Novel polyoxometalate composites for targeted drug delivery and photothermal therapy

• Autor(a) principal: Faria, Fátima Gabriela Guedes
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/28070
• topic: Hydrogels; PH; Photothermal therapy; Polyoxometalates; Responsive systems; Targeted delivery; Temperature

In the last decades, hydrogels have attracted great interest in biomedical applications, namely as systems for targeted and controlled release of therapeutic molecules. One of the most exciting properties of hydrogels is their tunability to respond to several stimuli, such as pH, temperature, and ion concentration. In therapeutic release, this is a key feature since it enables a release triggered/ controlled by specific stimuli. Among the hydrogels, injectable and self-healing hydrogels gained special attention due to its minimally invasive character and ability to fit the target easily. Photothermal therapy is an emerging treatment methodology known to be highly effective, selective, minimally invasive and able to eliminate several types of cancers. Aiming the synergistic association of both targeted and controlled release and photothermal therapy, this thesis explores the development of a chitosan copolymer (CS-g-PNIPAAm) hydrogel incorporating the polyoxometalate {Mo154} as photothermal conversion agent. The prepared hydrogel showed fast self-healing and injectability, as well as pH and temperature-responsiveness in the release of two distinct cargo molecules: doxorubicin and horseradish peroxidase. In addition, the developed hydrogel demonstrated to have an enhanced photothermal conversion ability when compared to a {Mo154} aqueous solution, causing a temperature increase of around 35 ºC with low irradiance (0.1 or 0.82 W/cm2 with an excitation wavelength of 785 or 808 nm, respectively). Overall, the composite described herein can be used in applications needing a dual combination therapy, i.e., simultaneous drug and photothermal therapy, delivered through an injectable hydrogel where in situ administration is needed.