About Tissue Engineering
The concept of engineering tissues was introduced by Yuan-Cheng Fung of the University of California at San Diego in 1985, who also coined the term “tissue engineering”. At the same time, Robert Langer (Chemical Engineering, MIT) and Joseph P. Vacanti (Harvard Medical School) succeeded to culture cells in three dimensions, 3D, using porous polymeric materials (scaffolds) as cell substrates. In this way, 3D cellular constructs were formed that could be used to replace diseased or damaged tissues in patients solving the problem of shortage of donated organs for transplantation. However, this superficial geometrical similarity of bio-artificial tissues with the real ones, was not sufficient for their functionality and clinical translation proved to be difficult.
A new paradigm, named “developmental engineering”, has emerged recently. Besides the 3D cell growth and differentiation, the new paradigm considers as important the cell interactions that make a cell construct an integral entity with robust structure that resists environmental noise, called “developmental module”. Embryologists had since long observed that some parts of developing organisms, such as limb buds or tooth germs, are robust embryonic regions which are autonomous in their development and they can either develop ectopically. According to the new paradigm, the goal of tissue engineering is not to directly fabricate final tissue forms. Instead, the goal is the design of in vivo-like (biomimetic) in vitro processes, assembled from sequential subprocesses (unit operations) that correspond to in vivo developmental stages, that follow a gradual and concerted progression of tissue size and cell differentiation which preserves the cell interactions that lead to the organization of cells into intermediate in development tissue forms with modular-robust behavior. Such developmental modules can be then assembled with cells or other modules to form more complex tissues. Modularity therefore plays the same role in developmental processes as thermodynamics in physicochemical processes and renders biomimetic processes the only feasible ones that assure the process stability and product properties reproducibility.
The new paradigm of developmental engineering offers unique opportunities to tissue engineers to pursue together with developmental biologists the goal of elucidating the principles or laws of development. Developmental modules are dissipative structures that retain their organization secreting entropy to their environment. The connection of the macroscopically observed biological functions involved in energy dissipation in developmental modules with the topology of underlying modular gene/protein interaction networks is a new promising research direction that could lead to the expression of the developmental processes in terms of physical laws. If such laws or principles are discovered, they will place tissue engineering on a strong theoretical basis as the other engineering fields. This, in turn, will make scientifically concrete what is possible to be made in vitro which remains until now speculative with a high cost in terms of patients expectations as unfortunately the until now history of tissue engineering has shown.
About Speaker
Dr. Petros Lenas received his Ph.D in Biochemical Engineering from the University of Patras, GREECE. After more than 25 years of research experiences in universities and companies, such as New Jersey Institute of Technology(USA), Nagoya University(Japan), National Research Council of Canada(Canada), University Complutense of Madrid (Spain), Future Health Technologies(Belgium), Stem Cell Technology(Belgium) , he joined Harbin Institute of Technology, Shenzhen in 2016. His research interests are Tissue Engineering, Regenerative Medicine, Biomedical Engineering, Complex Systems, Developmental Biology. He searches for the principles or laws that nature uses to make tissues and organs and use them to make bio-artificial analogues for transplantations.
