From the WUSTL Newsroom…
Using a high-tech imaging method, a team of biomedical engineers at the School of Engineering & Applied Science at Washington University in St. Louis was able to see early-developing cancer cells deeper in tissue than ever before with the help of a novel protein from a bacterium.
Lihong Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering at the School of Engineering; Junjie Yao, PhD, a postdoctoral researcher in Wang’s lab, and a team of engineers found that by genetically modifying glioblastoma cancer cells to express BphP1 protein, derived from the rhodopsuedomonas palustris bacterium, they could clearly see tens to hundreds of live cancer cells as deep as 1 centimeter in tissue using photoacoustic tomography.
The work, published Nov. 9 in advanced online publication of Nature Methods, is the first to combine deep-penetration, high-resolution photoacoustic tomography with a reversibly switchable, non-fluorescent bacterial phytochrome.
“Genetic encoding of the protein allows us to image and track targeted biological processes deep in tissue,” Wang said. “The optical switching property of the protein enables new imaging capability.”
The BphP1 protein has the ability to sense different types of light and shift its absorption properties accordingly. This feature allows the researchers to take two images of cancerous tissue using the two types of light — in this case, red or near-infrared light — and compare them to get a highly sensitive, high-resolution image of the cancer cells.
Using two embodiments of photoacoustic tomography, both developed in Wang’s lab, that use a combination of light and sound to take an intensely close look at tissues at different length scales, the researchers first illuminated the protein expressed in the cancerous tissue with near-infrared light, causing it to shift its absorption.
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