Biological smart materials

There is a great need for strong materials such as alloys that can snap back into shape. Medical applications include prostheses— artificial limbs—and implanted devices such as heart valves. Most biological substances are smart, and the ability to replace lost or injured tissues and organs with smart materials would be a tremendous medical advance. 

Newnham R.E., Amin A., Smart materials acting as both sensors and actuators can mimic biological behavior Chem. Tech., 29 (12) (1999) 38-46. 

Smart materials such as these illustrate an important technological direction for materials science the design of materials with sophisticated properties that behave more like biological systems. Let s briefly recap our history. In Chapter 4 we noted a significant period of discovery when people modified natural polymers to improve their properties. We can call this period, roughly before 1900, Stage 1, and it asked the question, How can I improve upon nature This was followed by a century of synthetic polymer science in which... 

In the recent past, there have been a number of reports on self-assemblies of molecules as advanced materials or smart materials . Without question, the inspiration for this exciting work comes from the biological world, where, e.g., the lipid bilayer of cell membranes plays a pivotal role. In this cormection it should be stated that many other researchers have also described self-assembling systems such as the liposome. Liposomes are modeled after biomembranes, which have been extensively investigated since the late 1960s (see Table 1 for references). 

Supramolecular stabilization provides an excellent opportunity to store highly reactive species or to obtain species not available by traditional methods in high concentration. The phenomenon plays an important role in stabilizing drugs and may be useful in the creation of new methods of separation and purification, the design of new functional and smart materials, and the development of new approaches to chemical and biological research. 

On the other hand, alginate structure can also be chemically modified in order to design smart materials for special applications. The reactivity of alginate functional groups can be exploited as a potential tool for the modification of interesting properties such as solubility, hydrophobicity, and physicochemical and biological characteristics. 

Smart materials are modelled upon biological systems with sensors acting as a nervous system, actuators acting as muscles and microprocessor controllers acting as a brain. These concepts are currently being applied to advanced composite materials where sensors and actuators can be embedded during fabrication (Davidson 2002). 

A definition broad enough for the nanosciences would be to consider them as the body of research focused on the synthesis and the study of nanoobjects, enhanced by their properties (physical, chemical or biological) as well as the discovery of assembly methods allowing access to nanomaterials and also of organizational methods which make it possible to attain smart materials. 

Pluronics have been previously used as a smart material for a range of biology-inspired engineering applications including protein delivery, DNA sequencing, and controlled drug delivery (85). 

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