A groundbreaking study published in Cell Reports Physical Science reveals the astonishing capacity of a simple hydrogel to master the iconic 1970s computer game ‘Pong.’ Dr. Yoshikatsu Hayashi and his team have demonstrated how this soft, flexible material, when connected to a computer simulation of the game through a custom multi-electrode array, showed remarkable improvement in its gameplay over time.
“Our research shows that even very simple materials can exhibit complex, adaptive behaviors typically associated with living systems or sophisticated AI,” said Dr. Hayashi, a biomedical engineer at the University of Reading‘s School of Biological Sciences. “This opens up exciting possibilities for developing new types of ‘smart’ materials that can learn and adapt to their environment.”
The hydrogel’s ability to learn is believed to stem from the movement of charged particles within the material in response to electrical stimulation, essentially creating a form of ‘memory’ within the hydrogel itself. This discovery may pave the way for revolutionary advances in the field of materials science and artificial intelligence.
“Ionic hydrogels can achieve the same kind of memory mechanics as more complex neural networks,” says first author and robotics engineer Vincent Strong of the University of Reading. “We showed that hydrogels are not only able to play Pong, they can actually get better at it over time.”
The researchers drew inspiration from a groundbreaking study that demonstrated how brain cells in a controlled environment could learn to play Pong through electrical stimulation and feedback.
“Our paper addresses the question of whether simple artificial systems can compute closed loops similar to the feedback loops that allow our brains to control our bodies,” said Dr Hayashi, a corresponding author of the study. “The basic principle in both neurons and hydrogels is that ion migration and distributions can work as a memory function which can correlate with sensory-motor loops in the Pong world. In neurons, ions run within the cells. In the gel, they run outside.”
Given that most current AI algorithms are rooted in neural networks, the researchers propose that hydrogels embody a distinct form of “intelligence” that could lead to the development of new and simplified algorithms. Moving forward, the researchers aim to delve deeper into the hydrogel’s “memory” by studying the mechanisms behind its memory and testing its capacity to undertake various tasks.
In an exciting breakthrough study recently published in the Proceedings of the National Academy of Sciences, Dr. Hayashi’s team, alongside Reading colleagues Dr. Zuowei Wang and Dr. Nandini Vasudevan, showcased a remarkable achievement. They successfully taught a hydrogel material to beat in sync with an external pacemaker, marking the first instance of this accomplishment using a non-living cellular material.
Their research demonstrated the extraordinary oscillation of the hydrogel material, both chemically and mechanically, mirroring the synchronized contractions of heart muscle cells. The team also provided a groundbreaking theoretical interpretation of these dynamic behaviors.
Moreover, the researchers discovered that by applying cyclic compressions to the gel, they could align its chemical oscillations with the mechanical rhythm. Even more astonishingly, the gel retained a memory of this entrained beating even after the mechanical pacemaker was removed. This discovery has the potential to revolutionize the field of biomedical engineering and open up new possibilities for artificial organ development and medical treatment.
“This is a significant step towards developing a model of cardiac muscle that might one day be used to study the interplay of mechanical and chemical signals in the human heart,” Dr Hayashi said. “It opens up exciting possibilities for replacing some animal experiments in cardiac research with these chemically-powered gel models.”
Dr. Tunde Geher-Herczegh, the lead author of the study, emphasized that these findings could revolutionize the way we investigate cardiac arrhythmia. This condition affects over 2 million people in the UK, causing the heart to beat too fast, too slow, or irregularly. These groundbreaking discoveries could pave the way for new insights and potentially life-saving interventions.
“An irregular heartbeat can be managed with drugs or an electrical pacemaker, but the complexity of biological heart cells makes it difficult to study the underlying mechanical systems, independently from the chemical and electrical systems in the heart,” she said. “Our findings could lead to new discoveries and potential treatments for arrhythmia and will contribute to our understanding of how artificial materials could be used in place of animals and biological tissues for research and treatments in the future.”
The research team’s groundbreaking findings are poised to revolutionize numerous fields, from soft robotics and prosthetics to environmental sensing and adaptive materials. With a focus on developing even more intricate behaviors, the potential real-world applications are tremendous. This includes creating alternative lab models to propel cardiac research forward while diminishing the necessity of animal testing in medical studies.
Journal reference:
- Vincent Strong, William Holderbaum, Yoshikatsu Hayashi. Electro-Active Polymer Hydrogels Exhibit Emergent Memory When Embodied in a Simulated Game-Environment. Cell Reports Physical Science, 2024; DOI: 10.1016/j.xcrp.2024.102151