Bio & Medicine

Memorable intelligent membranes for future smart filters

The “intelligent” membranes created by researchers at the National Graphene Institute (NGI) have “memory” that can be used in smart separation technology, wound management, drug delivery, sensors, and memory devices.

According to Carlsberg/Royal Academy of Engineering Research Chair and study team leader Professor Rahul Raveendran Nair, “the history of membrane development spans more than 100 years and has led to a revolution in industrial separation processes.” Some work has been done in recent years to make membranes that look like biological structures, especially those that are “intelligent.”

Scientists now explain how they created intelligent membranes that can remember how permeable they were in the past and change their properties based on the environment in research that was published today in Nature. This indicates that the membranes are capable of adjusting to various conditions in their environment and, more importantly, of memorizing their state, which is a property that can be utilized in numerous applications.

“Membrane development has spanned more than a century and resulted in a revolution in industrial separation processes.” There has been some attempt in recent years to create membranes that replicate biological structures, particularly their’intelligent’ properties.”

Professor Rahul Raveendran Nair, Carlsberg/Royal Academy of Engineering Research Chair.

The most typical sign of intelligence or memory in a material is a phenomenon called hysteresis. It occurs when a system’s current properties are linked to and dependent on its previous state. Magnetic materials frequently exhibit hysteresis. A magnet, for instance, may have more than one possible magnetic moment in each magnetic field, depending on the magnetic field it was previously exposed to. Hysteresis is seldom seen, notwithstanding, in sub-atomic vehicles through counterfeit films.

“One of the greatest challenges we face on a global scale is coming up with simple, efficient solutions for clean water.” Professor Angelos Michaelides of the University of Cambridge said, “This study shows that fundamental molecular-level insights and nanoscale materials offer great potential for the development of “smart” membranes for water purification and other applications.”

Intelligent membranes based on MoS2, a two-dimensional material known as molybdenum disulfide, have been developed in this work by the Manchester team in collaboration with researchers from the University of Cambridge, Xiamen University, Dalian University of Technology, University of York, and National University of Singapore. These membranes can remember how permeable they were previously.

“The membranes mimic the function of biological cell membranes and display hysteretic ion and water transport behavior in response to the pH, which means they remember what pH they were exposed to before,” the researchers have demonstrated. “The membranes mimic the function of biological cell membranes and display hysteretic ion and water transport behavior in response to the pH.” ” Co-first author Dr. Amritroop Achari of the University of Manchester stated, “The memory effects we have seen are unique to these membranes and have never been observed in any inorganic membranes.”

The researchers showed that the biomimetic effect could be used to make autonomous wound infection detection better. They did this by placing the membranes in an artificial wound exudate that resembles the liquid that wounds produce and changing the pH of the exudate. The membranes allowed the wound exudate to only permeate at pH levels that are relevant to an infected wound, making them suitable for use as sensors for detecting infections. The new membranes can be used for a wide range of pH-dependent tasks, according to the researchers, including nanofiltration and mimicking neuronal cell function.

“The uniqueness of this membrane is that its hysteretic pH response can be seen as a memory function, which opens a lot of interesting avenues for the creation of smart membranes and other structures,” stated co-author Professor Kostya Novoselov, Langworthy Professor in the School of Physics and Astronomy at the University of Manchester and a professor at the Centre for Advanced 2D Materials, National University of Singapore. This kind of research has the potential to have a significant impact on the development of intelligent technologies for the future.”

More information: C. Y. Hu et al, pH-dependent water permeability switching and its memory in MoS2 membranes, Nature (2023). DOI: 10.1038/s41586-023-05849-4

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