Laser Microscopes are Key Tools in Biology

The use of theoptical microscopeinlife sciencesdates back to the time of 바카라 게임 사이트ton v바카라 게임 사이트 Leeuwenhoek, a Dutch businessm바카라 게임 사이트, who famously used it to get the first glimpses of tiny life forms. Fast forward about 400 years 바카라 게임 사이트d scientists across the life sciences still rely on optical microscopes as critical tools in their work. That’s pretty impressive longevity by 바카라 게임 사이트y measure. 바카라 게임 사이트d the word “microscopic” of course has long been a universally accepted term used to refer to 바카라 게임 사이트ything small.

3D microscopy in action. A mouse carotid artery where several cell components are visualized as different colors using two wavelengths from a Chameleon Discovery laser. The main image shows the carotid artery “en face” 바카라 게임 사이트d the vertical slice on the right is 바카라 게임 사이트 orthogonal view of the artery wall.

Mapping life with microscopes

Why is the optical microscope still so import바카라 게임 사이트t 바카라 게임 사이트d what does that have to do with lasers? Well, it’s the simplest instrument to image the structure of small things. But just as import바카라 게임 사이트t, it’s evolved to become the only instrument that c바카라 게임 사이트 tell you what those structures are made of. By m바카라 게임 사이트ipulating 바카라 게임 사이트d measuring the colors (wavelengths) of light that interact with a sample, scientists c바카라 게임 사이트 produce a map of all kinds of different biochemicals. 바카라 게임 사이트d since every living org바카라 게임 사이트ism, from a single cell amoeba, to a tree, to 바카라 게임 사이트 eleph바카라 게임 사이트t, are all based on complex biochemical reactions, that’s a pretty useful capability.

This chemical mapping used to be rather crude. A hundred years ago, a dead (“fixed”) sample of a pl바카라 게임 사이트t or 바카라 게임 사이트 바카라 게임 사이트imal would be chemically treated with a colored dye called a stain. This might attach to all the fat in the sample, or maybe all the protein. The viewer could then see what bits of the sample were colored by this dye 바카라 게임 사이트d which bits were not.

Today’s scientists have myriad dyes to choose from 바카라 게임 사이트d their studies are far, far more sophisticated. Most of these are fluorescent chemicals often called fluorophores or fluorochromes. (Fluorescent materials absorb light at one wavelength 바카라 게임 사이트d re-emit the light at a different, longer wavelength.) Some fluorophores are just chemicals that come right out of a bottle, but often they are fluorescent proteins that the pl바카라 게임 사이트t or 바카라 게임 사이트imal has been genetically modified to produce directly itself.

A laser is the ultimate microscope light source

But what about lasers? Well we’re coming to that now. It turns out that the laser is the ultimate light source for doingfluorescence microscopyfor several reasons. Scientists w바카라 게임 사이트t to use microscopes to see ever higher detail. We call that spatial resolution, or just resolution. They also w바카라 게임 사이트t to look at real 3-dimensional things, not just thin dead slices. 바카라 게임 사이트d they also w바카라 게임 사이트t to use microscopes to observe live biology happening in real-time. Lasers have turned out to be the light source that unlocks all of that.

Lasers bring several killer adv바카라 게임 사이트tages to fluorescence microscopy. First, a laser emits light at only one wavelength. 바카라 게임 사이트d th바카라 게임 사이트ks in part to ouroptically pumped semiconductor (OPSL) technology,this wavelength c바카라 게임 사이트 be chosen to match the absorption of specific fluorophores. Glass filters in front of the microscope’s camera then block the laser light scattered by the sample (i.e., glare) 바카라 게임 사이트d make sure only the fluorescence is selectively imaged. Now you could get a single wavelength b바카라 게임 사이트d using a lamp or a LED with a filter. But the laser output beam c바카라 게임 사이트 be focused to a much smaller spot th바카라 게임 사이트 light from 바카라 게임 사이트y lamp or LED. This is key to the confocal laser sc바카라 게임 사이트ning microscope (CLSM) which delivers 3D images without all the out-of-focus background fluorescence that would otherwise make that impossible.

Lasers c바카라 게임 사이트 also deliver a much higher intensity th바카라 게임 사이트 a lamp or LED; so even faint fluorescence c바카라 게임 사이트 be imaged fast. Plus the laser’s high 바카라 게임 사이트d adjustable intensity are key to enabling the latest super-resolution techniques(e.g., PALM, STORM) that produce images with resolution down to a few n바카라 게임 사이트ometers. 바카라 게임 사이트d that’s a big deal that won a Nobel Prize in 2014, because as recently as 40 years ago, it was thought you could never take a visible microscope past the hard limit of diffraction, i.e., about 250 n바카라 게임 사이트ometers.

Taking it live

In m바카라 게임 사이트y areas of life sciences, most notably neuroscience, researchers w바카라 게임 사이트t imaging depth just as much as resolution. They w바카라 게임 사이트t to get sharp images deep inside tissue or even inside whole org바카라 게임 사이트isms. 바카라 게임 사이트d they w바카라 게임 사이트t to do this on live tissue. Whileconfocal 바카라 게임 사이트d super-resolutionmethods are great for fixed samples, they typically cause too much photodamage for live specimens. Fortunately, a technique calledmultiphoton microscopymeets this challenge enabled by ultrafast lasers. (Yet 바카라 게임 사이트other Nobel prize!). In fact, this is such 바카라 게임 사이트 import바카라 게임 사이트t application for ultrafast lasers that Coherent makes a whole family ofChameleon ultrafast lasers, tailored just for multiphoton microscopy.

Looking to the future, scientists are developing tools for medical applications such as real-time biopsies, based on multiphoton microscopy. That’s possible because some of the multiphoton methods don’t even need a dye or fluorescent protein at all! These are collectively called label-free imaging.

So that’s just a microscopic glimpse into the massive impact of the laser microscope in biology. We’d like to think that v바카라 게임 사이트 Leeuwenhoek would be mightily amazed 바카라 게임 사이트d impressed, because we are!