A readily portable miniature microscope weighing less than 2 grams and tiny enough to balance on your fingertip has been developed. The scope is designed to see fluorescent markers, such as dyes, commonly used by medical and biological researchers studying the brains of mice.

Fig. 1 – Researcher Mark Schnitzer demonstrates the microscope's tiny size and weight.
The new device has no moving parts that would require realignment if the scope gets jostled. Aside from the outer lens, it is sealed against dust, making it well suited for use outside the lab, such as on-the-spot medical screening for diseases like tuberculosis.

The miniature microscope weighs in at 1.9 grams and is three-quarters of an inch tall. The image is displayed on a computer — wherever someone can take a laptop, he or she can also use the microscope. (See Figure 1)

The device was built using readily available technology. Many of the components were originally developed for cell phones and other consumer devices. All the parts could be readily mass-produced, which could make them inexpensive.

Compared to a small, high-resolution fiber-optic microscope developed at the university in 2008, the new device offers a field of view seven times greater and reduces degradation of the image by a factor of five.

It has improved optical sensitivity, higher resolution, and far greater portability than either fiber-optic or conventional desktop-size microscopes.

The researchers have used the microscope to detect tuberculosis in cells cultured in the lab. They also have used an array of four of the devices in experiments to count individual cells cultured in the laboratory, and achieved accuracy comparable to that obtained with standard full-size cell counting equipment.

They have also demonstrated that the microscopes may also be useful for screening for some genetic mutations. The researchers were able to distinguish mutant zebrafish from those lacking the mutation by comparing images of certain nerves.

The current limit to its image resolution is 2.5 microns, or 2.5 millionths of a meter, but just by using state-of-the-art cell phone imagers, that could be improved to 1 micron, researchers say.

This technology was done by Stanford University, Stanford, CA. For more information, visit http://www.stanford.edu .