Remote‐Controlled Release of Singlet Oxygen by the Plasmonic Heating of Endoperoxide‐Modified Gold Nanorods: Towards a Paradigm Change in Photodynamic Therapy

Abstract

The photodynamic therapy of cancer is contingent upon the sustained generation of singlet oxygen in the tumor region. However, tumors of the most metastatic cancer types develop a region of severe hypoxia, which puts them beyond the reach of most therapeutic protocols. More troublesome, photodynamic action generates acute hypoxia as the process itself diminishes cellular oxygen reserves, which makes it a self-limiting method. Herein, we describe a new concept that could eventually lead to a change in the 100 year old paradigm of photodynamic therapy and potentially offer solutions to some of the lingering problems. When gold nanorods with tethered endoperoxides are irradiated at 808 nm, the endoperoxides undergo thermal cycloreversion, resulting in the generation of singlet oxygen. We demonstrate that the amount of singlet oxygen produced in this way is sufficient for triggering apoptosis in cell cultures.

Molecular devices based on reversible singlet oxygen binding in optical and photomedical applications

“…62 The target molecular system involved 9,10-diphenylanthracene EPO attached to the surface of gold nanorods through thiol linkers. Spectroscopic data revealed that each GNR carried approximately 6.5 × 10 9 endoperoxide molecules.…”

A nanoliposome-based photoactivable drug delivery system for enhanced cancer therapy and overcoming treatment resistance

“…24 PDT has been developed in past decades, it is a promising modality for the management of various tumors and nonmalignant diseases, based on the application of photosensitizer (PS) and activated by a specific wavelength of light and resulted in photo damage and subsequent cell death via generating a lot of reactive oxygen species (ROS; such as hydrogen peroxide, hydroxyl radicals, and super oxides). [25][26][27] Herein, we report photo-activated nanoliposomes (PNLs) that impart photocytotoxicity to multiple tumor compartments and reversal of MDR and enable photoinitiated, rapid release of antitumor drugs ( Figure 1). As schemed in Figure 1, doxorubicin (DOX) was encapsulated in the hydrophilic inner chamber of nanoliposome, and a PS hematoporphyrin monomethyl ether (HMME) was embed in the phospholipid layer of nanoliposome.…”

Intermolecular Structural Change for Thermoswitchable Polymeric Photosensitizer

“…1 Many types of PS and PS-nanocarriers have been developed to overcome those limitations. 4 Integration with other oncologic interventions such as thermal therapies has been considered for synergistic photo cancer therapies. 5 …”

“…4d,9 Various polymeric PS responding to internal and external stimuli such as pH, 10 enzymes, 11 and nucleic acid 12 have been actively studied. To this goal, conjugation of PS with thermosensitive polymers is an attractive strategy since it can improve PS solubility, control photoactivity, and enable combining PDT with thermal therapies.…”