A Criterion of Colorectal Cancer Diagnosis Using Exosome Fluorescence-Lifetime Imaging

This study was aimed to investigate the applicability of the exosome fluorescence-lifetime imaging microscopy (FLIM) for colorectal cancer (CRC) diagnosis. Differential ultra-centrifugation was used to extract exosomes from the blood plasma of 11 patients with colon polyps (CPs) and 13 patients with CRC at the T2-4, N0-3, and M0-1 stages. Analysis was performed using a two-photon FLIM device. In total, 165 and 195 FLIM images were recorded for the CP and CCR patient groups, respectively. Two classes of exosomes differentiated by autofluorescence average lifetime [Formula: see text] were discovered in the samples. The first class of exosomes with [Formula: see text] = (0.21 ± 0.06) ns was mostly found in samples from CRC patients. The second class with [Formula: see text] = (0.43 ± 0.19) ns was mostly found in samples from CP patients. The relative number of “CRC-associated” exosomes [Formula: see text] in the FLIM dataset was shown to be very small for the CP patient group and large for the CRC patient group. This difference was statistically significant. Therefore, the suggested CRS diagnostics criterion can be as follows. If [Formula: see text] > 0.5, the probability of CRC is high. If [Formula: see text] < 0.3, the probability of CRC is low.