ZnO nanoparticles as a potential biolabel for bioimaging applications

• Autor(a) principal: Araújo, Luís Gonçalo Moreira
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/127911
• topic: ZnO nanoparticles; Solvothermal; Europium; Fluorescence; Bioimaging; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

In order to better understand biological processes and thus understand and find better treatments for diseases, it is essential to have suitable bioimaging methods. One of these methods is confocal mi-croscopy, which uses fluorescence. To confer fluorescence and thus study biological samples, many different types of fluorophores can be used. One of these types of fluorophores are nanoparticles, which have several advantages in compar-ison with other fluorophores. However, the nanoparticles most traditionally used for obtaining biolog-ical images use cadmium, which is very toxic. For this reason, different materials have been studied in order to conceive nanoparticles with high fluorescence and low toxicity, of which zinc oxide (ZnO) nanoparticles have generated considerable interest because, in addition to their good optical properties, these are also considered safe, being used in various areas and products such as sunscreens, cosmetics, and food packaging. Moreover, the ZnO nanoparticles are still very promising in medicine to be used in the fight against cancer and have antibacterial properties. However, as ZnO nanoparticles have a high band gap, their fluorescence mainly occurs when they are irradiated with low wavelengths, which are not commonly used in confocal microscopy or in biological samples. Due to this, throughout this thesis, ways of increasing the fluorescence of ZnO nanoparticles (by using longer wavelengths) will be studied, namely by doping them with europium, as well as the effects that different syntheses/doping concentrations influence other properties of these nanoparticles (such as morphology and crystallinity). To finalize, the fluorescence conferred to biolog-ical samples through the use of the synthesized nanoparticles will also be analyzed through confocal microscopy. The obtained results were compared with those obtained with a commercial fluorophore.