Simple chip powered by quantum dots allows standard microscopes to visualise difficult-to-image biological organisms.
Do a Google search for dark-field images, and you’ll discover a beautifully detailed world of microscopic organisms set in bright contrast to their midnight-black backdrops. Dark-field microscopy can reveal intricate details of translucent cells and aquatic organisms, as well as faceted diamonds and other precious stones that would otherwise appear very faint or even invisible under a typical bright-field microscope.
Scientists generate dark-field images by fitting standard microscopes with often costly components to illuminate the sample stage with a hollow, highly angled cone of light. When a translucent sample is placed under a dark-field microscope, the cone of light scatters off the sample’s features to create an image of the sample on the microscope’s camera, in bright contrast to the dark background.
Now, engineers at MIT have developed a small, mirrored chip that helps to produce dark-field images, without dedicated expensive components. The chip is slightly larger than a postage stamp and as thin as a credit card. When placed on a microscope’s stage, the chip emits a hollow cone of light that can be used to generate detailed dark-field images of algae, bacteria, and similarly translucent tiny objects.
Source: “Mirrored chip could enable handheld dark-field microscopes”, Jennifer Chu, MIT News Office