Quantum dots for photosensitization
Main aim of the project is to develop quantum dots for photosensitization of cancer cells (phototoxicity under visible light stimulus).
Since the first demonstration of the photodynamic action in 1900, great effort has been devoted towards development of agents (photosensitizers), which have specific light absorption and tissue distribution properties. Photodynamic therapy (PDT) is a treatment modality that uses such a photosensitizer, usually a porphyrin type pigment that preferentially localizes in target tissue. Absorption of a visible light photon promotes the photosensitizer molecule into its excited singlet electronic state. Intersystem crossing transfers the photosensitizer molecule into its metastable triplet state, from which photochemical reactions occur. This process leads to generation of free radicals and singlet oxygen, which is the main agent killing cancer cells.
Quantum dots possess unique optical and targeting properties offering great promise in cancer applications. So far, most of the work on quantum dots has been focused on developing them for fluorescence imaging or MRI. Next challenge is to make quantum dots work as photosensitizers.
The study is divided into following topics:
Synthesis of nanoparticles;
Uptake of nanoparticles in cancer cells in vitro;
Nanoparticle biodistribution in vivo;
Mechanisms of photosensitization (radical generation);
Dynamics of excited states.Nanoparticles for radiosensitization
Such sensitizing dots will enhance effectiveness of radiation therapy and will lower radiation doses delivered to a patient. Being tightly packed atoms, quantum dots should provide enhanced cross section for photon interaction with matter compared to that of conventional X-ray contrast agents and radiosensitizers. Depending on its energy, an incident photon will undergo different events: Rayleigh scattering, Compton scattering, photoeffects, photonuclear effects, electron ejection, electron-positron pair production, atom and nuclear recoil. After scattering the incident photon retaining part of its energy is deflected and makes further collisions. Such chain of events will lead to ion and free radical formation, chemical changes, breakage of bonds and biological effects.Combined therapy using electromagnetic radiations (gamma and visible)
Nanoparticle-photosensitizer conjugates will be tested for treatment of deeply localized tumours taking advantage of deep penetrating ability of high energy gamma photons. Upon interaction with a gamma photon, a nanoparticle will scintillate emitting a visible light photon. Such fluorescence will be absorbed by a conjugated traditional photosensitizer, which will further produce photodynamic effect.
In 2016 a new project supported by ERA-NET EuroNanomed II agency starts in collaboration with the French National Centre for Scientific Research (CNRS, Nancy), University of Hasselt (Belgium) and two French industrial partners "CyberNano" (Nancy) and "PorphyChem" (Dijon).Development of sonosensitive nanoparticles
The group has been active on this project during the period of 2006-2007. Click here to see the project's poster
The project and technology development further continues in Prof. Olsen's group here at the department in collaboration with the company Epitarget AS
(formerly CancerCure AS) sharing its activities in our labs and in the company's lab.
Since 2014 a new project in this field supported by ERA-NET EuroNanomed II agency is going on in collaboration with the University of Avignon, University of Geneva, French National Centre for Scientific Research (CNRS, Nancy) and one French industrial partner "Intelligence in Medical Technologies" (Paris).