New insights into the dynamics of self-assembling materials
Nature uses self-assembly to build molecular materials, such as cellular protein filaments, or microtubule that adapt and respond dynamically to specific stimuli such as temperature changes and chemical signals. Building synthetic self-assembling materials that possess similar properties could hold huge promise for a range of technological applications.
Molecular self-assembly and supramolecular structures
The DYNAPOL project, supported by the European Research Council(opens in new window), set out to investigate the molecular mechanisms that control the properties of dynamical self-assembling materials, a first key step towards the design of new types of materials for various applications. Self-assembly involves designing smaller units that in given conditions recognise each other, connect and grow. An intriguing feature that emerges when such self-assembling processes occur in certain environments and conditions is that the obtained materials exist in an intrinsically dynamic state. “It’s a little like playing with Lego… but one should imagine Lego bricks that can self-organise and reconfigure autonomously,” says DYNAPOL project coordinator Giovanni Pavan from the Polytechnic University of Turin(opens in new window) in Italy. “Materials made in such a way may possess intriguing properties, such as responsive behaviours, adaptivity and recyclability (just like with Lego, you can break self-assembled structures down to their constituent parts).”
Focus on dynamics
In the DYNAPOL project, Pavan wanted to focus on the importance of dynamics in self-assembling structures. “In the field, it is known that dynamics is fundamental to the properties of supramolecular materials,” he adds. “However, I felt that a real understanding of the factors controlling such dynamics was still missing.” The idea of the project therefore was to simulate not just structures or self-assembly processes, but rather the dynamic transitions and communication that goes on between self-assembling materials at the molecular level. A key challenge here was maintaining the resolution needed to see what is going on at the molecular and even sub-molecular level while studying supramolecular dynamics of these systems. In DYNAPOL, a range of tools, including multiscale modelling, advanced simulations, machine learning and software development were applied to study a variety of self-assembling systems. New methods and tools were also developed to detect fluctuations in any type of dynamically self-assembling materials, and to use the data to learn about the molecular factors that control their dynamical bioinspired properties.
New materials for various applications
A major outcome of DYNAPOL was to show how dynamical self-assembling systems behave like complex systems. “This means that properties emerge within them that cannot be easily attributed to the properties of the fundamental units, but rather to the molecular communications and disorder that dynamically fluctuate in them,” Pavan explains. The project has been hugely influential on the materials science field, with over 60 scientific papers published in important journals. The results also have potential for real-life applications. Fields where dynamics are central – ranging from batteries and imaging to drug delivery and adaptive materials – are looking into the possibilities that can be attained with new types of materials. “Imagine, for example, a medical cream, or an emulsion, that you apply to your skin,” says Pavan, “composed of self-assembled particles containing drugs that can autonomously bind and scan surfaces, looking for overexpression of specific receptors (or targets) and only releasing drugs where and when they are needed. “This is what our immune system naturally does. We can take inspiration from nature and learn how to use self-assembly to build something intelligent based on new types of dynamical materials.”
