A team of engineers at the Massachusetts Institute of Technology (MIT), led by Rwandan professor Aristide Gumyusenge, has developed new organic substances that can efficiently convert signals from biological tissue into electronic signals used in transistors. Currently, the smart electronics that integrate with the human body work by converting ionic-based signals of biological tissue into electron-based signals. However, the materials used in such devices often maximize ion uptake, while sacrificing electronic performance. To remedy this, the MIT researchers developed new materials called organic mixed ionic-electronic conductors (OMIECs), which bring the ionic and electronic capabilities of smart devices into balance. According to Gumyusenge, these optimized OMIECs can even learn and retain these signals in a way that mimics biological neurons. “This behavior is key to next-generation biology-inspired electronics and body-machine interfaces, where our artificial components must speak the same language as the natural ones for a seamless integration,” he said. Gumyusenge and his colleagues published their results in the “Rising Stars” series of the journal Small. His co-authors include Sanket Samal, an MIT post-doctorate fellow; Heejung Roh and Camille E. Cunin, both MIT PhD students; and Geon Gug Yang, a visiting PhD student from the Korea Advanced Institute of Science and Technology. Since electronics that interface directly with the human body need to be made from lightweight, flexible and biologically compatible electronics, organic materials like OMIECs, which can transport both ions and electrons, make excellent building blocks for the transistors in these devices. “However, ionic and electronic conductivities have opposite trends,” Gumyusenge explained. “That is, improving ion uptake usually implies sacrificing electronic mobility,” he added. The MIT researchers’ design strategy makes it possible to tune the ability of an OMIEC to receive and hold on to an ion-based electrochemical charge, a process that resembles what happens with biological neurons, which use ions to communicate during learning and memory. This made Gumyusenge’s team wonder: Could their OMIECs be used in devices that mimic the connections between neurons in the brain? With this, the researchers said that someday this kind of technology could make the integration of electronics and biology even more powerful. For instance, Gumyusenge says, such materials are promising candidates toward the development of feedback systems which could do things like monitor a person’s insulin levels and automatically deliver the correct dose of insulin based on these data. Who is Gumyusenge Gumyusenge, 31, was appointed Assistant Professor of Materials Science and Engineering at MIT in 2021. He is a researcher and materials science engineer with a background in polymer chemistry, having obtained his PhD in chemistry with focus on organic semiconductors from Purdue University in 2019. His research interests are in the design and processing of novel organic materials for bioelectronics and neuromorphic computing devices. Born on a small farm in Kamonyi District, Southern Province, his family survived the 1994 Genocide against the Tutsi. Against all odds, he was a straight-A student right from primary level. He studied from schools including Petit Seminaire St Leon in Kabgayi where he majored in Chemistry, Biology, and Mathematics and scored distinctions in all subjects in the national exams at the end of high school in 2010. He especially scored the second-best score in chemistry, which earned him the Rwandan Presidential Scholarship to attend university in the USA.
