Imaging living cells below the surface has been difficult to accomplish using conventional techniques. Electron microscopy can't be used on living tissue, and optical (light) microscopy can't penetrate very deeply into tissue because light scatters as it travels through tissue near the surface. Yet researchers would like to know more about certain deep-tissue areas of the brain, which are critical to understanding Alzheimer's and Parkinson's disease, for example.
By creating a handheld device based on some of the latest advances in micromotors, lensing and fiber optics, the researchers were able to establish a new technique that enables them to obtain microscopic images deeper in the living brain than was possible before microendoscopy. "We're bringing two-photon imaging to endoscopy and we're putting it all into a miniaturised package," says Mark Schnitzer, the team leader on the Optics Letters paper.
The Stanford researchers have used their two-photon microendoscopy technique to glean the detailed images of the blood vessels in the hippocampus sections of the brains of live mice. The mice were injected with a fluorescein dye – an FDA-approved contrast agent that is most commonly used for retinal exams in humans. The fluorescein labeled the blood plasma so the vessels in the brain could be clearly seen.
There are many different options for further exploration, now that the technique has been successfully demonstrated, ranging from biomedical research to clinical imaging applications. The Stanford researchers will be looking into several of those options.
"This is a portable handheld device with the power of two-photon imaging - the full functionality of a microscope that fits in the palm of your hand," says Schnitzer, indicating that this is what makes the technology eminently marketable.
MEDICA.de; Source: American Institute of Physics