Nanopartículas de ouro ultrapequenas e nanoclusters luminescentes: estudos sistemáticos na interface nano-bio
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Data
2024-02-19
Autores
Lima, André Ferreira [UNIFESP]
Orientadores
Sousa, Alioscka Augusto Caldeira Araujo [UNIFESP]
Tipo
Dissertação de mestrado
Título da Revista
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Resumo
Nanopartículas de ouro (GNPs) ultrapequenas apresentam imenso potencial em aplicações biomédicas. Seu tamanho reduzido (< 3 nm) possibilita que esses nanomateriais interajam com proteínas de forma transiente, ou seja, sem a formação de uma camada de adsorção estável (corona proteica), como observado para GNPs convencionais de maior tamanho. Outro aspecto interessante relacionado ao seu tamanho é a possibilidade de eliminação in vivo pela via de excreção renal. Apesar do amplo potencial de aplicações das GNPs ultrapequenas, ainda existe uma lacuna significativa na compreensão do impacto dessas partículas em proteínas e células, um conhecimento crucial para aplicações in vivo. Neste contexto, produzimos diferentes modelos de GNPs ultrapequenas e analisamos os efeitos de suas interações com proteínas e células. O primeiro modelo consistiu de GNPs ultrapequenas aniônicas com um núcleo de ouro de ~2 nm. Essas partículas foram avaliadas quanto ao seu impacto sobre a estrutura e função de proteínas ao longo do tempo. Observamos que elas promoveram alterações funcionais reversíveis nas proteínas após um curto período de interação (10 min), mas irreversíveis após um período prolongado (24 h). Surpreendentemente, essas alterações funcionais não foram acompanhadas por mudanças conformacionais globais relevantes. O segundo modelo de GNPs ultrapequenas consistiu em nanoclusters de ouro fotoluminescentes, estabilizados com glutationa (caráter aniônico) e duas outras variantes (zwitteriônica e catiônica) dessa molécula. Os nanoclusters foram avaliados quanto à manutenção da luminescência sob diferentes condições de incubação, bem como investigados em relação às suas interações com proteínas e células. Como resultado, os nanoclusters demonstraram excelente estabilidade coloidal. Além disso, exibiram luminescência constante em diferentes pHs, porém mostraram-se sensíveis a variações de viscosidade e temperatura. Em relação às interações com proteínas, observou-se uma interação fraca, e a viabilidade celular não foi significativamente impactada. Tomados em conjunto, esses resultados fornecem informações importantes para entender o comportamento e os efeitos de GNPs ultrapequenas em ambientes fisiológicos.
Ultrasmall gold nanoparticles (GNPs) show immense potential in biomedical applications. Their reduced size (< 3 nm) allows these nanomaterials to interact with proteins transiently, that is, without the formation of a stable adsorption layer (protein corona), as observed for larger conventional GNPs. Another interesting aspect related to their size is the possibility of elimination in vivo via renal excretion. Despite the broad potential applications of ultrasmall GNPs, there is still a significant gap in understanding the impact of these particles on proteins and cells, an essential knowledge for in vivo applications. In this context, we generated different models of ultrasmall GNPs in this study and examined the impact of their interactions with proteins and cells. The first model consisted of ultrasmall anionic GNPs with a ~2 nm gold core. These particles were evaluated for their impact on protein structure and function over time. We observed that they promoted reversible functional changes in proteins after a short period of interaction (10 min), but irreversible changes after a prolonged period (24 h). Surprisingly, these functional changes were not accompanied by relevant global conformational modifications. The second model of ultrasmall GNPs consisted of luminescent gold nanoclusters, stabilized with glutathione (anionic character) and two other variants (zwitterionic and cationic) of this molecule. The nanoclusters were assessed for the stability of luminescence under different incubation conditions and investigated for their interactions with proteins and cells. The results revealed that the nanoclusters demonstrated excellent colloidal stability. Furthermore, they exhibited constant luminescence at different pHs, but were sensitive to variations in viscosity and temperature. Regarding interactions with proteins, a weak interaction was observed, and cell viability was not significantly impacted. Taken together, these results provide important information for understanding the behavior and effects of ultrasmall GNPs in physiological environments.
Ultrasmall gold nanoparticles (GNPs) show immense potential in biomedical applications. Their reduced size (< 3 nm) allows these nanomaterials to interact with proteins transiently, that is, without the formation of a stable adsorption layer (protein corona), as observed for larger conventional GNPs. Another interesting aspect related to their size is the possibility of elimination in vivo via renal excretion. Despite the broad potential applications of ultrasmall GNPs, there is still a significant gap in understanding the impact of these particles on proteins and cells, an essential knowledge for in vivo applications. In this context, we generated different models of ultrasmall GNPs in this study and examined the impact of their interactions with proteins and cells. The first model consisted of ultrasmall anionic GNPs with a ~2 nm gold core. These particles were evaluated for their impact on protein structure and function over time. We observed that they promoted reversible functional changes in proteins after a short period of interaction (10 min), but irreversible changes after a prolonged period (24 h). Surprisingly, these functional changes were not accompanied by relevant global conformational modifications. The second model of ultrasmall GNPs consisted of luminescent gold nanoclusters, stabilized with glutathione (anionic character) and two other variants (zwitterionic and cationic) of this molecule. The nanoclusters were assessed for the stability of luminescence under different incubation conditions and investigated for their interactions with proteins and cells. The results revealed that the nanoclusters demonstrated excellent colloidal stability. Furthermore, they exhibited constant luminescence at different pHs, but were sensitive to variations in viscosity and temperature. Regarding interactions with proteins, a weak interaction was observed, and cell viability was not significantly impacted. Taken together, these results provide important information for understanding the behavior and effects of ultrasmall GNPs in physiological environments.