Up to the Moment

The Center for Biologically Inspired Design Seminar Series continues throughout 2007-2008
with Vladimir Tsukruk on September 10, 2007
and Daniel Goldman on September 28, 2007.
Future talks will be announced here and in Georgia Tech College bulletins.
Abstracts of these speakers can be found below.

Dr. Vladimir Tsukruk
School of Materials Science and Engineering &
School of Polymer, Textile, and Fiber Engineering,
Georgia Institute of Technology

Testing biological materials and sensory structures: touching spider legs and fish skin

September 10, 2007

Abstract: Investigation of key properties of biological materials relevant to the development of artificial bioinspired micro-flow (air and fluid) sensors is a recent focus of our research group. We utilized surface force spectroscopy for direct point-load measurements of the nanomechanical response of the cuticle and pads on the legs and wind-sensing hairs of spiders. These measurements allowed for calculations of the torsional constant of the spider hairs, the elastic modulus of cuticle and pads, and viscoelastic (frequency-dependent) deformation of pads relevant to spider ability to monitor minute air pressure variations. In other study, superficial sensor cupulae of several fish were compared in terms of size, distribution, morphological differences, and mechanical responses in comparison with the dome-shaped hydrogel structures of artificial hair sensory lateral lines of a dummy fish capable of tracking an oscillating target.
learn more | Science Daily

Dr. Daniel Goldman
School of Physics and Graduate Program for Bioengineering
Georgia Institute of Technology

Control of Substrate Properties to Discover Principles of Locomotion

12:00 PM, Friday, September 28, 2007 Suddath Seminar room, Petit Institute for Biotechnology and Bioscience, IBB building

Abstract: Biological organisms negotiate complex terrain in ways that no human-made robot can. While there has been progress made in the study of terrestrial locomotion on rigid, level, high friction substrates, understanding how organisms move over materials that present a complex foot interaction (like sand, bark, leaves, grass) is still a challenge. This talk will describe two examples of how controlled laboratory experiments can be used to investigate the mechanisms that organisms use to negotiate complex terrestrial environments. Spiders and cockroaches maintain high speed across substrates with low foothold probability, like debris. Laboratory experiments on wire mesh (with 90% of material removed) reveal that they achieve such performance by distributing contact along limbs. Spine and hair structures on the limbs increase effective contact; the addition of prosthetic structures to the limbs of ghost crabs and a bioinspired robot RHex enhances performance on wire mesh. A fluidized bed, a collection of granular media forced by a flow of air, is used to vary the strength of sand to study the performance of rapidly running sand-dwelling lizards and crabs. While crabs suffer a decrease in speed as the material weakens, surprisingly the lizards maintain high speed, even when the material is fully fluidized. Recent results on experiment and simulation of a physical model of an organism (a robot) running on granular media will be discussed.

image: D.Goldman, et al
profile| publications

Dr. Silas Alben

Georgia Institute of Technology, School of Mathematics

Hydrodynamics of Flexible Thrusters (fish fins)

3:00 pm, Monday, October 15, 2007, L1205 Ford ES&T

Abstract: Ray-finned fishes are a group of over 28,000 species, comprising more than half of all vertebrates, that have diversified into a wide variety of aquatic habitats and are known for their diversity of locomotory styles. One of the key characteristics of ray-finned fishes is the presence of fins that extend into the water and act as control surfaces during locomotion. We have studied the mechanical properties of fin rays, which are a fundamental component of fish fin structure. We have derived a linear elasticity model which predicts the shape of fin rays given the input muscle actuation and external loading. The model agrees well with experiments: both show a concentration of curvature at the ray base or at the point of an externally-applied force, and a variation in ray stiffness over more than an order of magnitude depending on actuation at the bases of the fin rays.

profile and learn more | PDF

Dr. David Hu
Adjunct Lecturer, Courant Institute, New York University

Propulsive Mechanisms of Surface Swimming

3:00 pm, Monday Oct 22 L1205 Ford ES&T

Abstract: Two studies in biolocomotion: walking on water and slithering on land. We consider two physical systems, one dominated by the influence of surface tension, the other by friction. We first present an experimental study of the hydrodynamics of water-walking insects and spiders. Particular attention is given to rationalizing their propulsion mechanisms using scaling and flow visualization. In the second part of the talk, we consider the propulsion of snakes over land, which is accomplished using a variety of techniques, including a unidirectional accordion-like mode, lateral sinuous slithering and sidewinding. In a simple computational mass-spring model, we prescribe the muscle activity of the snake and then calculate its motion as required by the torque and force balances on its body. A key feature of our model is that it allows us to rationalize the mode of locomotion of the snake on the basis of propulsive efficiency.

  website | article | PDF

Dr. Kellar Autumn
Associate Professor of Biology, Lewis and Clark College

Geckos: biological inspiration for smart adhesives and climbing robots

3:00 pm, Monday, November 5, 2007, L1205 Ford ES&T

Abstract: The millions of tiny hairlike nanostructures on geckos' toes are helping engineers to develop self-cleaning nontoxic adhesives. It is remarkable that scientific curiosity about how a lizard can climb on the ceiling has lead to valuable advances in nanotechnology. Research on adhesive nanostructures in geckos is an example of how basic science can lead to serendipitous discoveries that have broad applications. We showed that a gecko's toe adheres to surfaces by a nanostructure, not chemical glue. Subsequently, we have discovered that the gecko adhesive is self-cleaning, directional, and mechanically controllable. This has led to the development of synthetic adhesive nanostructures that may be used in medical, sports, and household applications, and may reduce the need for toxic glues and solvents in general assembly. I will review our past and current research on the gecko adhesive, and also discuss some of our recent collaborations with engineers in developing legged climbing robots for space exploration and search and rescue applications. My seminar will conclude with a discussion of future directions in the new field of gecko adhesives.

  bio  |  Autumn Lab  |  article

Dr. Cheryl Hayashi
Associate Professor of Biology, University of California, Riverside

Biomechanics and Molecular Biology of Spider Silk

December 3, 2007

Abstract: Blueprint for a High-Performance Biomaterial: Full-Length Spider Dragline Silk Genes. Spider dragline (major ampullate) silk outperforms virtually all other natural and manmade materials in terms of tensile strength and toughness. For this reason, the mass-production of artificial spider silks through transgenic technologies has been a major goal of biomimetics research. Although all known arthropod silk proteins are extremely large (>200 kiloDaltons), recombinant spider silks have been designed from short and incomplete cDNAs, the only available sequences. Here we describe the first full-length spider silk gene sequences and their flanking regions. These genes encode the MaSp1 and MaSp2 proteins that compose the black widow's high-performance dragline silk. Each gene includes a single enormous exon (>9000 base pairs) that translates into a highly repetitive polypeptide. Patterns of variation among sequence repeats at the amino acid and nucleotide levels indicate that the interaction of selection, intergenic recombination, and intragenic recombination governs the evolution of these highly unusual, modular proteins. Phylogenetic footprinting revealed putative regulatory elements in non-coding flanking sequences. Conservation of both upstream and downstream flanking sequences was especially striking between the two paralogous black widow major ampullate silk genes. Because these genes are co-expressed within the same silk gland, there may have been selection for similarity in regulatory regions. Our new data provide complete templates for synthesis of recombinant silk proteins that significantly improve the degree to which artificial silks mimic natural spider dragline fibers.

  bio | article | PDF

Luke Lee
Director, Biomolecular
Nanotechnology Center

New breakthroughs in
biomimetic compound
eye research

January 14, 2008

Luke Lee, Lloyd Distinguished Professor, Bioengineering, Director, Biomolecular Nanotechnology Center, and Co-Director, Berkeley Sensor & Actuator Center (BSAC) focuses his research on BioPOEMS and BioMEMS for advanced biomolecular chips and clinical applications. His current research projects include: Micro Confocal Imaging Arrays (mCIAs) for single molecule detection and imaging; Integrated Microfluidic Optical System (IMOS) for biochemical processors with microfluidic logics; Integrated Near Field Optical Microfluidic Device (INFOMD) for multiple optical trapping, excitations, and manipulations of biomolecules in microfluidic chips; Neural probes with nanoscale biomimetic structures for biocompatible neural interfaces; Organic MEMS for cell based bioinfomatic chips using a new polymer micromachining and disposable materials. The primary goal of these projects is to develop an effective hybrid integration of micro-laser diodes and optical systems with polymer-based MEMS devices.

Abstract: Artificial Compound Eye Biologically inspired compound eyes have been developed by a novel 3D microfabrication method, which is inspired by the unique optical scheme of the natural compound eyes found in many insects. The combination of polymer microlenses, reconfigurable microtemplating, soft lithography and self-written waveguides by self-aligned 3D photo-polymerization step enables the realization of complicated optical structures with thousands of omni-directional self-aligned microlens and waveguide arrays in a photosensitive polymer resin. The characterizations of artificial ommatidia and compound eyes have been carried out with a modified reflection/transmission confocal microscope. This work offers a promising new paradigm for constructing miniaturized optical systems for omni-directional detection, wide field-of-view or fast motion detection.

  profile  |  New York Times article

Anette Hosoi
Assistant Professor of Mechanical Engineering at the Massachusetts Institute of Technology

New breakthroughs in mucus-aided travel

April 14, 2008

Anette "Peko" Hosoi, Assistant Professor of Mechanical Engineering at the Massachusetts Institute of Technology pursues fluid dynamics, granular materials, free surface flows, surface tension effects, particle laden flows, numerical methods, and fluid flow coupled to elastic boundaries with her research group. "It's like when you want to move a carpet," Hosoi explained about the pressure crawling method. "You can grab one end and pull, but that's hard. To move it a couple feet, you can go to one end and make a bump and then push that bump along the carpet until it has shifted. The waves are analogous to that bump in the carpet."

Abstract: research interests include: biomineralization, biomimetics, multifunctional biomaterials, crystal engineering, nanofabrication, control of crystal nucleation and growth, colloidal assembly. She has discovered a unique function of biologically formed single calcite crystals serving not only as skeletal armor, but also as an array of microlenses with nearly-perfect optical performance. In addition, while at Lucent she has developed a new biomimetic approach for the synthesis of ordered mineral films with highly controlled nucleation density and crystal sizes using organized organic assemblies.

  Peko Lab  |  Robosnail Video

Dr. Phillip Messersmith
Professor of Biomedical Engineering and of
McCormick School of Engineering and Applied Science,
Northwestern University

Adhesive Strategies in Nature: Mussels, Geckos and their Synthetic Polymer Mimics

February 11, 2008

One area of research for Phillip Messersmith, of Northwestern University, is a hybrid biologically inspired adhesive consisting of an array of nanofabricated polymer pillars coated with a thin layer of a synthetic polymer that mimics the wet adhesive proteins found in mussel holdfasts. Wet adhesion of the nanostructured polymer pillar arrays increased nearly 15-fold when coated with mussel-mimetic polymer. The system maintains its adhesive performance for over a thousand contact cycles in both dry and wet environments. This hybrid adhesive, which combines the salient design elements of both gecko and mussel adhesives, should be useful for reversible attachment to a variety of surfaces in any environment.

The chart above depicts the rational design and fabrication of wet/dry hybrid nano-adhesive. Electron-beam lithography was used to create an array of holes in a PMMA thin film supported on Si (PMMA/Si master). PDMS casting onto the master is followed by curing, and lift-off resulted in gecko-foot-mimetic nanopillar arrays. Finally, a mussel-adhesive-protein-mimetic polymer is coated onto the fabricated nanopillars. The topmost organic layer contains catechols, a key component of wet adhesive proteins found in mussel holdfasts. (Credit: Nature)

  lab profile  |  National Geographic News article

Dr. Kristi Morgansen
Department of Aeronautics and Astronautics
University of Washington

Fin Actuated Autonomous Underwater

3:00 pm, Monday, February 25, 2008

Abstract: Inspired by nature, our intent is to generate novel bio-inspired systems that can out-perform existing engineered systems in speed, agility and efficiency. We focus on bioinspired actuators (based on fish-fin type structures) to control fluid dynamic artifacts (both in and away from the boundary layer) that will ultimately affect speed, agility, and stealth of air and underwater autonomous vehicles. Many underwater vehicles use propellers: propellers provide high thrust, high drag, and low maneuverability. Vehicles using a fish-tail type system are more maneuverable, have the potential to turn in much shorter and more constrained spaces, to have lower drag, to be quieter, and to be more efficient. Modeling of the fluid/actuator system must yield results both (a) amenable to control-theoretic studies and algorithm design, and (b) accurately representing reality. A simple prototype of such a system with rigid foils (shown here) has been simplistically modeled by assuming only primary fluid effects (e.g., quasistatic lift and drag, and added mass) and ignoring all secondary effects (e.g., wall and surface effects). While this approach may seem prohibitively simplistic, the resulting model is in fact capable of representing the qualitative physical performance in simple steady regimes. Our current work focuses on refining the model and extending it to more aggressive operation such as for flexible foils.

image: K.Morgansen, et al
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biomimicry defined

Mid-Course Correction: Toward a Sustainable Enterprise:
The Interface Model

by Ray C. Anderson

Mid-Course Correction

Mid-Course is the personal story of Ray Anderson's realization that businesses need to embrace principles of sustainability

human plus nature

Ecological design transforms awareness by making nature visible. It awakens our sense of belonging to a wider natural world. Ultimately, it brings us home.

Sim Van Der Ryn & Stuart Cowan
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CBID is an interdisciplinary center for research and development of design solutions that occur in biological processes. Founded in 2005, It is one of more than 100 interdisciplinary research units funded at Georgia Institute of Technology