Photodynamic therapy, an innovative technique for the treatment of tumors oìand other types of lesions, acquired a lot of interest in the research field for its advantages with respect to more traditional therapies as radiotherapy and chemotherapy. However, since this technique is quite recent, it is still premature to be applied to a clicnical use on a large scale. Indeed, even if this therapy is really promising, its full potential is still to be developed. Hence, lots of efforts have been made by researchers to increase its efficacy. In particular, the use of metallic nanoparticle has been proposed for their plasmonic properties, since they result to be very efficient in the enhancement of the absorbption of a fundamental component of photodynamic therapy, the photosensitizer. This latter is a molecule or a compound that is able to absorb inident light an start a series of reactions that lead to the formation of singlet oxygen, a product that is obtained from the oxygen present in the cells and that is highly cytotoxic. Photodynamic therapy is mainly based on the production of singlet oxygen to obtain the death of tumoral cells, and it has been experimentally demonstrated that the use of metallic nanoparticles, by increasing the photosensitizer absorption, leads to an enhancement of the generation of this product. The increase of absorption by the photosensitizer is maximum when the spectral position of its peak of absorption and of the peak of plasmonic resonance of the nanoparticle coincide. The aim of this thesis is to engineer metallic nanoparticles of different shapes and sizes to obtain this superposition, and in particular to understand how the spectral position of the plasmonic resonance peak of a nanoparticle varies depending on its shape and size. Several photosensitizers will be studied and for each of them different nanoparticles will be simulated, showing for which of them we have a superposition of the resonance and absorption peaks. Moreover, the effective enhancement of the photosensitizer absorption in presence of the metallic nanoparticle is going to be evaluated, in order to understand which structures shapes and size are more effective.
La terapia fotodinamica, un'innovativa tecnica per il trattamento di tumori o altro tipo di lesioni, ha acquisito notevole interesse nell'ambito della ricerca per i suoi innumerevoli vantaggi rispetto alle più classiche radioterapie e chemioterapie. Tuttavia, essendo ancora una tecnica relativamente recente, è ancora a uno stadio prematuro per essere portata a un utilizzo clinico su larga scala. Infatti, per quanto questa terapia risulti estremamente promettente, non ne è stato ancora sviluppato l'intero potenziale, dunque sono stati fatti notevoli sforzi da parte dei ricercatori per il miglioramento della sua efficienza. In particolare, è stato proposto l'utilizzo di nanoparticelle metalliche per le loro proprietà plasmoniche, che risultano efficaci nell'aumentare l'assorbimento da parte di un fondamentale componente della terapia fotodinamica, il fotosensibilizzatore. Quest'ultimo è una molecola o un composto in grado di assorbire la luce incidente e dare inizio a una serie di reazioni che portano alla formazione dell'ossigeno singoletto, un prodotto ottenuto dall'ossigeno presente nelle cellule che altamente citotossico. La terapia fotodinamica si basa proprio sulla produzione di ossigeno singoletto per ottenere la morte delle cellule tumorali, ed è stato dimostrato sperimentalmente che l'utilizzo di nanoparticelle metalliche, aumentando notevolmente l'assorbimento da parte del fotosensibilizzatore, porta a un incremento della creazione di questo prodotto. L'aumento dell'assorbimento da parte del fotosensibilizzatore è massimo quando la posizione spettrale del suo picco di assorbimento e quella del picco di risonanza plasmonica della nanoparticella coincidono. Lo scopo di questa tesi è di ingegnerizzare nanoparticelle metalliche di varie forme e dimensioni per ottenere questa sovrapposizione, e in particolare di capire come la posizione spettrale del picco di risonanza plasmonica di una nanoparticella varia a seconda della sua forma e della sua dimensione. Diversi fotosensibilizzatori saranno studiati e per ognuno di essi diverse nanoparticelle saranno simulate, mostrando per quali si ha una sovrapposizione dei picchi di risonanza e di assorbimento. Inoltre sarà valutato l'incremento effettivo dell'assorbimento in presenza della nanoparticella metallica, per valutare quali strutture e quali dimensioni sono maggiormente efficaci.
Miglioramento dell'efficienza della terapia fotodinamica tramite ingegnerizzazione di nanostrutture plasmoniche
CENCINI, AURA
2021/2022
Abstract
Photodynamic therapy, an innovative technique for the treatment of tumors oìand other types of lesions, acquired a lot of interest in the research field for its advantages with respect to more traditional therapies as radiotherapy and chemotherapy. However, since this technique is quite recent, it is still premature to be applied to a clicnical use on a large scale. Indeed, even if this therapy is really promising, its full potential is still to be developed. Hence, lots of efforts have been made by researchers to increase its efficacy. In particular, the use of metallic nanoparticle has been proposed for their plasmonic properties, since they result to be very efficient in the enhancement of the absorbption of a fundamental component of photodynamic therapy, the photosensitizer. This latter is a molecule or a compound that is able to absorb inident light an start a series of reactions that lead to the formation of singlet oxygen, a product that is obtained from the oxygen present in the cells and that is highly cytotoxic. Photodynamic therapy is mainly based on the production of singlet oxygen to obtain the death of tumoral cells, and it has been experimentally demonstrated that the use of metallic nanoparticles, by increasing the photosensitizer absorption, leads to an enhancement of the generation of this product. The increase of absorption by the photosensitizer is maximum when the spectral position of its peak of absorption and of the peak of plasmonic resonance of the nanoparticle coincide. The aim of this thesis is to engineer metallic nanoparticles of different shapes and sizes to obtain this superposition, and in particular to understand how the spectral position of the plasmonic resonance peak of a nanoparticle varies depending on its shape and size. Several photosensitizers will be studied and for each of them different nanoparticles will be simulated, showing for which of them we have a superposition of the resonance and absorption peaks. Moreover, the effective enhancement of the photosensitizer absorption in presence of the metallic nanoparticle is going to be evaluated, in order to understand which structures shapes and size are more effective.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/31564