Nanomedicine-biological warfare at the cellular level

Nanomedicine may be defined as the application of nanotechnology to detect and to treat disease. The ability to shape and control matter at the nanoscale presents the opportunity to prevent or to cure disease at its source-at the level of molecular interactions. By delivering nanoparticles into cells, the molecular pathways and interactions that control cell function can be directly influenced, either to restore proper balance or to kill rogue cells, for example, cancer cells. However, our body's natural defences are constantly monitoring for foreign invaders, and our immune system readily attacks nanoparticles. Thus, in pursuing nanotherapeutic treatments, we engage in biological warfare, and the challenge to the nanotechnologist is not only to engineer particles with a specific set of physiochemical characteristics but to also avoid the white blood cell, sentinels which will destroy or remove the particles. In this chapter, I review the basic principles which control nanoparticle dynamics in solution, that is, under conditions appropriate to the body, and highlight the key elements of nanoparticle-cell interactions through examination of a naturally evolved nanoparticle which is highly efficient in controlling cells-the virion, or virus particle.