Fig. 2.

FLIM reveals metabolism impact unique to GSC lines through mean lifetimes in fixed xenograft tissues. Metabolic mapping of NADH is sensitive to showing the difference between more focal tumors (a) 12.1 GSC and (b) more-invasive tumors 44 GSC, (c) U87 nonstem cell tumors, and (d) healthy mouse brain. Mean lifetimes decrease from (a) to (d), reflecting the unique impact that stem cell lines have on the tumor microenvironment. All mean NADH lifetimes of GBMs and amount of bound NADH ($a_2\%$) were significantly greater than the normal mouse brain (Student’s $t$-test, $p<0.0001$ for both mean lifetime and $a_2\%$). FLIM data taken using time-domain collection multiphoton microscope and $60\times$ oil immersion objective (Nikon). Scale bars are $50\mu \mathrm{m}$.