Gold nanorods will help burn out the tumor
Rice University chemists have developed a way to embed more than 2 million gold nanorods into a single cancer cell. This achievement is a crucial step towards the development of a method of destroying tumors by local heating.
According to the head of the study, associate Professor Eugene Zubarev, the mass of breast cancer cells used in experiments increased due to nanoparticles penetrating them by about 13%. At the same time, the cells continued to function perfectly normally.
The drawings from the article in Angewandte Chemie show nanorods at the top, and a cancer cell "stuffed" with them at the bottom.
By themselves, gold nanoparticles are unable to harm the tumor, but they can accumulate the energy of the light emitted by the laser and convert it into thermal energy. However, in order to reach a temperature sufficient to destroy a living cell, a large number of nanorods are needed.
At the same time, the more nanorods are inside the cell, the lower the power of the laser used and the irradiation time can be. Unfortunately, until now, scientists have not been able to stuff living cancer cells with enough gold nanoparticles.
The main problem was the insolubility of gold nanoparticles in water. To give them solubility, researchers usually resorted to cetylthyrmethylammonium bromide (CTAB), a surfactant that is often part of hair conditioners and is one of the key components of the gold nanorods manufacturing process.
CTAB envelops the surface of gold nanoparticles and makes them soluble in water, just as soap dissolves fat droplets during washing dishes. CTAB also gives a positive charge to the surface of nanoparticles, which promotes their penetration into living cells. However, the use of this complex in medical practice is impossible due to its toxicity. It is believed that the cause of this toxicity is a weak connection between the surface of nanoparticles and CTAB molecules, a certain amount of which is released into the environment.
The researchers proposed to replace the toxic CTAB with a related MTAB compound, which differs from CTAB by the presence of two additional atoms at one end of the molecule: sulfur and hydrogen. These atoms allow the compound to form strong bonds with the surface of gold nanoparticles.
In addition, scientists have developed an optimal strategy for the synthesis of MTAB and the enrichment and purification process, as a result of which gold nanorods are covered with a layer of MTAB, and all residual amounts of CTAB are removed from the solution containing them.
Experiments on cells have brought very encouraging results; the authors plan to test the approach they developed on animal models and, eventually, conduct clinical studies with the participation of cancer patients.
Article by Leonid Vigderman et al. Quantitative Replacement of Cetyl Trimethylammonium Bromide by Cationic Thiol Ligands on the Surface of Gold Nanorods and Their Extremely Large Uptake by Cancer Cells is published in the journal Angewandte Chemie International Edition.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Rice University:
Rice chemists cram 2 million nanorods into single cancer cell.
18.11.2011