Optical and thermo-plasmonic properties of spherical and hollow gold nanoparticles injected in cell organelles

Abstract

The advent of nanotechnology has profoundly altered many traditional treatment approaches, due to the beneficial physicochemical and functional characteristics of gold nanoparticles (AuNPs). These gold nanostructures are attracting particular interest in a wide range of biomedical applications, such as thermotherapy, diagnostics, detection, and drug delivery. Due to their exceptional characteristics, AuNPs have long been considered as a potential means of combating cancer. These features include surface plasmon resonance (SPR), surface chemistry and multi-functionalization. In addition to targeting tissues and cancer cells, AuNPs with the ability to specifically target organelles are attracting growing interest and are seen as the next evolutionary step in nanomedicine, forming the third generation of this technology. Subcellular targeting offers unique advantages over free targeting, as it enables specific delivery of encapsulated NPs to the intracellular site of action. This translates into greater therapeutic efficacy with a reduced dose and, above all, the ability to overcome immune resistance. AuNPs act as small heat sources taking advantage of SPR phenomenon, enabling targeted heating of specific organelles. The thermoplasmonic effect disrupts organelle function in targeted cancer cells, leading to their destruction. In this work, we used the finite element method (FEM) to examine the properties associated with the SPR of both spherical and hollow AuNPs when they are embedded in the main cellular components, including the lysosome, cell membrane, mitochondria, nucleus, cytoplasm and extracellular medium. In order to predict the thermal destructive power of solid spheres (SAuNPs) and hollow (HAuNPs) gold nanoparticles embedded in these different organelles, we simulated their absorption capacity, field enhancement effect and temperature distribution. The results obtained show that the thermoplasmonic effect is very important for HAuNPs compared with SAuNPs. In addition, the optical and thermoplasmonic properties of SAuNPs and HAuNPs show differential behavior for different cell organelles.