Phototermal therapy using gold nanoparticles

• Autor(a) principal: Rodriguez Lopez, António Guevara Ferreira Exposto
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/28735
• topic: Cancer; Nanotechnology; Photothermal therapy; Gold nanoparticles; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Cancer is one of the leading causes of mortality worldwide. The fact that most people do not actually die from the cancer itself, but from the side effects of the conventional treatments (e.g. chemotherapy and radiation) has led scientists to find new therapies that can surpass the problem with lack of selectivity and specificity. Nanotechnology is Cancer is one of the leading causes of mortality worldwide. The fact that most people do not actually die from the cancer itself, but from the side effects of the conventional treatments (e.g. chemotherapy and radiation) has led scientists to find new therapies that can surpass the problem with lack of selectivity and specificity. Nanotechnology is still a field in development but it could overcome these problems. It offers great potential in the biomedical field, in imaging, diagnostics, and therapy. Photothermal therapy uses light to induce heat that leads to cell death. Cancer cells have proven to be more vulnerable to increase of heat due to poor blood supply and lack of heat dissipation. Generally this therapy employs near infrared radiation, which allows deep tissue penetration, thus allowing the evasion of absorbance of biomolecules (e.g. hemoglobin). Comparing conventional therapeutic modalities, photothermal therapy shows unique advantages in cancer therapy including high selectivity and specificity, and minimal invasiveness. Gold nanoparticles possess unique optical, electronic and thermal properties for photothermal therapy. Moreover, they are easy to synthetize in aqueous media and can be easily functionalized with a wide range of biomolecules. Modulating the geometric and physical parameters of nanostructures such as shape and size, the plasmon resonance peaks of gold nanoparticles could be tuned to the near-infrared region or the visible region. By using light radiation with a frequency that strongly overlaps the nanoparticle plasmon absorption band, the aim is that the photothermal conversion procedure could be highly efficient. The purpose of this work was to perform a photothermal characterization of gold nanoparticles with different sizes with the perspective of downstream application to photothermal ablation of cancer cells. Synthesis and functionalization of gold nanoparticles with different sizes were performed successfully. Using calorimetry it was concluded that “PEGylated” gold nanoparticles have higher photothermal conversion capacities than the ones with a citrate capping, and that smaller gold nanoparticles are more efficient in converting light to heat than the bigger ones.still a field in development but it could overcome these problems. It offers great potential in the biomedical field, in imaging, diagnostics, and therapy. Photothermal therapy uses light to induce heat that leads to cell death. Cancer cells have proven to be more vulnerable to increase of heat due to poor blood supply and lack of heat dissipation. Generally this therapy employs near infrared radiation, which allows deep tissue penetration, thus allowing the evasion of absorbance of biomolecules (e.g. hemoglobin). Comparing conventional therapeutic modalities, photothermal therapy shows unique advantages in cancer therapy including high selectivity and specificity, and minimal invasiveness. Gold nanoparticles possess unique optical, electronic and thermal properties for photothermal therapy. Moreover, they are easy to synthetize in aqueous media and can be easily functionalized with a wide range of biomolecules. Modulating the geometric and physical parameters of nanostructures such as shape and size, the plasmon resonance peaks of gold nanoparticles could be tuned to the near-infrared region or the visible region. By using light radiation with a frequency that strongly overlaps the nanoparticle plasmon absorption band, the aim is that the photothermal conversion procedure could be highly efficient. The purpose of this work was to perform a photothermal characterization of gold nanoparticles with different sizes with the perspective of downstream application to photothermal ablation of cancer cells. Synthesis and functionalization of gold nanoparticles with different sizes were performed successfully. Using calorimetry it was concluded that “PEGylated” gold nanoparticles have higher photothermal conversion capacities than the ones with a citrate capping, and that smaller gold nanoparticles are more efficient in converting light to heat than the bigger ones.