Florescence, microscopic imaging may expand view of cellular processes inside tumors

European researchers have developed a robust macroscale imaging technique based on florescence lifetime imaging microscopy (FLIM) that can analyze cellular processes up to four centimeters in size. With future development, the technique has the potential to identify edges of tumors during surgery. 

A study published in the July issue of Optics Letters demonstrated the use of this first of its kind confocal microscopy macro-FLIM system. 

“Our macro- FLIM system can not only obtain a sample’s structural information, but also allows observation of certain biochemical processes taking place within the sample,” said lead author Vladislav Shcheslavskiy, PhD, a senior research scientist at Becker & Hickl in Berlin, in a prepared statement. “Although our goal is to develop this for clinical use, it could also be very useful in fundamental studies for probing biological processes as disease develops or investigating biological responses to different types of therapy.”

The macro-FLIM system incorporates lasers with short pulses and electronics that count photons and plot their distribution, according to the researchers. 

Shcheslavskiy and colleagues, including those from Privolzhskiy Research Medical University in Russia, used the imaging system to observe the metabolic process of an entire malignant tumor inside a live mouse. The system was able to image fluorescent microbeads and live cancer cells distinguished with florescent dye to analyze the tumor, the researchers wrote. 

The researchers measured the fluorescence lifetime of a genetically encoded red fluorescent protein, which indicated the location of the tumor, as well as a molecule responsible for the energy production in living cells, nicotinamid adenine dinucleotide (NADH).

“The sensitivity of our system was high enough to observe fluorescence of intrinsic tissue components such as NADH without any labeling,” Shcheslavskiy said. “In addition to being used to study metabolism in a tumor, macro-FLIM could be used to follow cell death or oxygen status of tumors on a macroscale with cellular resolution.”