Nanotechnology can be viewed as the science and engineering included in the design, synthesis, characterization, and application of materials and devices whose smallest functional organization is on the nanometer level or one billionth of a meter. At these scales, consideration of individual molecules and interacting groups of molecules becomes important. Applications to medicine imply materials and devices designed to interact with the body at molecular scales with a high degree of specificity.
Nanotechnology and nanoengineering appear to produce important scientific and technological advances in diverse fields including medicine and healthcare. Materials and devices engineered at the nanometer scale imply controlled manipulation of individual constituent molecules and atoms in how they are arranged to form the bulk macroscopic substrate. This, in turn, means that nanoengineered substrates can be designed to exhibit very specific and controlled bulk chemical and physical properties as a result of the control over their molecular synthesis and assembly. For applications to medicine and healthcare, these materials and devices can be designed to interact with cells and tissues at a molecular level with a high degree of functional specificity, thus allowing a degree of integration between technology and biological systems. Nanotechnology is not in itself a single emerging scientific discipline but rather a meeting of traditional sciences such as chemistry, physics, materials science, and biology to bring together the required collective expertise needed to develop these novel technologies.
What is a Nanomaterial?
Nanoscience will impact the design and fabrication of new materials with innovative properties and functions. Contributions to this field include improving the properties of plastics, ceramics, coatings, composites, fibres and many more. Nanoscience also introduces an entirely new concept in material design. As a matter of fact, nature is a great source of inspiration to materials engineers.
The question: What is a‘nanostructured material’? must be considered. Nanostructured materials are solids or semi-solids characterized by a nano-sized inner structure. They differ from crystalline, microstructured and amorphous solids because of the scale order. In contrast, microstructured materials show structural variation only on a micron scale, whereas amorphous materials exhibit short-range order only. In nanostructured materials, the spatial order is at the nanoscale, which lies between the microscopic and the atomic scale.
Nanostructured materials differ from conventional polycrystalline materials in the size of the structural units of which they are composed. They can exhibit properties that are drastically different from those of conventional materials. This means that in a nanostructured material there is a large proportion of surface atoms. Due to the large surface area, bulk properties become governed by surface properties. Examples of nanostructured materials are nanoporous, nanocrystalline, nanocomposite and hybrid materials.
Methods in Nanotechnology
Different methods for the synthesis of nanoengineered materials and devices can accommodate precursors from solid, liquid, or gas phases. In general, most synthetic methods can be classified into two main approaches: “top down” and “bottom up” approaches and combinations thereof.
“Top down” techniques begin with a macroscopic material or group of materials. The best known example of a “top down” approach is the photolithography technique used by the semiconductor industry to create integrated circuits. A similar approach has been used to develop microscale connected wells in agar. Other types of nanolithographic techniques are able to produce true nanoscale features in various materials.
“Bottom up” approaches, on the other hand, begin by designing and synthesizing custom-made molecules that have the ability to self-assemble or self-organize into higher order mesoscale and macroscale structures. The challenge is to synthesize molecules that spontaneously self-assemble upon the controlled change of a specific chemical or physical trigger. Good examples of this are biomineralization-type applications.
Other techniques attempt to mimic the ultrastructure of material without the requirement of deposition on pre-existing metal structures. As these technologies develop, it is expected that these advanced materials will not only provide desirable mechanical properties but also incorporate functional cell signaling properties.
Applications in Medicine and Healthcare
The application of nanotechnologies to the medical sector is known as nanomedicine. This area of application uses nanometre scale materials and nano-enabled techniques to diagnose, monitor, treat and prevent diseases. These include cardiovascular diseases, cancer, musculoskeletal and inflammatory conditions, neurodegenerative and psychiatric diseases, diabetes and infectious diseases and more. The potential contribution of nanotechnologies in the medical sector includes new diagnostic tools; imaging agents and methods; drug delivery systems and pharmaceuticals; therapies; implants and tissue engineered constructions.
But, why nanotechnologies? Nanomaterials, in nanomedicine, often go beyond 100 nm and up to about 500 nm. This is the size range of biomolecules. These natural nanomaterials are the constituents of larger hierarchical structures that regulate the function of the cell. Bacteria and viruses are larger. Basically, nanotechnologies make it possible to create engineering materials that have dimensions on the scale of biomolecules. Nanotechnologies have the potential to improve the whole care process that starts for a patient once a disease is suspected, from diagnosis to therapy. The aim is the development of new materials and methods to detect and treat diseases in a targeted, precise, effective and lasting way.
Recent advances in medical engineering include systems and devices that have a significant potential for improving the treatment of many disorders. However, despite this potential, these approaches all depend on bulk molecular engineering or chemical manipulation of macromolecular structures. Nanoengineered materials and devices designed to interact with cells and tissues or carry out biologically specific functions should offer a much greater degree of integration between technology and physiological systems. At present, applied nanotechnology to medicine and healthcare is at the basic science stage. In other words, the time of nanotechnology is just coming.
 Abbot A, Cyranoski D. Biology’s new dimension. Nature 2003
 Adleman LM. Molecular computation of solutions of combinatorial problems. Science 1994
 Ameer GA, Mahmood TA, Langer R. A biodegradable composite scaffold for cell transplantation. J Orthop Res 2002
 Amiel GE, Yoo JJ, Kim BS, Atala A. Tissue engineered stents created from chondrocytes. J Urol 2001
 Birge, RR. Protein based computers. Scientific American, 1995
 Hanes J, Cleland JL, Langer R. New advances in microsphere-based single dose vaccines. Adv Drug Del Rev 1997
 Held R, Heinzel T, Studerus AP, Ensslin K, Holland M. Semiconductor quantum point contact fabricated by lithography with an atomic force microscope. Applied Phys Letters 1997