Share your Science is the section where CENL-SWNL members disseminate the research that they do in The Netherlands. Today, Diego López Barreiro from Delft Biotechnology Center talks about the fascinating properties of bio-inspired materials and their interesting applications.
Diego López Barreiro studied chemical engineering at the University of Santiago de Compostela, followed by a PhD in Ghent (Belgium) in biorefineries. He is currently working as a post-doctoral researcher (Marie Curie fellowship) at Delft Biotechnology Center in The Netherlands. His research focuses on the development of bio-based materials and structural biopolymeric materials (particularly proteins), using experimental and computational methods.
Nature, our best inspiration to create sustainable materials
Lets start with a question for you: what do you think is the most technologically advanced material in this picture? Is it the laptop, the phone, the mouse, the camera or the headphones? Actually, none of those. In fact, the correct answer is the plant. Compared to the electronic devices in the image, the plant is a self-assembling, self-healing and self-replicating material. Moreover, it is renewable, capable of sensing its surroundings and responding to changes in the environment, and it can do so autonomously and without the need for electricity.
With this example we intend to show that nature is the best possible engineer, because it has had a head start of billions of years in the task of creating and optimizing an extraordinarily high number of elegant materials, with high performance, and simultaneously resistant and lightweight. The most astonishing thing about natural materials is that they manage to achieve these properties while forming under mild temperature and pressure conditions. This is in stark contrast to most man-made engineering materials, which require complex and often polluting chemical processes to be produced. Nature endows its materials with an elaborate structure, mostly made up of biopolymers (i.e., proteins or carbohydrates), and sometimes mixed with inorganic components (such as calcite or silica). And it does so by following instructions stored in the DNA of the cells that produce these materials. Under these austere conditions, nature manages to manufacture materials that allow stress distribution, crack deflection, or impacts shielding, and that combine two properties difficult to achieve in synthetic materials: bulk production and design with atomistic resolution.
One of the main examples of these biological materials is wood, which is one of the most used materials for building thanks to its combination of lightweight and mechanical resistance. Another example are mussels, which produce a protein glue that allows them to adhere to rocks on the coast, irregular surfaces that are continuously exposed to extreme conditions (wind, strong waves, or high salinity) that would represent a big challenge for any synthetic adhesive. Spider silk, skeletal bones, or mollusk shells are other examples of natural materials that often surpass by orders of magnitude the properties of synthetic materials made by humans. These and other examples fascinate many scientists and engineers, who in recent decades have been at the forefront of developing materials with structures inspired by natural materials, which is known as bio-inspired design. These materials have applications in fields such as biomedicine, energy storage, or infrastructure.
Structural proteins are especially promising for the development of new bio-inspired materials. Structural proteins provide a scaffold that serves as habitat or protection for living cells or organisms. Some examples of these proteins include silk, collagen, elastin, or keratin. The advantage of this type of proteins is that they are usually made up of highly repetitive units (small blocks of amino acids). These pieces can be used like Lego pieces and mixed in many ways in the laboratory, allowing the creation of new non-natural structural proteins that combine properties of different proteins, such as the toughness of silk and the elasticity of elastin. This is expanding our ability to produce new functional and complex materials, generally biocompatible and biodegradable. Once these new structural proteins have been designed, we can use biotechnological techniques to introduce the DNA with the instructions for their manufacture into bacteria, turning bacteria into micro-factories of these new structural proteins.
One downside to developing these proteins is how labor-intensive it is to create them in the laboratory. Fortunately, thanks to advances in analysis and simulation techniques, we are increasingly able to develop computer models that study and predict the properties of these new structural proteins. This makes it possible to select structural proteins with optimized properties, before even producing them experimentally in the laboratory. This, combined with continuous advances in materials manufacturing techniques (such as 3D printing) or advances in synthetic biology that allow the integration of materials and microorganisms with pre-programmed functions to create so-called living materials (such as self-healing cement) make this is a very promising field. A field of study with the ability to create materials in the coming decades at the intersection of biology, engineering and computing, which we are not even capable of imagining today.
Note: This article is part of the dissemination activities of the project “Structural proteins for biomedical materials”, funded by the Horizon 2020 framework program of the European Union, under the Marie Skłodowska-Curie Actions research and innovation program (grant number 892369) .