Fluorescence: What and Why
When asked what PTI "does," the answer is both simple and difficult. We are a manufacturer of research instruments. What kind? In a word, fluorescence. That word, however, opens a Pandora's Box. Scientists could go on for hours about the mechanics of an otherwise simple phenomenon, splitting hairs over technicalities, and otherwise thoroughly confusing the uninitiated.
To most lay people, the word is generally familiar. Fluorescent lamps. Fluorescent paints. But PTI does not make lamps or paints. Rather, we make sophisticated instruments that utilize principles similar to those that make fluorescent lamps and paints glow.
To understand fluorescence, one need not know much more than how we see. Light falls on the objects around us. These objects reflect back some of the light. Our eyes detect this light, and our minds form an image. Fluorescence is nothing more than a variation on the very same simple theme. When light falls on objects, the light that is reflected is almost always modified. White light strikes a blue ball. The ball absorbs all colors but blue, which it reflects to our eyes. And our eyes are equipped to distinguish colors--which helps us identify the object.
Quite frequently, objects are reflecting more than meets the eye. The blue ball, for instance, may also be reflecting some forms of light we cannot see--infra-red or ultraviolet, both of which are invisible to us, but which can be detected with special instruments.
Why would we want to detect this light? Because it can tell us things about the object that we cannot otherwise know. Things such as the object's precise chemical composition. Or the presence of foreign substances on or in the object. Which brings us to the "why" of our business.
Fluorescence is a very tantalizing form of vision. Fluorescence has allowed man to make some of the greatest strides toward understanding Alzheimer's, cancer and many other serious diseases.
Fluorescence can be used to detect viruses such as AIDS or eboli, or probe soil for toxins such as petrochemicals. Fluorescence can be used to monitor the activity of drugs on the human nervous system. Fluorescence can be used to identify DNA and other biological samples.
Other technologies can make the same claims, but the fluorescence technique has several key advantages:
- Fluorescence is harmless to the sample. Living cells can be studied with no adverse effects. For instance, we can watch a heart muscle cell contract as it is stimulated by calcium ions, in real time.
- Fluorescence produces no toxic waste. Some competing research techniques utilize radioactive and biohazardous materials, which must somehow be disposed of after the research is completed.
- Fluorescence is economical. The hardware is relatively simple, comparatively inexpensive, and very versatile--the same instrument can be used to perform multiple techniques.
It is for these reasons and more that PTI has made fluorescence research its business. Fluorescence is our vision—in more ways than one.