The study by Dion Khodagholy, assistant professor of Electrical Engineering at Columbia University (CU), was originally published in Science Advances on the 24th of April. It follows Khodagholy’s research, which was carried out in collaboration with CU’s neurology assistant professor Jennifer N. Gelinas, and published in Nature Materials (which you can read about on All About Circuits).
While the latter paper focuses mainly on transistor technology (namely what the researchers have named ‘e-IGTs’, or enhancement-mode, internal ion-gated organic electrochemical transistors), the study in question is more concerned with the materials science of MCP: mixed-conducting particulate composite material.
Nevertheless, both studies collectively form a breakthrough in bioelectronics, which (as defined further in the above-linked AAC article), is the hybrid field of ‘biology’ and ‘electronics’. It encompasses electronic devices that can not only endure being in the user’s body, but also record and process some of that person’s biological information (meaning such bioelectronics R&D is vital to implantable tech).
The MCP Research: Aims and Achievements
As the CU researchers’ abstract in Science Advances explains: “Bioelectronics should optimally merge a soft, biocompatible tissue interface … for local, advanced signal processing”. What’s more, bioelectronics should also facilitate the bonding of soft and rigid electronics.
The need for a seamless integration of components is one of the main reasons that the scientists have developed their mixed-conducting particulate composite material.
While traditional electronics require several layers and materials to be rendered biocompatible (and even then, they may still require encapsulation to function in the body), Columbia University’s MCP solution, inspired by electrically-active cells, is organic in form and fabricated following the bonding of soft materials, biological tissue, and rigid electronics.
A close-up example of the Columbia's University's biocompatible MCP (mixed-conducting particular composite material) film sits on a user’s skin. Image Credit: Science Advances.
Developing Bioelectronic Devices
Particularly, the above innovation was carried out in the interest of achieving non-invasive, medical implantable, technology. The applications of such medtech are chiefly concerned with recording the implant carrier’s (i.e. the user’s) muscle action potentials for the implant carrier’s diagnostics and/or therapy. The MCP helps to facilitate bioelectronic devices that “interface effectively and safely with human tissue, while [being] capable of performing complex processing”, write the CU researchers on the study’s Columbia Engineering page.
The study’s said collaborator, the assistant professor Gelinas (MD, PhD), says that the smart composite material is able to reduce surgical complications due to its ability to record neurophysiological data with a “substantially reduce[d] footprint” when compared to the traditional use of neural interface devices. And the reason for such efficiency in the development and application of MCP boils down to the use of organic materials.
The Use of Organic Materials
Naturally, a key element of implementing practical biocompatible devices requires components that are not only flexible and chemically inactive—but also both unaffected by and non-hazardous to the human body (particularly its ionic cells).
Therefore, the CU researchers took stock of the current problems raised by traditional implantable tech components and focused on using organic materials instead. “[C]onducting and semiconducting organics,” write the researchers, “can form nonlinear electronic components (such as transistors and diodes) capable of biological signal sensing and transduction.”
(More information on CU’s use of biocompatible components, particularly transistors, can be read in the university’s aforementioned Nature Materials paper.)
Ultimately, the benefit of Columbia University’s organic MCP technology is two-fold: it both enables more biocompatible implantable medtech and also shows promise for the future of bioelectronics manufacturing itself. They are, as Gelinas says, “inexpensive and easily accessible to materials scientists and engineers”—and “form the foundation for fully implantable biocompatible devices ... to benefit health”.