BRAZILIAN and European researchers have demonstrated exactly how a nanotechnology-based compound delivers an oral vaccine against hepatitis B to the immune system. When particles containing silica and an antigen combine, even though they are different sizes, they reach the intestine without being destroyed by the acidity of the digestive system. A compound of nanostructured SBA-15 silica and HBsAg, the hepatitis B surface antigen, was submitted to different types of X-ray imaging in European laboratories. The nanostructured silica was developed by researchers at the University of São Paulo’s Physics Institute (IF-USP) in Brazil. The antigen was created by the Butantan Institute, which is also in São Paulo.