Nano

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Smallness has been a most unappreciated attribute. We’re always implored to think “big,” and never “small.” But now smallness sits at the convergence of chemistry, physics, and biology at a place called nanotechnology, which is transforming the world of scientific research and development and which is going to have an enormous impact on medicine. Despite its emergence only at the end of the last century, nanotechnology is already a multibillion-dollar phenomenon, with more commercial applications arriving on the scene at an ever increasing pace.

In the nanotechnology arena, small is very small indeed. The basic unit of length is the nanometer: one-billionth of a meter. Consider that if a marble were to represent a nanometer, then the entire earth would represent a meter. A hydrogen atom is approximately a tenth of a nanometer in diameter; a DNA molecule is 2 to 3 nanometers thick. Among living organisms, viruses range from 20 to 400 nanometers; bacteria are larger. Salmonella, the cause of typhoid fever and 90 percent of cases of food poisoning worldwide, is on the order of 2,500 nanometers in length and about 500 nanometers in width, with a narrow tail-like flagellum, also 500 nanometers long. The cells making up the human body are larger, with the disc-shaped red blood cell coming in at a diameter of around 7,000 nanometers, while white blood cells are 10,000 nanometers plus.

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