A serendipitous discovery by a team from Rice University, University of Cambridge and Stanford University has enhanced the stability of PEDOT:PSS, a vital bioelectronic material used in medical implants, computing and biosensors, potentially revolutionizing these fields.
A fortuitous discovery has led scientists from Rice University, the University of Cambridge and Stanford University to simplify the production of PEDOT:PSS, a composite material crucial to medical research, computing and bioelectronic devices.
For over 20 years, scientists have relied on a chemical crosslinker to stabilize PEDOT:PSS — a blend of two polymers — making it suitable for advanced applications.
However, Siddharth Doshi, a Stanford doctoral student and co-first author of the study, discovered that omitting the crosslinker and instead using higher temperatures produced a stable material unexpectedly.
“It was more of a serendipitous discovery because Siddharth was trying out processes very different to the standard recipe, but the samples still turned out fine,” co-corresponding author Scott Keene, a materials scientist from Rice University, said in a news release. “We were like, ‘Wait! Really?’ This prompted us to look into why and how this worked.”
The researchers found that heating PEDOT:PSS beyond its usual threshold stabilized it without the crosslinker and improved the material’s quality. This breakthrough could simplify the manufacturing of neural implants, biosensors and next-generation computing systems, enhancing reliability and efficiency.
PEDOT:PSS conducts both electronic and ionic charges, a feature that bridges the gap between biological tissue and technological devices.
“It allows you to essentially talk the language of the brain,” added Keene, emphasizing its importance for neurotechnology.
Eliminating the crosslinker not only streamlines the fabrication process but also enhances performance. The new method results in material with three times higher electrical conductivity and better stability, which is vital for medical applications where consistency is crucial.
The crosslinker previously used created an interconnected mesh, leaving some water-soluble strands exposed, causing stability issues and potential toxicity. Conversely, higher temperatures reorganize the polymer internally, enhancing stability without harmful chemicals.
“This method pretty much simplifies a lot of these problems that people have working with PEDOT:PSS,” Keene added. “It also essentially eliminates a potentially toxic chemical.”
Margaux Forner, a doctoral student at Cambridge and co-first author of the study, highlighted the improved fabrication and reliability of heat-treated devices such as transistors and spinal cord stimulators.
“The devices made from heat-treated PEDOT:PSS proved to be robust in chronic in vivo experiments, maintaining stability for over 20 days post-implantation,” Forner said in the news release.
The method also maintained excellent electrical performance when the material was stretched, showcasing potential for durable bioelectronic devices.
The research may also clarify previous stability issues in long-term neural implants, potentially enhancing neurotechnology for restoring movement after spinal cord injuries or improving brain-device interfaces.
Additionally, the team has developed a way to pattern PEDOT:PSS into microscopic 3D structures using a high-precision femtosecond laser. This advancement could improve how bioelectronic devices interact with cells, enhancing integration and longevity.
“We are really excited about the ability to 3D-print the polymers at the microscale,” Doshi added.
This capability could transform the fabrication of neural interfaces, promoting better tissue integration.
Keene also explored the material’s potential in neuromorphic memory devices, which emulate brain-like learning processes. This research could accelerate advancements in artificial intelligence.
The research from Rice University, Cambridge and Stanford could revolutionize the future of bioelectronics, making them safer and more effective.
Source: Rice University