07 December 2015

Bomb the tumor

Nanobombs will help deliver cancer drugs

Anna Obraztsova, N+1 

Researchers from Ohio State University have developed liposomal nanobombs that explode under the influence of infrared radiation. They make it possible to deliver antitumor drugs based on RNA to cancer cells. The work was published in the journal Advanced Materials (Wang et al., A Near-Infrared Laser-Activated “Nanobomb” for Breaking the Barriers to MicroRNA Delivery).

One of the ways to fight cancer cells is to change the work of genes in these cells, which will make them unviable. A variety of RNA – microRNA can be used for this. These small molecules can suppress protein synthesis from a specific gene through the process of RNA interference.

The use of microRNAs for treatment is complicated by the fact that these molecules decompose rapidly in the blood. Scientists have proposed using liposomal nanoparticles targeted at cancer cells to deliver microRNA to the tumor in a stable form. However, there were problems here: once in the cell, nanoparticles can end up in endosomes, compartments from the lipid membrane. Then the microRNAs cannot reach their target and eventually disintegrate.

To overcome this effect, scientists have developed nanoparticles, which include an additional agent – ammonium bicarbonate (baking powder used in baking confectionery and bakery products – VM). Under the action of a near-infrared laser beam, the substance decomposes into carbon dioxide and ammonia, and the nanoparticle increases in volume three times. In this case, liposomes are torn, and microRNAs are released. 

Diagram from an article in Advanced Materials – VM

The system was tested on prostate cancer cell culture and human prostate cancer model in mice. The use of nanobombs has led to a significant reduction in the size of tumors.

Another recent breakthrough related to the treatment of tumors is overcoming the hemato–encephalic barrier, a physiological property of the brain that did not allow drugs to be delivered to cancer cells. Scientists were able to work around this problem by using ultrasound and micro-bubbles of gas.

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