Cheap and harmless
Biocompatible Gold Nanoparticles for Cancer diagnosis and treatment
An international group of researchers, which includes specialists from NUST MISIS and Clemson University (Clemson University, Clemson, USA), reports on a new method for producing gold nanoparticles based on synthesis under the influence of ultraviolet light. The technology excludes the use of aggressive chemical agents, the resulting nanoparticles are safe for the body and can be used for the diagnosis and therapy of oncological diseases.
An article describing the new method was published in the journal Biomaterials Science (Attia et al., In situ preparation of gold–polyester nanoparticles for biomedical imaging).
Oncological diseases are one of the most common causes of death. The search continues for ways to diagnose and treat cancer, including using nanotechnology.
Gold nanoparticles are used in the process of catalysis, in electronics, solar cells, and they are of great interest from the point of view of biomedicine. Their important advantage is the presence of properties necessary for the so–called bioimaging, that is, detailed diagnosis of the tumor and subsequent therapy.
As agents for bioimaging, gold nanoparticles are usually used in computed tomography. Tumor therapy using gold nanoparticles can be carried out due to the so-called photothermal therapy, when the particles first accumulate in the tumor, and then warm up under the influence of an external field and destroy cancer cells.
At the same time, existing methods for producing gold nanoparticles usually require the use of sufficiently aggressive chemical agents, which makes their further use in biomedicine difficult, or require several stages of synthesis, which increases the cost of production.
The new method of producing gold nanoparticles is more "ecological". The HAuCl4 gold salt is mixed with a copolymer composed of: polylactic acid-polyethylene glycol in the presence of polyvinyl alcohol and a special Irgacure photoinitiator.
The technology excludes the use of aggressive substances and chemical agents that are toxic to a living organism.
"Despite the long and slightly frightening list of components, they are all highly biocompatible and are actively used in biomedicine," explained one of the co–authors of the work, a researcher at the laboratory of Biomedical Nanomaterials at NUST MISIS, PhD Roman Akasov. – The resulting mixture is mixed under the action of ultrasound, forming a double emulsion of water-oil-water. Then it can be irradiated with ultraviolet light, resulting in the formation of gold nanoparticles in the solution. In this case, the particles are surrounded by a polymer, which gives them the properties of biocompatibility and stability in aqueous solutions. At the same time, the emulsion turns from whitish-transparent to red, which is an indicator of successful photopolymerization. The particle size in our experiments was about 100 nanometers, which is attractive for biomedical applications, and the particles were not toxic to cells."
The authors also managed to show that gold nanoparticles accumulate in the cytoplasm of cells – both tumor glioma and immune macrophage cells. This opens up the possibility of individual diagnosis and therapy of tumor diseases. In the future, it is planned to modify the surface of the nanoparticles with special molecules in order to target the tumor in the body. However, the researchers suggest another way to use the method – as a bioconstructor.
The resulting emulsions can be injected into a cell or even an organism even before the photopolymerization stage – the process of polymer synthesis under the influence of light – and synthesized into gold nanoparticles directly in the tissue under study. At the same time, the properties of the obtained nanoparticles will be able to judge the features of the living environment in which they are located, which can be an important tool for studying the biology of the cell and the processes that occur in it.
At the moment, the group continues a series of laboratory experiments within the preclinical stage of research.
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