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UD researchers Joel Schneider (foreground, left) and Darrin Pochan (foreground, right) with student researchers (left to right) Matthew Lamm, Juliana Kretsinger, Lisa Pakstis, Karthikan Rajagopal, Lisa Haines and Bulent Ozbas.

An interdisciplinary University of Delaware research team has made an important breakthrough in the design of environmentally responsive materials. Specifically, responsive hydrogels have been constructed from self-assembling peptides that could have far-reaching implications for the creation of innovative biomaterials.

The team, which is led by Joel Schneider, assistant professor of chemistry and biochemistry, and Darrin Pochan, assistant professor of materials science and engineering, has designed a hydrogel from a class of peptides that self-assemble into a desired material only after undergoing a molecular folding event, similar to the folding that is found in natural, biological proteins. The control and manipulation of this reversible folding event is what provides the environmental responsiveness in the final assembled hydrogel material.

Previously, most efforts in self-assembly had resulted in material structures that were static and not responsive to any external stimuli. Once self-assembly had been completed, the molecules were locked into a design that could not be altered. This is the first example of the use of small folding peptides to surpass the static quality of previous self-assembly systems.

The ability to manipulate the peptides in hydrogels is important in the creation of more complex biomaterials, including human tissue, through tissue engineering techniques. In addition, the fact that the underlying chemistry of the new materials is peptidic allows one to easily incorporate inherent biofunctionality and biocompatibility into the materials. Peptide bonds link the amino acids in natural proteins and peptides, which is a fundamental component of all living cells. This may provide a significant advantage over the design of biomaterials from more traditional petroleum-based polymers.

Both scientists said they believe the finding is unique. “This is the first example of taking advantage of a peptide folding event in the construction of a self-assembled material, specifically hydrogel scaffolding,” Pochan said.

“We have self-assembly and reversibility,” Schneider added.

Their work was reported in the Journal of the American Chemical Society.

Both scientists said the result would have been difficult to achieve without interdisciplinary research, an area in which UD is in the vanguard.

The research groups have been working together for about one and a half years toward a common end–the design and synthesis of peptides, simple biomolecules that can be used to construct advanced materials.

Schneider and his team have expertise in the design and synthesis of peptides as hydrogels.

Pochan and his team then take the hydrogels and treat them in various ways to see how they react and change in structure. Based on all of the experimental findings and fundamental, theoretical molecular modeling, Pochan and Schneider engineer new molecules leading to new materials.

By working together, the teams get a broader perspective, Schneider said, adding that the approach provides an expertise and energy that leads to more creative chemistry.

“Both areas are vital in research in a new and emerging field,” Pochan said. “We believe collaboration of this sort will be at the forefront of the development of new materials.”

Schneider said the interdisciplinary approach has been of great value to graduate students working on both teams. “Pochan’s materials science and engineering students are learning peptide design, and my chemistry and biochemistry students are learning microscopies and rheological-based experiments,” he said. “These are techniques they would not learn in the respective departments. You don’t find this level of collaboration on all campuses.”

Research on the project will continue in two basic areas, fundamental and technological.

The fundamental research will involve a more intense study of molecular design to better understand the self-assembly and reversibility process.

The technological research will be to determine potential uses for the materials as hydrogels, the building block in tissue engineering scaffolds.

The teams also will be investigating other molecular designs and possible new avenues in protein folding.

In addition to crossing departmental lines, the collaborative effort also involves two colleges, the College of Arts and Science, home of the Department of Chemistry and Biochemistry, and the College of Engineering, home of the Department of Materials Science and Engineering.

In addition, the research groups are affiliated with the Delaware Biotechnology Institute.

The research is funded as part of a multi-investigator $9.7 million grant from the National Institutes of Health through the Center of Biomedical Research Excellence (COBRE) program.

Contact: Neil Thomas, (302) 831-6408
Feb. 27, 2003