Nanotechnology:An Introduction

When K.Eric Drexler popularized the word 'nanotechnology' in the 1980's, he was talking about building machines on the scale of molecules, a few nanometers wide—motors, robot arms, and even whole computers, far smaller than a cell. Drexler spent the next ten years describing and analyzing these incredible devices, and responding to accusations of science fiction.

Much of the work being done today that carries the name 'nanotechnology' is not nanotechnology in the original meaning of the word. Nanotechnology, in its traditional sense, means building things from the bottom up, with atomic precision.

Nanotechnology is the science of using or producing particles that are nanometers in size (nano = 1 billionth) for industrial applications in the medical, chemical, materials, electronics, sensing and other fields.

Nanoparticles by definition, typically have at least one dimension smaller than 100 nm.

Many different types of nanoparticles currently being studied for applications in nanomedicine. They can be carbon-based skeletal-type structures, such as the fullerenes, or micelle-like, lipid-based liposomes, which are already in use for numerous applications in drug delivery and the cosmetic industry. Colloids, typically liposome nanoparticles, selected for their solubility and suspension properties are used in cosmetics, creams, protective coatings and stain-resistant clothing. Other examples of carbon-based nanoparticles are chitosan and alginate-based nanoparticles described in the literature for oral delivery of proteins, and various polymers under study for insulin delivery.

Nanoparticles are man-made, extremely small particles (nanometers or so in size) manufactured for use in a broad spectrum of industries. To put it in perspective, a DNA molecule is 2 nm wide and red blood cells are thousands of nm in diameter. On a nanoscale, particles of even commonly used substances such as copper, change their properties due to their tiny size and large surface area to volume ratios.

In biotechnology, nanoparticles have found extensive use in the cosmetics industry and medicine. In biomedicine, they are used as tools such as imaging agents and drug carriers.

In a press release on April 17, 2007, the American Association for Cancer Research (AACR) reported research presented at the 2007 annual meeting that suggests nanoparticles could cause cancer and should be thoroughly investigated and used with caution.

Because of their ultra-small size, nanoparticles can penetrate cell membranes and integrate themselves into larger molecules. They can resist cellular defense systems but are large enough to interfere with cell processes. Despite widespread use in public consumables such as makeup and creams, and the knowledge that very traits that make them useful might also render them toxic, thorough testing on the safety of nanoparticles, once absorbed through the skin, has not been done. When used for remediation, their release in the environment is also risky due to possible exposure to humans and other animal species.

Despite the unknowns, the general consensus seems to be that there is a lot of potential in nanotechnology and applications using nanoparticles. However, the bioethics of nanoparticle use in medicine are still in question, and much more research is needed before we can determine how they will react in the human body, and interact with biomolecules, and how to ensure their safe use.