Research on self-assembling biomolecular materials is an exciting new discipline lying at the intersection of molecular biology, the physical sciences, and materials engineering. Biomolecular materials are those whose molecular-level properties are abstracted from biology. They are structured or processed in a way that is characteristic of biological materials, but they are not necessarily of biological origin. For example, the structure of a man-made ceramic material may be based on that of a clam shell, or a synthetic polymer may be produced using techniques from molecular biology that were originally developed for working with proteins. A key feature of biomolecular materials is their ability to undergo self-assembly, a process in which a complex hierarchical structure is established without external intervention. Self-assembly is common in biological materials. For example, long protein molecules fold themselves into complicated three-dimensional structures, and certain lipid molecules align themselves with each other to form membranes.
The focus of this report is the study and generalization of biomolecular self-assembly, with the ultimate goal being the development of new materials of technical importance. The underlying theme is the belief that there are important lessons to be learned from understanding, and perhaps mimicking, biological materials found in nature and the ways in which they self-assemble. In nature, experiments on biological materials have been ongoing for millions or even billions of years, and it is up to us to understand them better and learn how to profit from them.
If the principles of biomolecular self-assembly can be extended to the control of modern materials synthesis, they will lead to a broad range of new materials and processes with significant technological impact. The approaches used can be expected to fall into two general categories. The first involves directly mimicking biological systems or processes to produce materials with enhanced properties. An example of this approach is the use of molecular genetic techniques to produce polymers with unprecedentedly uniform molecular length. The second category involves studying how nature accomplishes a task, or how it creates a structure with unusual properties, and then applying similar techniques in a completely different context or using completely different materials. An example of this approach is the study of the laminated structure of clam shells, which has been reverse-engineered to design a metal ceramic composite twice as strong as other composites and an order of magnitude tougher, and constructed of more robust materials than its natural analogue. An important finding of this report is that successful application of biomolecular techniques could have a significant impact on materials and processes.
The Panel on Biomolecular Materials has identified a number of long-term scientific and technological opportunities in the field. Molecules that form liquid crystals can be incorporated into polymers to produce materials that have useful optical properties, are easily processed, and have good mechanical properties. Membrane-based structures can be used in applications ranging from controlled release of drugs to ultrafiltration to biosensors. It may be possible to design self-assembling electronic devices. New synthetic polymers and new polymer synthesis techniques are possible, including the production of protein-and polyester-based polymers from biomass. Biomolecular sensors may find applications in health care, agriculture, ensuring food quality and safety, and the detection of biological warfare agents. Biomotors may be developed that can construct biomolecular structures on a unit-by-unit basis.
The panel has concluded, however, that the existing infrastructure for research on biomolecular materials is not keeping pace with the development of these opportunities. As time passes, and as the record of significant results grows and the potential economic impact becomes more apparent, the need for new infrastructure only becomes more acute. The panel has therefore concluded that the existing system of disciplinary, individual-investigator-based excellence in research and education should be augmented.
Specifically, the panel has identified the following four options that could help to stimulate progress in the field:
- Interdisciplinary collaborations could be encouraged by a new mode of research through which small numbers of scientists would come together to work on a specific problem, such as the ones identified in this report. This mechanism would encourage new collaborations while keeping their size small to help ensure accountability.
- Consortia in biomolecular materials could be developed, i.e., groups of investigators that are focused on a specific theme or a specific instrumental capability. Such groups could involve scientists at a particular site such as a university campus or a government laboratory, or they could be consortia involving several sites. They would vary in size but would each have a well-defined focus: specific instruments, particular scientific problems, or a defined technological goal. Pre-existing collaborations with established track records of interdisciplinary activity should be favored in establishing these groups. Some of the groups could be built into existing structures such as the Materials Research Laboratories (MRLs), Science and Technology Centers (STCs), and government laboratories. Groups that have special facilities should be open to external scientists. Geographical dispersion could be a component in the selection criteria. Incorporation of the government laboratories into the groups should be strongly encouraged since the government laboratories house a broad spectrum of instruments, experience in instrument development, and relevant expertise in such areas as synchrotron radiation, neutrons, imaging (electron microscopy, scanning tunneling microscopy, atomic field microscopy, and x-ray microscopy), and chemical and biological synthesis and characterization.
- Academic programs could be established at universities to encourage curriculum development and training in biomolecular materials. These programs would bridge biology, materials science, and the physical sciences. The multidisciplinary character of biomolecular materials research, though in many ways a great strength, can be a barrier for students pursuing an education in the field. New academic programs and curriculum development could help to overcome this problem. It is important that students are trained in one of the disciplines in depth, however, obtaining interdisciplinary breadth during the research phase of their graduate careers.
One way to support such training could be the provision of special training grants like those that NIH has recently provided in areas related to biomaterials. Any such grants should include requirements for additional courses as well as for a program of research. The panel believes that the effectiveness of such a grant program would be enhanced if institutions receiving grants were encouraged to strengthen their ties with government and industrial laboratories. For example, they could make arrangements for outside laboratories to provide summer jobs for their graduate students, and the participating government and industrial researchers could host visitor programs and serve as guest lecturers at the universities receiving the grants.
- A national Biomolecular Materials Institute (BMI) could be established, located at a university or a government laboratory or another site with an appropriate intellectual environment. Like options 1 and 2 above, this option is motivated by the panel's consensus that interdisciplinary collaboration requires special support and encouragement. For example, in the study of many aspects of biomolecular materials, such as those described above for molecular machines, close interaction between researchers is both difficult and very important. In addition, a national institute would broaden access to instruments and research facilities, facilitate contacts between the academic community and private industry, and enhance the visibility of the field in a way that would encourage the creation of university programs in biomolecular materials research and education.
A national BMI would act as an umbrella organization for the field. It would have four main tasks:
- To examine research directions through workshops, meetings, and studies, giving particular attention to proposed novel initiatives;
- To encourage interdisciplinary collaborations by bringing together scientists and engineers from different backgrounds, e.g., different disciplines or affiliations;
- To provide instrumental facilities that would encourage interactions between experimental groups; and
- To provide industry with a single contact point for obtaining information about biomolecular research activities and for obtaining assistance in making connections with those activities.
Structurally, the BMI might resemble the NSF-sponsored Institute for Theoretical Physics in Santa Barbara. For example, it would have quasi-independent status and be overseen by a broad-based advisory board. It would consist of a small cadre of permanent scientists, plus staff commensurate with the above-listed tasks, such as experts to assist visiting scientists in using the instruments and laboratories. Funding should if possible be provided in at least five-year increments, either by a single agency or preferably by a consortium of agencies such as NSF, NIH, the Department of Energy, and the Department of Defense. Funding should also include substantial industrial support if at all possible, probably at about the 25% level.
Although this option may be difficult to achieve in the current funding environment, the panel believes it is an important goal for the future.