Ga Ion-Enhanced and Particle Shape-Dependent Generation of Reactive Oxygen Species in X-ray-Irradiated Composites

Abstract

The reported results test the effects of the collective behavior hypothesized to contribute to the production of more reactive oxygen species (ROS) in vitro and result in an enhanced radiosensitization. The role of particle shape in composites with gallium oxyhydroxide (GaOOH) particles and Matrigel is studied. Particles of two different shapes are embedded into the gel to understand only the materials effect on the generation of ROS rather than cell penetrating variations. The paper reports materials characterization by scanning electron microscopy and X-ray diffraction. The stability of the particles within the composite is assessed by quantification of leached metal using inductively coupled plasma mass spectrometry. The amount of ROS in each construct under variable radiation conditions is quantified in the presence and absence of PC12 cells seeded on top of the composites. The viability of cells is also recorded under different in vitro conditions. The collective materials characterization and the results from the bioassays are used to explain the role of anisotropy on the radiosensitization of nanostructures containing Ga. The presence of Ga ions in composites can have a radiosensitizing effect, and the amount of the available Ga3+ determines the magnitude of the radiosensitization. The shape of the particles determines the stability in aqueous solutions and release of Ga3+ that triggers ROS production. The concentration and shape of Ga-containing materials can be combined to generate an additive effect by increasing the amount of available free metal ions in solution. The studies with GaOOH containing composites enable one to explore the role of key parameters that lead to an increased efficiency of radiation treatments.

Mechanisms for Tuning Engineered Nanomaterials to Enhance Radiation Therapy of Cancer

“…[184] Other authors have also suggested a more efficient electron emission from smaller NPs, since the excited electrons have a lower probability of dissipating their energy inside the NP before reaching the surface. [227] The effects of NP shape on ROS generation, also widely observed, [228] and they can be attributed to a different mix of crystalline orientations with varying chemical activity. The effect of this orientation on the emission of electrons and reactive species generation is well established, for example, in water splitting by atanase and rutile TiO 2 NPs whose crystalline surface ordering differ.…”

Chemical Mechanisms of Nanoparticle Radiosensitization and Radioprotection: A Review of Structure-Function Relationships Influencing Reactive Oxygen Species

“…A stable dispersion of metal nanoparticles is important for many biological applications and is dependent on nanoparticle shape and surface chemistry. While stable nanoparticles are preferential in biological studies due to biocompatibility [139], some studies suggest that a slight aggregation of nanoparticles increases cell uptake [102,120,150], Adams et al found the shape of gallium oxyhydroxide nanoparticles was influential on stability and thus on the generation of ROS. Their anisotropic shaped nanoparticles were found to be unstable in aqueous solutions and released gallium ions, leading to an increase in ROS generation, unlike the "orzo" shaped nanoparticle of the same surface chemistry [102].…”

Nano‐Biomedicine based on Liquid Metal Particles and Allied Materials

“…[ 63 ] GaOOH is demonstrated to be related with the generation of reactive oxygen species (ROS) in radiosensitization. [ 76,77 ] LMNPs can enable different shapes and composition, including sphere shape, rice shape, and rod shape (Figure 2d,e). [ 50,78 ] Several positive‐charged surfactants, such as cetrimonium bromide or lysozyme, are demonstrated to enable the shape morphing process upon heating, and the indium nanoparticles can be dealloyed as the by‐product.…”