Diagnostics and therapeutics strategies in ALA-PDT by multiphoton excitation using a NIR ultrafast pulse laser source

Gastric cancer is a major cause of cancer-related mortality and is a highly malignant disease with a high morbidity rate. Most deaths from gastric cancer are due to recurrence. We propose a new diagnostic and therapeutic method using multiphoton excitation to expand the application of PDD/PDT. To test the effect of 5-ALA as a photosensitizer on multiphoton excitation PDD/PDT in vitro/in vivo. We used the human gastric cancer cell lines MKN74 and to maintain uniformity in the study population, we used six-week-old female BALB/c mice. We proceeded with the experiment by using 820nm and 1150nm for the multiphoton excitation wavelengths of PpIX. For the evaluation of PpIX fluorescence in cells, there was a clear difference between the presence and absence of 5-ALA for both 820nm and 1150nm light irradiation. In vivo, there were also differences between wavelengths, especially in the results of time-lapse 3D imaging. We evaluated the selection of multiphoton excitation wavelengths specific to 5-ALA and its cytotoxicity. The results could potentially lead to new diagnostics and therapies in the field of PDD/PDT.