Biomimicry in biomedical research

NEWS NEWS aND ViEWS Biomimicry (literally defined as the imitation of life or nature) has sparked a variety of human innovations and inspired countless cutting-edge designs. From spider silk-made artificial skin to lotus leaf-inspired self-cleaning materials , biomimicry endeavors to solve human problems. Biomimetic approaches have contributed significantly to advances biomedical research during recent years. Using polyacryl-amide gels to mimic the elastic modulus of different biological tissues, Disher's lab has directed meschymal stem cell differentiation into specific lineages. 1 They have shown that soft substrates mimicking the elastic modulus of brain tissues (0.1−1 kPa) were neurogenic, substrates of intermediate elastic modulus mimicking muscle (8−17 kPa) were myogenic, and substrates with bone-like elastic modulus (25−40 kPa) were osteogenic. This work represents a novel way to regulate the fate of stem cells and exerts profound influence on stem cell research. Biomimcry also drives improvements in tissue engineering. Novel scaffolds have been designed to capture extracellular matrix-like structures, binding of ligands, sustained release of cytokines and mechanical properties intrinsic to specific tissues for tissue engineering applications. 2,3 For example, tissue engineering skin grafts have been designed to mimic the cell composition and layered structure of native skin. 4 Similarly, in the field of regenerative medicine, researchers aim to create biomimetic scaffolds to mimic the properties of a native stem cell environment (niche) to dynamically interact with the entrapped stem cells and direct their response. 5 Biomimicry can be achieved at different levels: mimicking nature form or function, mimicking natural processes and mimicking natural systems. 6 Mimicking form or function are the most common biomimetics seen in biomedical research. a recent example can be drawn from cardiac research, where the field is poised for new breakthroughs. Published in Biomaterials, Dr Parker's group used micropatterned surfaces to build 2-dimensional engineered cardiac muscle from neo-natal rat ventricular myocytes with distinct architectures that mimic in vivo hierarchal structures and electromechanical function of heart. 7 They combined image analysis of sar-comere orientation with muscular thin film contractile force assays to calculate the peak sarcomere-generated stress as a function of tissue architecture. Their data showed that increasing peak systolic stress in engineered cardiac tissues corresponds with increasing sarcomere alignment. Their results demonstrated that heterogeneities encoded in the extracellular space can regulate muscle tissue function, and that structural organization and cytoskeletal alignment are critically important for maximizing peak force generation. Their work suggested that engineering the extracel-lular space is an …