Materials Research to Meet 21st-Century Defense Needs (2003) / Chapter Skim
Currently Skimming:
7 Bioinspired and Bioderived Materials
7 Bioinspired and Bioderived Materials
Pages 181-210
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 181... ...
The potential impact of applying biological paradigms to the development of materials to meet DoD requirements was reviewed in depth. Biological systems have clearly shown that large numbers of molecules, structures, and systems in living organisms possess attractive materials properties that are beyond the reach of current nonbiological synthetic approaches.
|
From page 182... ...
Where biological molecules or cells are the active component of a device, the challenge to the materials community is not only incorporation of the sensing entity but, also, and perhaps more important, the preservation of biological function in a nonbiological environment. The common theme for all these technologies, research areas, and applications is to use biological paradigms for the solution of problems of materials design, materials synthesis, and systems assembly.
|
From page 183... ...
How applying biological paradigms will affect the development of materials meeting DoD needs, and ~ .
|
From page 184... ...
Many of the examples cited below represent either the reality or the prom ise of th is i ntegration. DOD NEEDS FOR BIOINSPIRED AND BIODERIVED MATERIALS Mankind has been using biological materials for defense purposes for millennia: wooden staffs for spears or ax handles, vines for ropes, snake venom or plant extracts for biological weapons, shaped bone for tools and weapons.
|
From page 185... ...
The challenge lies in identifying relevant defense applications and understanding and manipulating the biological systems to solve them. It must be borne in mind, however, that the actual use of biological materials or materials that mimic biological systems lags far behind our enthusiasm for them.
|
From page 186... ...
"Computers in the future may weigh no more than 1.5 tons." Popular Mechanics, 1 949 What, then, do living organisms do that might be exploited for defense applications? What do we know now about these molecules or processes and what do we need to understand to bridge the gap to application?
|
From page 187... ...
Biology limits itself by not making use of the vast majority of naturally occurring elements. Biological structures and systems are extremely complex, far more so than their synthetic analogues, and are therefore extremely difficult to manipulate consider bone compared to titanium or even sophisticated alloys.
|
From page 188... ...
On the other hand, the biological synthesis of functional or structural materials using recombinant DNA technology has not progressed as rapidly as materials for human therapy. One of the main reasons is the lower value added for bioderived materials not targeted to the health care market.
|
From page 189... ...
When laminated hierarchical structures of biological systems (e.g., the nacre of abalone shell) are mimicked in microlaminated ceramic-metal, ceramic-organic, or organic-organic composites, significant improvements in composite mechanical properties are observed (Figure 7-21.
|
From page 190... ...
However, although these accomplishments attest to the value of transferring lessons from biology and mimicking biological structures to create synthetic analogs, the smallest length scale in a complete system is still in the micron range due to the intrinsic limitation of the tape-casting method employed. On the other hand, the biosynthesis of inorganic biomaterials has not received the same magnitude of research funding as the human health care area.
|
From page 191... ...
For example, David Tirrell of the Department of Chemical Engineering at California Institute of Technology has proposed to replace the natural amino acids in native protein polymers using both chemistry and biotechnology to generate such materials with unique added functionalities. New types of polymers with well-defined selectable sequences and uniform composition are possible using these biological production methods.
|
From page 192... ...
Molecular or polymeric devices are also more likely to provide a stable interface between electronic equipment and the human nervous system for performance enhancement, prosthetics, and health monitoring. Biology offers insight into how self-assembled molecular-level electronic devices may be printed onto flexible substrates at low processing temperatures.
|
From page 193... ...
Bioinspired and Bioderived Materials Ag-on-Au, stencil mask SAM of HS (CH2~15CO2H _~ _ ~ ~ i _ _ ~ ~ ~ FIGURE 7-3 Calcite crystals grown on self-assembled monolayers on a patterned surface: (a) at short times, the deposition follows the outline of the pattern; (b)
|
From page 194... ...
Biology thus offers 2Berger, T., "Memory Implants for Human Performance," paper presented to the Panel on Bioderived and Bioinspired Materials of the Committee on Materials Research for Defense After Next, National Research Council, Irvine, CA, October 10, 2001. 3Bertozzi, C., "Engineering Cell/Material Interfaces," paper presented to the Panel on Bioderived and Bioinspired Materials of the Committee on Materials Research for Defense After Next, National Research Council, Irvine, CA, October 10, 2001.
|
From page 195... ...
In mammals, the Golgi tendon organs are located at the junction between the muscle and the tendon that connects it to bone. While the muscle spindles are sensitive to passive stretching of the muscle, the Golgi tendon organs are in series with the muscle and so sense the load on the muscle.
|
From page 196... ...
Specific biological sensing presumably operates as a lock-and-key, or more precisely as an induced-fit-through-conformational-change system where a set of intermolecular interactions are defined by the geometry of a receptor site and a complex target molecule. Recent advances in studies of cellsurface interactions have shown that short peptide sequences (such as RGD)
|
From page 197... ...
A second approach is to engineer a cell to produce fluorescent protein in response to a given stimulus. This case relies on activation of a gene, production of nucleic acid, and ribosomal protein synthesis, which will cause the response to be much slower.
|
From page 198... ...
Improved energy densitieswill either require fuel cells or wholly new systems. Fuel Cells Fuel cells represent an attractive alternative to batteries.
|
From page 199... ...
In both batteries and fuel cells, we have long recognized that the distance scale is the key to power density. Diffusion is fast over short distances, while thick electrolytes and electrodes require high ion mobility that compromises our structural choices.
|
From page 200... ...
Previous remarks about the need for flexible barrier materials for organic electronics also apply to batteries and fuel cells. Battery casings impose rigidity and are a significant source of weight.
|
From page 201... ...
These are expected to be all-agent capable and reprogrammable for detecting emerging threats. The fundamental scientific and technological advances required to accomplish these lofty objectives were discussed in Opportunities in Biotechnology for Future Army Applications (NRC, 2001)
|
From page 202... ...
These factors i ncl ude an adequate blood supply to the heal i ng tissue, revel ution of associated infections, infiltration of the wound site by inflammatory cells followed by mesenchymal cells, and finally the deposition of neoconnective tissues and epithelial tissues. An adequate blood supply to injured tissue has long been recognized as vital to healing.
|
From page 203... ...
There is an inevitable gap between in vitro phenomena that occur under carefully controlled conditions, such as ideal concentrations of ir growth factors that have predictable effects on selected cell lines, and practical situations that involve the complex of mammalian systems and a plethora of different growth factors (both stimulatory and inhibitory) in environments complicated by infection, tissue necrosis, and external extremes.
|
From page 204... ...
However, in this section we are considering the role of materials in increasing human performance substantially beyond the optimal native condition of the human body. This panel believes that many operations would have dramaticaliv improved chances for success if nominal body performance is enhanced.
|
From page 205... ...
Bioinspired and Bioderived Materials TABLE 7-2 Current Human Enhancements and the Materials Enhancements They Depend On Human Enhancement Technology Materials Enhancement Contact and intraocular lenses Hearing aids Cochlear prostheses Tooth implants Larynx implants Silicone implants Joint and bone replacements Artificial blood Vascular pumps, implants, and stents Renal dialysis Transparency, fluid biocompatibility Ear mold softness, microcircuits, batteries Electrode compatibility Hardness, durability, anchoring Elasticity Biocompatibility, natural feeling Hardness, durability, bone compatibility Membrane permeability, ductility Vascular lining, flexibility Membrane permeability TABLE 7-3 Human Body Functions That Could Potentially Be Enhanced and the Materials Advances Required Body Function Materials Advances Required Locomotion/muscular activity Nervous system control signals Energy sources for muscles, electronic implants for muscle tone, increased structural integrity for tendons and bone: microfluidics, micromaterial engineering Understanding signal transmission and materials improvements for nerves: tissue engineering Energy management Energy uptake, enhanced long-term delivery to tissue, improved waste removal: molecular coatings, enhanced excretion Oxygen management Improved gas exchange for uptake and excretion, artificial blood: surfactant development, tissue surrogates Physical integrity Skin, eye, and mucous membrane protection: tissue integrity, protection from radiation Thermoregulation Heat retention and rejection, energy recycling: smart materials that recognize the external environment Cognition/mental states Energy and toxin management for the central nervous system: drug delivery systems 205
|
From page 206... ...
The panel selected the following research and research management priorities as critical for realizing the opportunities for bioinspired and bioderived materials research for meeting future defense needs. Improving Fundamental Understanding of the Relationships Between Biological Structure, Properties, and Evolution and Materials Design and Synthesis Recent studies of biological systems have clearly shown that large numbers of molecules, structures, and systems in living organisms possess 206
|
From page 207... ...
· Many molecules, structures, systems, and natural fabrication processes have the potential to serve as the basis for materials with enhanced properties for defense applications, either directly adapted or as a pattern for nonbiological mimics. Increasing Communication of DoD Material Needs to Biological and Physical Scientists Progress at the interface between biological and physical scientists is hampered by educational differences and a general lack of communication, especially the lack of communication of DoD materials needs to the biological community.
|
From page 208... ...
New materials for implantable, multifunctional, and tissue-interactive devices are required: Emphasis should be placed on materials for the microfluidic movement of biologically active molecules to specific tissues and on materials to interface with electrically active tissues. Development of Packaging Technologies to Presence the Biological Function of Biologically Enabled Devices Preservation of the biological function of biological molecules is a key driver for the next generation of biologically enabled devices.
|
From page 209... ...
2002. Spider silk fibers spun from soluble recombinant silk produced in mammalian cells.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.