Fig. 7.

Positive linear correlation between characteristic Raman peaks and levels of PD-L1 expression. A, qPCR, B, Western blot, C, immunofluorescence images, D, Flow cytometry and E, Average Raman spectra of GL261 cells with different levels of PD-L1 expression. The grey regions in E indicate the characteristic Raman peaks of PD-L1. F and G, Linear regression analysis between the levels of PD-L1 expression and the Raman peak intensities at 836 and 874 cm⁻¹, respectively. Scale bar: 20 μm.