Russian scientists developed a general technique for producing micro-containers, which will be perfect for creating DNA-vaccines, able to provide stable and powerful immunity for those, who take them. These containers have multilayer biodegradable shell, which can host proteins, DNA and other molecules.

The world knows little about such micro-containers for DNA delivery. Shells of foreign containers consist of polylactic acid, and such capsules are the basis for vaccines against hepatitis and HIV. Russian biochemists suggest the simplest ever technique for producing such containers – no complex equipment, only bench centrifuge is required.

Researchers place protein, DNA or any other substance they want to be delivered inside an organism, inside a porous microsphere, made of calcium carbonate (CaCO₃). Then they cover the microsphere with a semipermeable membrane, containing several layers of natural polymers – polysaccharides. The sphere can also be covered with polypeptides or composite shell. When microspheres, covered with polymers, get into an acidified solution, calcium carbonate dissolves and leaves the sphere through the polymer membrane, leaving protein or DNA ready for transportation.

Tiny capsules for DNA-vaccines have about 1-2 microns in diameter, and they can become even tinier, if we take smaller carbonate spheres. Such capsules can be injected subcutaneously or even directly in blood. Small size provides free flowing of these capsules along blood vessels, since they are smaller than erythrocytes and change shape when traveling through narrow capillaries. Cells “absorb”capsules, and their shell dissolves, releasing active “filling”.

 

 

The technique allows delivery of treating agents to cells that need therapy, as well as prolongation and regulation of action time. When we insert an enzyme, splitting container membrane, into microcapsule together with DNA or other treating molecule, we can regulate the process of treating agent release – the lesser amount of enzyme we put inside the capsule, the slower its membrane deteriorates. Russian biochemists have successfully tested their capsules on mice and cell lines. Common vaccine contains proteins of viruses or bacteria, and DNA-vaccine – genes, which encode said proteins. Antigen proteins of a common vaccine usually decompose rapidly, since they are alien for organisms, which are subject to vaccination. The same happens with non-capsulated DNA – appropriate enzymes break it. DNA in microcapsules helps an organism produce its own antigen, forming immunity. This process is slow, since capsules dissolve for at least one month and maintain antigen concentration, necessary for stable immunity.

Scientists claim that injections are not the only way to deliver DNA-vaccines to an organism. Microcapsules can get inside you by means of sprays, which can be dispersed on oral or nasal mucous coat and for immunity against some certain disease. Researchers consider DNA-vaccines to be the future of medicine, and it becomes closer with new technique for their delivery into an organism. However, delivering therapy to ailing organ is not the only application of developed technique.

Source: Science & Technology

Kizilova Anna