cues can be used to assess a wide range of in vivo biological effects. A low profile oxygen sensor operating in the diffusion limited regime allows not only for minimally invasive insertion, but also for oxygen sensing in the body without the need for a traditional electrochemical reference. The fabrication, testing, and use of these devices to predict mitochondrial dysfunction in vivo will be discussed. The presentation will also discuss commercialization of MEMS-based biomedical sensors, illustrated by two commercialized devices from our laboratory: a wireless permanently implantable hemodynamic monitor for monitoring of patients with congestive heart failure; and an in vitro interface to electrogenic cells for drug screening and scientific investigation.
Mark G. Allen received the B.A. degree in chemistry, the B.S.E. degree in chemical engineering, and the B.S.E. degree in electrical engineering from the University of Pennsylvania, Philadelphia, and the S.M. and Ph.D. degrees from Massachusetts Institute of Technology, Cambridge. In 1989 he joined the faculty of the School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, ultimately holding the rank of Regents’ Professor and the J.M. Pettit Professorship in Microelectronics, as well as a joint appointment in the School of Chemical and Biomolecular Engineering. In 2013 he left Georgia Tech to become the Alfred Fitler Moore Professor of Electrical and Systems Engineering and Scientific Director of the Singh Nanotechnology Center at the University of Pennsylvania. His research interests are in the development and the application of new micro- and nanofabrication technologies, as well as MEMS. Dr. Allen has held the posts of Editor-in-Chief of the Journal of Micromechanics and Microengineering, co-chair of the 1996 IEEE MEMS Conference, co-chair of the 2012 Power MEMS conference, chair of the 2016 Solid State Sensors Conference (‘Hilton Head’), and chair of the 2021 PwrSoC conference. He is co-founder of multiple MEMS companies, including Cardiomems, Axion Biosystems, and EnaChip. Professor Allen received the IEEE 2016 Daniel P. Noble Award for contributions to research and development, clinical translation, and commercialization of biomedical microsystems. He is a Fellow of the IEEE, and a Fellow of the National Academy of Inventors.