Plastic from plants? NSF grant helps OHIO researchers explore plant polymer scaffolding in search for fossil fuel replacements

In a world increasingly aware of the environmental impact of fossil fuels, researchers at Ohio University are embarking on a new venture to find sustainable alternatives for one of the most widely used materials: polymers. For decades, polymers have been a cornerstone of modern life, from everyday products to high-tech solutions in electronics, food, cosmetics and medicine. Yet most of these materials are derived from fossil fuel-based chemical feedstocks, which can pose a threat to the environment. As a result, scientists are seeking new, sustainable sources to create these essential materials.

Ohio University researchers Mick Held, Ph.D., and Katherine Cimatu, Ph.D., are working on a project to develop plant-based polymers through a multi-year National Science Foundation (NSF) grant. Held, an associate professor and graduate chair of the Molecular and Cellular Biology Program, and Cimatu, an associate professor, graduate chair and Roenigk Chair in Chemistry, are experts in chemistry, biochemistry and materials science; they have come together to investigate the polymerization of plant-based biopolymers known as extensins. These proteins are found in plant cell walls and are crucial for growth, defense and structure.

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"Mother nature is an extraordinary chemist," Held said, referring to the way plants, particularly their cell walls, are composed of biopolymers that are crucial for growth and structure. “Over 80% of the carbon fixed by plants during photosynthesis ends up in these complex molecules. As a renewable carbon source, plant cell walls represent a promising and sustainable feedstock for the development of new materials.”

One of the exciting aspects of this research is its interdisciplinary approach, combining expertise in different fields to tackle the complex problem.

"My background is in physical chemistry and materials science, while Mick’s expertise lies in biochemistry and molecular biology,” Cimatu explained. “Together, we bring two different areas of expertise to tackle this problem in a comprehensive way."

The team, which includes undergraduate and graduate students, is studying the self-assembly of extensin-inspired polymers using atomic force microscopy. This cutting-edge technique allows them to observe the molecular behavior of these biopolymers.

"These plant-based polymers self-assemble into lattice-like structures on their own, which is fascinating to study," Cimatu said. “We are investigating how different factors, such as pH and other conditions, can influence the assembly and properties of these polymers. By understanding these dynamics, we hope to create biopolymers that mimic the properties of natural extensins while offering new functionality for use in a range of applications—from biomedical uses, like wound healing, to food enhancements and electronics.”

By investigating the self-assembly process, the team hopes to uncover the biophysical properties of these polymers and understand how they can be manipulated to create new types of sustainable materials—potentially replacing petroleum-based polymers in various industries.

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In addition to the interdisciplinary approach from Held and Cimatu, the research team is also composed of several OHIO students ranging from undergraduates Jack Kenny and Gavin Mumma to graduate student Tharushi Ambagaspitiya to Ph.D. candidates in chemistry and biochemistry Abdul-Hakeem Al Bulushi and Allan K. Regunton. Each student is actively engaged in either conducting experiments, purifying proteins and/or analyzing results—all while gaining valuable experience in the lab.

Al Bulushi is working on expressing proteins related to the biopolymer research and has already made significant progress, generating valuable data from these proteins.

“The research starts with creating synthetic genes and selecting the optimal portions of DNA for their construction,” Al Bulushi said. “We then use plant cells to express the encoded proteins, which are then assembled on  highly ordered pyrolitic graphite (HOPG) surfaces.”

According to Al Bulushi, once the protein is expressed, it needs to be purified through several steps to ensure it is free of contaminants. After purification, the protein is analyzed for its amino acid composition and glycosylation (sugar attachments), which may affect its properties. This process is essential for understanding the protein’s behavior and how it can be used in biopolymer applications. After self-directed polymerization, the proteins can cross-link to form networks on the graphite surface. This cross-linking process is crucial because it locks the protein structures into fixed patterns. By controlling how these networks form, the team hopes to create new materials with specific properties.

“If we can control how these networks form, it will open up possibilities for creating new materials with unique characteristics,” Al Bulushi added. “By altering the conditions and the protein’s characteristics, we can explore different shapes and forms, such as branching patterns.”

Regunton is also working on synthesizing proteins found in plant cell walls, one of the most abundant natural resources on Earth.

“These proteins, known for their self-assembly capabilities, could revolutionize how we approach materials design,” Regunton said. “The research aims to understand how these proteins interact with each other to form structures that can be used in various industries, offering environmentally friendly alternatives to fossil fuel-derived materials.”

Both Ph.D. candidates are developing methods to control this process by modifying the proteins to see how they behave when assembled on surfaces. This includes understanding the protein assembly patterns and how to influence these patterns to create useful materials.

“The project not only promises to advance our understanding of plant biology but also holds the potential to provide new, sustainable materials that can address pressing environmental challenges,” Regunton said. “The research is poised to make significant strides in the field of biopolymers, paving the way for materials that are derived from nature, environmentally friendly and compatible with a wide range of industries.”

Ambagaspitiya is acquiring and analyzing images of self-assembled polymerization of extensins using atomic force microscopy (AFM). Once she receives the extensin glycoprotein monomer stock solutions from Held’s laboratory, she first makes the samples with necessary dilution, followed by depositing the solutions on ultraclean HOPG substrates. During incubation, the extensin monomers start polymerizing into networks.

“My goal is to use AFM and capture how this polymerization proceeds with respect to concentration, time, pH, and other parameters,” Ambagaspitiya said. “After acquiring the topographical images, I analyze the nature and extent of polymerization by determining the length, height and width of the polymer segments to evaluate the end-to-end, lateral and stacking self-assemblies.”

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The interdisciplinary approach between Held’s and Cimatu’s labs not only enhances the research but also serves as a valuable learning experience for the students involved. By working alongside scientists with different areas of expertise, the students gain firsthand experience in collaborative problem-solving. This environment teaches them how to approach challenges from multiple perspectives—whether it's through biochemistry, materials science or physical chemistry—showing them that even with different skill sets, all are united by the same goal. This collaborative atmosphere allows students to learn how to communicate across disciplines and leverage each other’s strengths to find more effective and holistic solutions.

“This was a great opportunity for me to experience working with native plant biopolymers, since I have only worked with synthetic polymers before,” Ambagaspitiya added. “Being a physical chemist, this project allowed me to widen my interest over to understanding self-assembly processes of biomolecules.”

The team’s research is currently focused on the genetic aspect of this process, with them developing and characterizing the genes needed to produce these biopolymers. Once the proteins are expressed and purified, they will be passed on to other researchers to advance the next phase of materials development.

“We want to train the next generation of scientists who are not only proficient in their research, but also able to think critically about how their work can have a broader impact on the world,” Held added.

This research lays the foundation for future advancements in the world of polymers, opening up new opportunities for sustainable materials that could revolutionize industries.

“The techniques we are developing and the knowledge we are gaining will open many doors for future research, allowing us to explore a wide range of plant-based proteins and biopolymers,” Cimatu added. “This project could ultimately change the way we think about materials and their impact on the planet.”