Photodynamic therapy (PDT) is a two-stage treatment that implies the use of light energy, oxygen, and light-activated compounds (photosensitizers) to elicit cancerous and precancerous cell death after light activation (phototoxicity). The biophysical, bioengineering aspects and its combinations with other strategies are highlighted in this review, both conceptually and as they are currently applied clinically. We further explore the recent advancements of PDT with the use of nanotechnology, including quantum dots as innovative photosensitizers or energy donors as well as the combination of PDT with radiotherapy and immunotherapy as future promising cancer treatments. Finally, we emphasize the potential significance of organoids as physiologically relevant models for PDT.

Present-day pterygote insects have two pairs of wings, one in the mesothorax (T2), the other in the metathorax (T3), and both have diverged in structure and function in different groups. Studies in endopterygote and paraneopteran species have shown that the gene Ultrabithorax ( Ubx ) specifies the identity and wing structure in T3, whereas the gene apterous ( ap ) significantly contributes to forming modified T2 wings. We wondered whether these Ubx and ap mechanisms operate in the lineage of polyneopterans. To explore this possibility, we used the cockroach Blattella germanica (Polyneoptera and Blattodea), in which the T2 wings are sclerotized (tegmina), whereas those of the T3 are membranous. We found that Ubx determines the structure of T3 and the membranous wing, while ap significantly contributes to form the sclerotized T2 tegmina. These results along with the studies carried out on the beetle Tribolium castaneum by Tomoyasu and collaborators suggest that ap plays an important role in the sclerotization and melanization of the T2 wings in neopteran groups that have sclerotized forewings. In turn, the sclerotizing properties of ap demonstrated in beetles and cockroaches suggest that the origin of this function goes back to the emergence of Neoptera, in the mid Devonian.