Bio-Imitation of Mexican Migration Routes to the USA with Slime Mould on 3D Terrains

Plasmodium of Physarum polycephalum (P. polycephalum) is a large single cell visible by an unaided eye. It shows sophisticated behavioural traits in foraging for nutrients and developing an optimal transport network of protoplasmic tubes spanning sources of nutrients. When placed in an environment with distributed sources of nutrients the cell ‘computes’ an optimal graph spanning the nutrients by growing a network of protoplasmic tubes. P. polycephalum imitates development of man-made transport networks of a country when configuration of nutrients represents major urban areas. We employed this feature of the slime mould to imitate mexican migration to USA. The Mexican migration to USA is the World's largest migration system. We bio-physically imitated the migration using slime mould P. polycephalum. In laboratory experiments with 3D Nylon terrains of USA we imitated development of migratory routes from Mexico-USA border to ten urban areas with high concentration of Mexican migrants. From results of laboratory experiments we extracted topologies of migratory routes, and highlighted a role of elevations in shaping the human movement networks.     

Study of the Geometry and Folding Pattern of Leaves of Mimosa pudica

Many structural and functional properties possessed by plants have great potentials to stimulate new concepts and inno-vative ideas in the field of biomimetic engineering. The key inputs from biology can be used for creation of efficient and op-timized structures. The study of the geometry and folding pattern of leaves of Mimosa pudica,referred as Sensitive Plant,reveals some of the peculiar characteristics during folding and unfolding. When the leaf is touched,it quickly folds its leaflets and pinnae and droops downward at the petiole attachment. With the help of experiments on simulation model,the variations in angle of leaflets and degree of compaction after folding are investigated.     

Characterization of thin gelatin hydrogel membranes with balloon properties for dynamic tissue engineering

Cell or tissue stretching and strain are present in any in vivo environment, but is difficult to reproduce in vitro. Here, we describe a simple method for casting a thin (about 500 μm) and soft (about 0.3 kPa) hydrogel of gelatin and a method for characterizing the mechanical properties of the hydrogel simply by changing pressure with a water column. The gelatin is crosslinked with mTransglutaminase and the area of the resulting hydrogel can be increased up 13-fold by increasing the radial water pressure. This is far beyond physiological stretches observed in vivo. Actuating the hydrogel with a radial force achieves both information about stiffness, stretchability, and contractability, which are relevant properties for tissue engineering purposes. Cells could be stretched and contracted using the gelatin membrane. Gelatin is a commonly used polymer for hydrogels in tissue engineering, and the discovered reversible stretching is particularly interesting for organ modeling applications.     

A biomimetic motility assay provides insight into the mechanism of actin-based motility

Abiomimetic motility assay is used to analyze the mechanism of force production by site-directed polymerization of actin. Polystyrene microspheres, functionalized in a controlled fashion by the N-WASP protein, the ubiquitous activator of Arp2/3 complex, undergo actin-based propulsion in a medium that consists of five pure proteins. We have analyzed the dependence of velocity on N-WASP surface density, on the concentration of capping protein, and on external force. Movement was not slowed down by increasing the diameter of the beads (0.2 to 3 microm) nor by increasing the viscosity of the medium by 10(5)-fold. This important result shows that forces due to actin polymerization are balanced by internal forces due to transient attachment of filament ends at the surface. These forces are greater than the viscous drag. Using Alexa488-labeled Arp2/3, we show that Arp2/3 is incorporated in the actin tail like G-actin by barbed end branching of filaments at the bead surface, not by side branching, and that filaments are more densely branched upon increasing gelsolin concentration. These data support models in which the rates of filament branching and capping control velocity, and autocatalytic branching of filament ends, rather than filament nucleation, occurs at the particle surface.     

Laying out ground rules for protein-aided nanofabrication: ZnO synthesis at 70°C as a case study

Designer proteins that incorporate solid-binding peptides hold promise to control the nucleation, growth, morphology, and assembly of inorganic phases under mild conditions of temperature and pressure. However, protein-aided nanofabrication remains more art than science and some materials can only be synthesized at temperatures that cause most mesophilic proteins to unfold. Using zinc oxide (ZnO) synthesis at 70°C as case study, we show here that seemingly unimportant variables, such as the carry-over concentration of Tris buffer and the "empty" host protein scaffold can exert a significant influence on materials morphology. We also show that, once well-controlled conditions are established, thermodynamic predictions and adsorption isotherms are powerful tools to understand how various ZnO-binding sequence inserted within the thermostable framework of Escherichia coli thioredoxin A (TrxA) affect inorganic morphogenesis.     

The structural basis of oscillation damping in plant stems - biomechanics and biomimetics

1 Introduction Dynamic wind loads can excite potentially de-structive oscillations in plants. Without dissipation ofmechanical energy a resonance catastrophe is likely tooccur in dynamic winds with frequency componentsclose to the resonant frequencies of the plant. Four modesof oscillation damping are considered [1] ? Friction with other members of the plant commu-nity as for instance in the dense stand of bamboos. ? Structural damping: other than in the engineeringscien…     

Bioinspiration as a method of problem‐based STEM education: A case study with a class structured around the COVID‐19 crisis

Bioinspiration is a promising lens for biology instruction as it allows the instructor to focus on current issues, such as the COVID‐19 pandemic. From social distancing to oxygen stress, organisms have been tackling pandemic‐related problems for millions of years. What can we learn from such diverse adaptations in our own applications? This review uses a seminar course on the COVID‐19 crisis to illustrate bioinspiration as an approach to teaching biology content. At the start of the class, students mind‐mapped the entire problem; this range of subproblems was used to structure the biology content throughout the entire class. Students came to individual classes with a brainstormed list of biological systems that could serve as inspiration for a particular problem (e.g., absorptive leaves in response to the problem of toilet paper shortages). After exploration of relevant biology content, discussion returned to the focal problem. Students dug deeper into the literature in a group project on mask design and biological systems relevant to filtration and transparency. This class structure was an engaging way for students to learn principles from ecology, evolution, behavior, and physiology. Challenges with this course design revolved around the interdisciplinary and creative nature of the structure; for instance, the knowledge of the participants was often stretched by engineering details. While the present class was focused on the COVID‐19 crisis, a course structured through a bioinspired approach can be applied to other focal problems, or subject areas, giving instructors a powerful method to deliver interdisciplinary content in an integrated and inquiry‐driven way.