https://phys.org/news/2018-06-method-orthotopic-brain-tumor-imaging-clearer.html

Fluorescence imaging in the second NIR window (NIR-II), compared with the first NIR window (NIR-I), exhibits salient advantages of deeper penetration and higher spatiotemporal resolution, owing to further reduced photon scattering, absorption, and tissue autofluorescence in biological tissues. Scientists have designed a new donor-acceptor (D-A)-tailored NIR-II emissive AIE molecule, and formulated dots showed a high NIR-II fluorescence quantum yield up to 6.2 percent, owing to the intrinsic aggregation-induced emission nature of the designed molecule.

The AIE dots have been successfully used for dual NIR-II fluorescence and NIR-I photoacoustic imaging for precise noninvasive brain-tumor diagnosis. Based on the same dots, the experiments revealed that NIR-II fluorescence imaging showed a high resolution.