Acknowledgements: This manuscript is dedicated to Dr Raoul Kopelman (October 21, 1933–July 20, 2023). RK acknowledges the National Cancer Institute for funding support (R01CA186769, R01CA250499). The authors thank the BRCF Microscopy Core at The University of Michigan for providing the equipment and guidance for both the 2p-PDT and TEM work. The authors also would like to thank Prof. Oren A. Scherman, Prof. Silvia Vignolini, and Dr Jade A. McCune at the University of Cambridge for providing the equipment and guidance necessary to run the aqueous gel permeation chromatography (GPC) found in the ESI† of this text.