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Researchers from the National laboratory of Sincrotron Light (LNLS), Biosciences (LNBio) and Nanotechnology (LNNano) are developing a technology based in nanoparticles so that chemotherapeutic drugs can reach specifically at cancer cells, causing less damage to healthy cells in the body. The research developed in partnership between scientists from Universidade Estadual de Campinas (Unicamp) was developed in LNLS.

The majority of drugs used in cancer chemotherapy affects the process of cell division. Although the uncontrolled cell division is one of the main characteristic of tumors, healthy cells also divide themselves, and for that reason they end up suffering with the effect of the drugs which, once applied, they spread all over the body, causing secondary effects.

The system tested by the Brazilian researchers is composed by silica nanoparticles – the same material as sand grains – coated by a certain organic molecule called “folato”. “The cancer cell expresses more folato receptors than the normal cells”, said the biologist from Unicamp, Jörg Kobarg. Due to this, the nanoparticles, which can contain the drug, will be easily absorbed by the tumor than by healthy tissue.

“We still don’t know exactly if this selection was created by the folato”, adds Kobarg. “But the particle is coated with folato and the cancer cell expresses more reaction from this, which can be an explanation. We observed that, in fact, our particle is much more toxic for the cancer cell than for the normal cell”.

Insoluble

The article published in the newspaper Langmuir, “Functionalized Silica Nanoparticles as an Alternative Platform for Targeted Drug-Delivery of Water Insoluble Drugs”, describes the action of the model over prostate cell strains, both sick and healthy. The nanoparticles coated with folato were charged with curcumina, a pigment extracted from soil saffron that is being studied as possible drug against cancer. In theory, the particles could transport any drug, including traditional medicine.

“It’s colorful [the curcumina], which is an advantage when it’s time to analyse the particles, and also insoluble in water, which is an additional advantage. Nowadays it is not used as much in treatments because, if you try to dissolve in blood, it won’t work. But we managed to insert it in particles, and the particles are soluble. It’s the nanoparticles who carry the drug”, says researcher Mateus Borba Cardoso, from LNLS, also author of the study.

According to scientists, the use of folato was just the first step. New studies will test ways to “decorate” silica as antibodies, increasing the selection of the particles by the cancer cells.

Application

The article published states the affinity of nanoparticles coated with folato by the cancer cells and its toxicity against these cells. The initial result was considered promising, but the rate of proposed techniques against the cancer, which were favorable in in vitro tests and viable as treatment, is considerably low – around 5%, according to some estimates.

“It’s a low rate, very low rate”, Cardoso recognizes. “I, particularly, believe that before we have any real test, we should improve the system a bit more, something that we are currently doing, trying to put antibodies at surface. Because the antibody with the cancer cell is like a key and a lock. So our idea is to insert antibodies in a way that only one type of cell recognizes that nanoparticle, thought the antibody, and that way the treatment is more effective”.

The National Laboratory of Sincroton Light, from the National Research in Energy and Material Centre (CPNEM) was used to analyze the nanoparticles. Sincrotron uses accelerated electrons nearly at speed of light to produce beams of penetrating radiation, capable of generating detailed images and collect data about the characteristics of the materials used.