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Serbian Scientists Have Been Studying a New Way for Production of Biomedical Nano-Gold Particles

The research team from the Faculty of Medicine, the University of Nis, headed by academician Miodrag Colic, in cooperation with European partners, has designed and developed a new method for the synthesis and biological evaluation of nanoparticles made ​​of recycled gold jewelry.

Gold nanoparticles are increasingly used, both in various fields of modern science and technology (in tumor detection, the search for oil) and in everyday life (a variety of artistic techniques, even in street lighting). Their clinical use in medicine is previously known in treating arthritis. Gold nanoparticles were also studied and applied to the treatment of bronchial asthma, malaria and Chagas disease, and their activity and the effects on the HIV virus and tumors have recently been tested. In dentistry they can be used for corrective interventions on the tooth surface, to fill pockets between teeth, and for the production of implants for tooth replacement.

Few chemical methods for producing nano-gold particles have been developed so far, but the use of toxic chemicals during production proved itself to be major problem. Applying these methods, the reductive chemicals that are cytotoxic at high concentrations are being introduced into the solution of nanoparticles, which prevents their use in medicine. Ultrasonic spray pyrolysis (USP) is an innovative and green technology used to produce different types of nano-sized powders. An international research team, headed by academician Miodrag Colic, was the first who managed to synthesize nano-gold particles using recycled gold jewelry as the initial raw material and by using USP technology. The studies were implemented under the Eureka project E! 4953 GONano – Synthesis of gold nano-particles for dental/medical applications in collaboration with European partners: RWTH Aachen University, Germany, and the Faculty of Mechanical Engineering, University of Maribor and the company Zlatarna Celje, Slovenia.

“By using recycled gold as a starting material for the synthesis of pure nano-gold particles, the efficiency of the whole process is significantly improved and the production of nanoparticles becomes much less expensive”, says academician Colic.

From Old Jewelry to Drug Carriers

Both pure gold and recycled gold jewelry were used as a raw material for synthesis of biomedical nanoparticles. Using USP, researchers from Nis have managed to synthesize nanoparticles with clean composition (pure gold), but also those contaminated with metals from the starting materials (Cu, Zn, Fe, In, etc.).

One of the key project goals was to prove biocompatibility, and to research the immunomodulatory potential of nanoparticles obtained by applying the new method, as these are significant factors for developing new, functionalized, nano-gold particles intended to be used in human and veterinary medicine (nano-gold particles conjugated with drugs, biological modifiers, enzymes, etc.).

Tests have shown that nanoparticles of pure gold (sizes from 50 to 150 nm) do not express cytotoxic effects on various cell lines, even at high concentrations (up to 100 mg / ml) and after a prolonged activity in the cell culture (3 days). However, the nanoparticles with alloying elements such as Zn, Cu, Ni, etc. have proven to be cytotoxic to rat tymocytes and splenocytes, and L929 mouse fibroblast lines. Also, it was shown that smaller nanoparticles made of pure gold have more pronounced immunosuppressive effects than larger nanoparticles due to effects of higher ultrasonic frequencies.

The results of previous research have been published in the Journal of Biomedical Application1 and Journal of Biomedical Nanotechnology2, and were presented at two international conferences: in Sibiu, Romania (April, 2010), and in Split, Croatia (July, 2011).

The next goal of academician Colic’s research team is conjugation of obtained nano-gold particles with polypeptide carriers that would transport the immunomodulatory agents to the dendritic cells that are key initiators, coordinators and controllers of innate and acquired immunity. These cells are particularly suitable for creating new therapeutic procedures in the treatment of cancer or autoimmune diseases.

“It is expected that the results of researched effects of nano-gold particles on immune system cells will clarify some of the uncertainties related to the mechanism of the particles’ action and their possible use as drug carriers. This would have a significant impact on the scientific field of nanobiotechnology and nanomedicine, especially on the development of anti-tumor vaccines with activated dendritic cells”, says academician Colic.

 

Source: www.inovacionifond.rs