While DNA is the building block of life, its cousin RNA keeps the show running smoothly, as it carries the information from DNA that allow genes to be expressed. RNA's ability to increase or decrease the expression of genes means it has huge potential to treat diseases at the genetic level, including tumors and chronic wounds.
This process is known as RNA interference, and this medical application is reliant on what's known as oligonucleotides — basically, short strands of RNA molecules that can be delivered to wherever they are needed to affect the expression of genes within the body. But most delivery mechanisms for these RNA strands involve a trip through the bloodstream, and the molecules are often too fragile to survive the trip. As Katherine Bourzac writes in Chemical & Engineering News, a new strategy is to bring the RNA directly to wherever they are needed. In the case of chronic wounds near the flesh that just won't heal, that means a bandage coated with the strands. For tumors inside the body, surgeons could leave a polymer after operating that would gradually dissolve and release the RNA strands. The molecules would then seek out any remaining tumor cells and switch off the genes that promote growth. Here's how it all works:
Small interfering RNAs, or siRNAs, derail expression of specific genes in cells by binding to other RNA molecules that contain the code for those genes. Biologists have developed siRNAs that target disease-related genes. But for these siRNAs to reach the clinic, researchers must find a way to deliver the molecules safely to the right cells. Unfortunately, free oligonucleotides like siRNAs don’t fare well inside the body or cells as enzymes and acids quickly chop them up, says Paula T. Hammond, a chemical engineer at Massachusetts Institute of Technology... Hammond and her colleagues produced an siRNA-containing nanocoating that could be applied to a wide range of medical materials, such as bandages or biodegradable polymers doctors could implant during surgery to prevent an excised tumor from coming back. As the coating slowly dissolves, it releases siRNA molecules tethered to protective nanoparticles.
For more, check out the rest of the story over at Chemical & Engineering News.
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