MIPT: Polymeric Submicrocapsules with Gold Nanoparticles for Targeted Oncotherapy

The main articles are:

• Cancer (cancer)
• Cancer treatment
• Nanoparticles in medicine

2024: Creation of polymer submicrocapsules with gold nanoparticles

Physicists MIPT have created polymeric submicrocapsules with, nanoparticles gold which, under the influence of light, are able to convert intracellular hydrogen peroxide into molecular oxygen. This allows you to start the process of cancer cell death. This effect can be applied to address. therapy of malignant tumors The results of the Clover study are published in the journal PARTICLE&PARTICLE SYSTEMS CHARACTERIZATION. This was announced on August 1, 2024 by representatives of the Moscow Institute of Physics and Technology.

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As reported, nanozymes are artificial enzymes that are nanoparticles of various chemical nature. It is easier to produce and use them in comparison with natural compounds, and in their properties they are not inferior to natural analogues.

Gold nanoparticles (AuNP) are used to mimic the enzymes peroxidase, glucose oxidase, lactate oxidase, superoxide dismutase, and catalase. The latter converts intracellular hydrogen peroxide into molecular oxygen. This and other reactive oxygen species affect the cell and disrupt its life cycle. This process is called oxidative stress.

Thus, gold nanoparticles are thought to enhance the overall efficacy of photodynamic therapy in the treatment of cancers. However, there is a problem - enzyme-like activity of nanoparticles decreases rapidly in biological environments due to aggregation (particle adhesion) and the formation of the so-called "protein corona."

MIPT scientists, together with colleagues from ITMO and Skoltech, systematized polymeric submicrocapsules of gold in terms of physicochemical and catalytic properties. As proof of concept, their therapeutic potential was evaluated in vitro. The results show that polymer capsules containing AuNP and photodynamic dye exhibit an order of magnitude higher light-induced cytotoxicity (the ability of the substance to exert a toxic effect on the cell) compared to an individual photodynamic dye.

The reaction was carried out in an environment with an acidity of pH = 7.4 - this indicator is closest to physiological conditions. The self-decomposition of hydrogen peroxide at this pH is quite insignificant, while the rapid acceleration of this process is observed when gold nanoparticles are introduced into the system. As expected, the smaller particle size (3 nm) of the catalyst resulted in a greater increase in velocity compared to 30 nm particles. For further comparison of catalytic effects, the hydrogen peroxide decomposition reaction rate was calculated as a negative slope in the linear range of concentration versus time kinetic curves. For consistency for all samples described from this point, the reaction rate during the first 5 hours was used, told Ilya Zavidovsky, senior researcher at the Laboratory of Controlled Optical Nanostructures of the Center for Photonics and 2D Materials at MIPT.

Scientists have found that most nanomaterials that mimic catalase (an enzyme that neutralizes hydrogen peroxide) usually increase their activity under alkaline conditions. In this case, the adsorption of hydrogen-containing gas peroxide is particularly effective.

Also in the course of experiments, scientists found that regardless of the surface area on which the reaction occurs, catalase-like activity increases with pH growth. For further experiments, two pH values were chosen: 7.4 to mimic physiological conditions and 7.0 as the closest to the cancer cell medium. The project team's immediate plans are to integrate MRI-contrast particles into the system under study in order to be able to control the location of photoactivated particles inside the body.