Synthetic latex consist of polymer particles dispered in an aqueous phase. The size of the polymer particles ranges from several nanometers to a few micrometers. Nanosized latex have a lot of interesting properties in biology. Nevertheless, it is not always easy to prepare them and we have developed a new original method of preparation of latex by vinyl polymerisation of various functionalized norbornenes in water emulsions. Their biological properties concern formulations of new vectors for DNA and new biosensors.