Nanotechnology is tested as a possible means of delivering vaccines. The team of researchers has shown how an oral vehicle, SBA-15, one such nanotechnological compound, can deliver an oral vaccine against hepatitis B to the immune system.
Researchers from Brazil and Europe have shown that the delivery system of nanotechnologies, which is the particles containing silica and HBsAg, the surface antigen of hepatitis B, enters the intestine without destroying the acidity of the stomach. The study could pave the way for the development of new vaccines and delivery methods that are safe and non-invasive.
Nanotechnology of Biomedical Illustrations Illustrations. Image: HaHanna / Shutterstock
Oral delivery of antigens for vaccination is an attractive idea for scientists, mainly because they are non-invasive in nature, safe and painless in children. In addition, oral delivery is cost effective, which makes it a good offer for immunization.
However, the development of a technology that allows the effective use of oral vaccines remains a very difficult task, as there are many problems that need to be addressed. Firstly, the vaccine should be delivered to the intestine without changes or damage to acids in the stomach. The main purpose is to ensure that the delivery system can withstand rigid conditions in the gastrointestinal tract.
Hepatitis B is a vaccine that helps protect the body from hepatitis B, which is caused by the virus. This can lead to inflammation of the liver, and in the long run may cause scarring of the organ, liver failure and cancer. The virus can be acquired through the influence of blood, semen and other body fluids. Mother can also transmit the virus to her children through pregnancy.
The hepatitis B vaccine is usually given through the intradermal after-birth, at least one month after the initial shot, and at least 2 months after the second shot. Booster doses are given every ninety years.
Nanotechnology delivery system
The research published in the journal Scientific reports and with the support of the São Paulo Foundation for Research (FAPESP) and European research founders, a viable approach, an oral hepatitis B drug in nanobructured SBA-15 silicagel, can be an effective way of delivering an oral vaccine.
Scientists at the Institute for the Physics of São Paulo (IF-USP) in Brazil developed nanostructured silica and the Butantan Institute developed an oral antigen. Silabagel SBA-15 and antigen were submitted to various types of X-ray imaging in European laboratories.
The researchers have researched how 22 nm antigen size is found in nanoscale silica with a diameter of about 10 nanometers and a cell type structure. One nanometer, shortened by 1 nm, is a billionth of a meter.
Studies have shown measurements of both nanotubes and antigens using low angle x-ray scattering (SAXS), translucent electron microscopy and dynamic light scattering (DLS).
"Despite the difference in size, tests [in animals] received an excellent immune response to an oral vaccine – as good as another form of presentation or better, "said Marcia Fanning, co-author of the study and professor of IF-USP.
3D images collected using various methods have shown that, despite the fact that the antigen does not enter the nanotubes, it stays in the macropores of 50 nm between the nanotubes, which means that the antigen is protected from the acids of the stomach.
Therefore, researchers now know the ideal proportion of both compounds, so the antigen is not agglomerated, preventing it from dispersing the active antigen in the intestine.
In conclusion, the results obtained with the encapsulated HBsAg antigen are the first to demonstrate how SBA-15 protects the antigen for the oral administration of the hepatitis B vaccine. The encapsulated vaccines combine the benefits of immunization with ease of oral administration and accompanying induction of the immune response, "- argue. researchers in the study.
Scientists plan to test polymers that can cover the entire structure. Thus, the resistance of the antigen to the acidity of the human stomach can be enhanced and increased.
Meanwhile, some scientists led by Bordalo, Sant'Anna and Fantini are developing new antigens that are added to the association. Consequently, in addition to hepatitis B, they plan to add more such antigens as diphtheria and tetanus.
Moreover, they plan to formulate a polyvalent that can also help to immunize people against poliomyelitis, pertussis and HBV, a vaccine that protects people from pneumonia and meningitis.
Martin K. Rasmussen, Nikolai Kardzilov, Kristiano L.P. Oliveira, Benjamin Watts, Julie Villanova, Vivian Fonggaro Botosso, Osvaldo A. Sant'Anna, Marcia F. https://www.nature.com/articles/s41598-019-42645-5