Fibrous networks of biopolymers are found in both the intracellular and extracellular matrix. From the microscopic scale of a single cell to the macroscopic scale of fibrous tissues, biopolymers with different stiffness control cellular processes such as cell differentiation, proliferation, transportation and communication. In recent years, a large number of different hydrogels has been developed, often with the goal to create an artificial extracellular matrix for biomedical applications. However, the mechanical environment inside and outside the cell is not determined by a single component. Multiple biopolymers with different structural and mechanical properties which physically interact with each other, make the mechanical environment of a cell in vivo much more complicated than the environment of a cell in a single-component artificial matrix.
The mechanics of natural biopolymer gels however, are very different from most synthetic hydrogels because they show strain stiffening behaviour. Reconstituted networks of cytoskeletal polymers such as actin or intermediate filaments or extracellular biopolymers such as collagen or fibrin show a large increase in stiffness upon an applied stress or deformation. The stiffening response prevents these networks from breaking under external stresses and also enables communication between cells growing in these materials. Recently a new biomimetic polymer hydrogel was developed with unique cytomimetic properties, based upon oligo(ethylene glycol) grafted polyisocyanopeptides. These extremely stiff helical polymers form gels upon warming at concentrations as low as 0.005 %-wt polymer, with materials properties almost identical to these of intermediate filaments and extracellular matrices. The unique ability of these materials and their application in cell growth and drug therapeutics revealed the importance of polymer stiffness and material non-linear mechanics.
How to control these nonlinear mechanical properties and how the stiffening response is affected by the composite nature of natural biopolymer networks such as the cytoskeleton or the extracellular matrix will be presented.
Professor Alan Rowan is performing his research at the interface of chemistry and biology with seminal and pioneering work on processive catalysis and functional self-assembly. His latest scientific achievement has been the development of the first truly biomimetic hydrogel which mimics the mechanic and functional properties of the extracellular membrane. This recent discovery has further established Professor Rowan as a truly innovative scientist, working toward understanding at the molecular level the functional of hierarchical materials and catalysis.
Professor Rowan has published nearly 300 hundred peer-reviewed articles and books (h-index 68), including 18 Science and Nature-family papers, that were cited more than 17,000 times (Google Scholar). His research has also led to several patents, with a variety of commercial applications. He has had the pleasure of supervising more than 55 PhD students who have received their doctoral degree.
Professor Rowan, is currently an ARC Laureate Fellow, Chair of the Scientific Advisory Board for the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and board member of: The UQ Confucius Institute, The Dow Centre for Sustainability, and of UQ Senior Management group.