Soft matter and biological physics are closely related branches of physics that strive to discover and apply fundamental principles that explain how macroscopic properties of natural and artificial materials and of living organisms arise from their many components. These two areas of physics differ from other areas of physics like condensed matter physics ("hard" matter physics) by being especially interested in room-temperature non-quantum phenomena that span multiple length and time scales, and that arise specifically from the inhomogeneity of their components. Examples of soft matter are liquids, liquid crystals, polymers, gels, foams and granular materials. Many parts of biological cells and tissues consist of soft matter systems but biological physics has two additional scientific challenges, one related to the fact that living systems are sustained nonequilibrium systems, and one to the goal of relating physical properties to biological function. Duke has a broad research program in this field, dramatically bolstered by the addition of three senior hires in the last year. This provides tremendous opportunities for strengthening the broader scientific stature and profile of the physical and biomedical sciences. In addition, the department benefits from the university-wide Center for Nonlinear and Complex Systems, the Quantitative Initiative, the Duke Institute for Brain Sciences, the our Duke Center for Soft Matter and the Materials Initiative, all joint efforts between departments in Trinity, Pratt and Medicine.
Condensed matter physics is subdivided into hard matter and soft matter. Soft matter comprises many-body systems that can be described by classical physics. The interplay between mechanical properties and thermal energies in soft systems produce complex phenomena that require new ways of thinking and modeling. In some classes of soft matter, thermal energies at ambient temperatures cause significant strains and stresses. Biological materials largely fall into this category. Biological physics also tackles the questions of non-equilibrium dynamics and spontaneous self-assembly of functional materials as well as complex information processing in neuronal and biochemical networks. Soft matter and biological physics research draws on classical branches of physics, quantum and classical mechanics, fluid mechanics, condensed matter and statistical physics, and optics. It depends on insights from biology, chemistry, mathematics, and engineering. Examples of research foci are:
- Proteins that play key biochemical roles, but are also important materials in cells and tissues. Insights from colloidal self-assembly help to understand the formation of amorphous, fibrillar and crystalline aggregates.
- Functional tissues, such as heart muscle, where cells self-organize into highly ordered structures and dynamic patterns. An important motivation for understanding this self-organization is the effort to construct tissue-engineered repair patches for infarcted heart areas.
- Brain function, where physics has had a strong impact both through the development of novel imaging and of theoretical tools. Quantitative modeling provides insights into how the dynamics of large networks of neurons lead to behavior.
- Granular materials (such as sand), a peculiar form of matter, displaying characteristics of solids, fluids and gases. Their complex dynamics, which share common properties with glasses, foams, emulsions and colloids, are not completely understood. Apart from being at the core of a multi-billion dollar industry, granular dynamics is involved in migrating sand dunes, earthquakes, avalanches and mudslides, geological erosion patterns and river sediments.
Immense complexity is the hallmark of living systems and of natural and technical soft materials. What is largely lacking is a quantitative description of heterogeneous, hierarchical, non-equilibrium soft materials in living systems, but that also hold large promise for technical soft materials of the future. Crucial for the dynamic control of systems are communication networks, such as the gene regulatory networks that control cell fate, or the functions of the brain and its computational analogues. Materials of the future will profit from the understanding of their biological counterparts.
Researchers in the Duke University Physics Department are active in three overlapping subfields of soft matter and biological physics: (i) granular, colloidal systems, glasses and polymers, (ii) biological physics, non-equilibrium cellular and tissue mechanics, and (iii) neurobiophysics. While experimental approaches vary, all subfields speak the common language of statistical and condensed matter physics. This research calls for collaboration across the disciplines, with Chemistry, Biology and Mathematics in Trinity, MEMS and BME in Pratt, and Biochemistry and Neuroscience at the School of Medicine.
Duke’s compact, interdisciplinary research campus offers unique opportunities to push the boundaries of physics and transfer tools and concepts into engineering, the life sciences and medicine. Physics takes part in ongoing campus-wide initiatives: Duke’s Center for Nonlinear Systems, the Quantitative Initiative, and the Duke Institute for Brain Sciences. A new university-wide facility for Advanced Light Imaging and Spectroscopy (ALIS@Duke) will assemble cutting-edge facilities for applications in (bio)materials science. New initiatives with Physics participation are the Materials Initiative and the Duke Center for Soft Matter.