Glucose is consumed as an energy source by almost all life forms, from bacteria to human. The uptake of glucose by cells closely reflects their energetic needs, and is becoming poorly regulated in many pathological conditions such as obesity, diabetes and cancer.
To image glucose uptake activity at the cellular level, glucose analogues labeled with fluorescent dyes have been developed. Unfortunately, tagging fluorophores onto glucose alters its chemical property. Moreover, fluorescent dyes are always larger than the glucose itself. Therefore, most fluorescent glucose analogues have undesired interactions in cells and tissues, which would bias the true glucose distribution.
To overcome these problems, a research team developed a new modality to visualize glucose uptake activity inside single cells based on stimulated Raman scattering (SRS) imaging, and demonstrated its use in live cancer cells, tumor xenograft tissues, primary neurons and mouse brain tissues.
This technique is able to distinguish cancer cell lines with differing metabolic activities and reveals heterogeneous uptake patterns in neurons, mouse brain tissues and tumor tissues with clear cell-to-cell variations. The border between tumor proliferating region and the necrotic region can be clearly visualized down to single cell with sharp contrast in glucose uptake activity.