A research team has introduced a Raman microscopy method that generates images that are up to eight times more luminous than those produced by traditional Raman techniques. By imaging frozen biological samples, they successfully minimized the interference from material movement during lengthy acquisition times. This innovation is anticipated to enhance knowledge across various biological disciplines by enabling the capture of high-quality images and chemical data without the necessity for staining.
Gaining insights into the behavior of the molecules and cells that form our bodies is essential for progressing in medicine. This necessity has sparked a relentless quest for clearer images of events that go beyond human eyesight. A recent study published in Science Advances by researchers from Osaka University unveiled a method that yields high-resolution images using Raman microscopy.
Raman microscopy serves as a valuable tool for imaging biological specimens since it can offer chemical insights regarding specific molecules—like proteins—that are integral to bodily functions. However, the Raman signals generated by biological samples are often faint, making it easy for background noise to obscure them and resulting in subpar images.
The researchers have engineered a microscope that preserves the temperature of previously frozen samples during imaging. This advancement has enabled them to produce images that can be as much as eight times brighter than those previously obtained through Raman microscopy.
“One primary factor contributing to unclear images is the movement of the entities being observed,” notes Kenta Mizushima, the study’s lead author. “By imaging samples that were frozen and immobile, we could extend exposure times without harming the specimens. This resulted in a higher signal-to-background ratio, enhanced resolution, and larger viewing areas.” The approach does not utilize any stains or chemicals to stabilize the cells, allowing for a true representation of cellular processes and behaviors.
The researchers also validated that the freezing method preserved the physicochemical states of various proteins. This cryofixing technique has a significant advantage over chemical fixation methods, which cannot achieve the same results.
“Raman microscopy provides an additional tool within the imaging repertoire,” says Katsumasa Fujita, the senior author. “It is particularly advantageous as it offers not only cellular images but also data regarding the distribution and specific chemical states of molecules, which is invaluable as we continuously seek to gain the most thorough understanding possible.”
The novel technique can be integrated with other microscopy methods for comprehensive analyses of biological samples and is expected to benefit numerous areas within the biological sciences, including medicine and pharmaceuticals.
