skip to main content

Title: Photooxidative Vulnerability to Intralipid in Photodynamic Therapy
This chapter is intended to help make inroads to the role of Intralipid in photodynamic therapy (PDT). In addition to Intralipid’s favorable property as a light scattering agent, we hypothesized that it will be unstable to photosensitized oxidation. To explore this, measurements of total quenching rate constants (kT) of singlet oxygen with Intralipid and its constituents are described. Furthermore, organic phosphines were tested to trap Intralipid peroxides formed in photosensitized oxidation reactions. Our findings indicate that the vulnerability of Intralipid to photooxidation might suggest limits of its use in PDT.
Authors:
; ; ; ; ; ; ; ;
Editors:
Protti, S.; Raviola, C.
Award ID(s):
1856765
Publication Date:
NSF-PAR ID:
10230578
Journal Name:
Photochemistry
Volume:
48
Page Range or eLocation-ID:
411-422
ISSN:
0556-3860
Sponsoring Org:
National Science Foundation
More Like this
  1. The title compound, bis(1,2-diphenyl-2-sulfanylideneethanethiolato-κ 2 S , S ′)(1,3,5-triaza-7-phosphaadamantane-κ P )cobalt(II) dichloromethane hemisolvate, [Co(pdt) 2 (PTA)]·0.5C 2 H 4 Cl 2 or [Co(C 14 H 10 S 2 ) 2 (C 6 H 12 N 3 P)]·0.5C 2 H 4 Cl 2 , contains two phenyldithiolene (pdt) ligands and a 1,3,5-triaza-7-phosphaadamantane (PTA) ligand bound to cobalt with the solvent 1,2-dichloroethane molecule located on an inversion center. The cobalt core exhibits an approximately square-pyramidal geometry with partially reduced thienyl radical monoanionic ligands. The supramolecular network is consolidated by hydrogen-bonding interactions primarily with nitrogen, sulfur and chlorine atoms, as well as parallelmore »displaced π-stacking of the aryl rings. The UV–vis, IR, and CV data are also consistent with monoanionic dithiolene ligands and an overall Co II oxidation state.« less
  2. The use of nanoparticle-based materials to improve the efficacy of photodynamic therapy (PDT) to treat cancer has been a burgeoning field of research in recent years. Polysilsesquioxane (PSilQ) nanoparticles with remarkable features, such as high loading of photosensitizers, biodegradability, surface tunability, and biocompatibility, have been used for the treatment of cancer in vitro and in vivo using PDT. The PSilQ platform typically shows an enhanced PDT performance following a cell death mechanism similar to the parent photosensitizer. Ferroptosis is a new cell death mechanism recently associated with PDT that has not been investigated using PSilQ nanoparticles. Herein, we synthesized amore »protoporphyrin IX (PpIX)-based PSilQ platform (PpIX-PSilQ NPs) to study the cell death pathways, with special focus on ferroptosis, during PDT in vitro. Our data obtained from different assays that analyzed Annexin V binding, glutathione peroxidase activity, and lipid peroxidation demonstrate that the cell death in PDT using PpIX-PSilQ NPs is regulated by apoptosis and ferroptosis. These results can provide alternative approaches in designing PDT strategies to enhance therapeutic response in conditions stymied by apoptosis resistance.« less
  3. A strategy to generate crystalline coordination polymers with strong, covalent metal-linker bonds is presented. 1,6-Pyrenedi(2-ethylhexylmercaptopropionate) ( 1 ) is converted to 1,6-pyrenedithiolate (PDT) via a base-mediated deprotection allowing for rate control of the metal-linker self assembly. This leads to the formation of a single-crystalline, flexible 2D coordination polymer, [Cd(PDT) 2 ][Cd(en) 3 ] ( 3 ).
  4. Sundowner winds are downslope gusty winds often observed on the southern slopes of the Santa Ynez Mountains (SYM) in coastal Santa Barbara (SB), California. They typically peak near sunset and exhibit characteristics of downslope windstorms through the evening. They are SB’s most critical fire weather in all seasons and represent a major hazard for aviation. The Sundowner Winds Experiment Pilot Study was designed to evaluate vertical profiles of winds, temperature, humidity, and stability leeward of the SYM during a Sundowner event. This was accomplished by launching 3-hourly radiosondes during a significant Sundowner event on 28–29 April 2018. This study showedmore »that winds in the lee of the SYM exhibit complex spatial and temporal patterns. Vertical profiles showed a transition from humid onshore winds from morning to midafternoon to very pronounced offshore winds during the evening after sunset. These winds accompanied mountain waves and a northerly nocturnal lee jet with variable temporal behavior. Around sunset, the jet was characterized by strong wind speeds enhanced by mountain-wave breaking. Winds weakened considerably at 2300 PDT 29 April but enhanced dramatically at 0200 PDT 29 April at much lower elevations. These transitions were accompanied by changes in stability profiles and in the Richardson number. A simulation with the Weather Research and Forecasting (WRF) Model at 1-km grid spacing was examined to evaluate the skill of the model in capturing the observed winds and stability profiles and to assess mesoscale processes associated with this event. These results advanced understanding on Sundowner’s spatiotemporal characteristics and driving mechanisms.

    « less
  5. Photoactive agents are promising complements for both early diagnosis and targeted treatment of cancer. The dual combination of diagnostics and therapeutics is known as theranostics. Photoactive theranostic agents are activated by a specific wavelength of light and emit another wavelength, which can be detected for imaging tumors, used to generate reactive oxygen species for ablating tumors, or both. Photodynamic therapy (PDT) combines photosensitizer (PS) accumulation and site-directed light irradiation for simultaneous imaging diagnostics and spatially targeted therapy. Although utilized since the early 1900s, advances in the fields of cancer biology, materials science, and nanomedicine have expanded photoactive agents to modernmore »medical treatments. In this review we summarize the origins of PDT and the subsequent generations of PSs and analyze seminal research contributions that have provided insight into rational PS design, such as photophysics, modes of cell death, tumor-targeting mechanisms, and light dosing regimens. We highlight optimizable parameters that, with further exploration, can expand clinical applications of photoactive agents to revolutionize cancer diagnostics and treatment.« less