The importance of the constructal framework in understanding and eventually replicating structure in tissue: comment on "The constructal law and the evolution of design in nature" by Adrian Bejan and Sylvie Lorente.

Abstract

One of the most promising techniques in regenerative medicine is the controlled growth of living and functioning tissue in the lab and the implantation of such material in a diseased organ. Actually, many of the most common medical conditions involve exactly the degeneration or reduction in numbers of cellular populations, with a corresponding inability of the body to replenish these populations and recover functionality. From chronic conditions (like ischemic myocardial heart disease) to incidental damage (like spinal cord injury), the possibility to implant successfully adequately large and appropriately functional tissue seems like a much desired option, and very substantial progress has been made in this direction [5]. The main reason we cannot culture substantially large tissue elements in vitro yet is the inability of prevailing physical transport mechanisms to supply nutrients and oxygen to the cells that are located in the core of such cultured samples, i.e., cells that are away from the surface: Diffusion, an omnipresent and metabolically cost-free mechanism has a limited effective range. Nature has solved this problem by utilising a finely balanced convection–diffusion duality, the specifics, origin and details of which are described nicely by the constructal law [1]. In effect, rapid transport networks (arteries) allow for distributing material efficiently to the smaller scales, where diffusion is effective and takes over. The constructal theory shows where the threshold for each process lies, in each system, [3]. It is this combination exactly, in ratios that evolution has optimised (and the constructal law sheds light on), that makes multicellular life possible. We believe that, having such a powerful explanative tool as the constructal law opens great vistas for going beyond observation and towards design. The multifaceted processes that marry transport with biology [2] can now be viewed in a different, fully rational, light and the great questions of morphogenesis [6] can be explored not only as a phenomenon that happens but also as a process that can be replicated. The main point the author would like to convey in this short Comment is that progress achieved to-date in tissue engineering laboratory techniques, as far as vascularisation is concerned and beyond, [4], can be harvested in a novel way by incorporating the first principles approach that the constructal law conveys. We can now think, for the first time, in terms of actively encouraging tree-like vascular growth in the right proportions and dimensions of each

DOI: 10.1016/j.plrev.2011.07.007

Cite this paper

@article{Ventikos2011TheIO, title={The importance of the constructal framework in understanding and eventually replicating structure in tissue: comment on "The constructal law and the evolution of design in nature" by Adrian Bejan and Sylvie Lorente.}, author={Yiannis Ventikos}, journal={Physics of life reviews}, year={2011}, volume={8 3}, pages={241-2; discussion 261-3} }