Nanomedicine ranges from the medical applications of nanomaterials (materials whose structure is on the scale of billionths of a meter), to nanoelectronic biosensors, and even possible future applications of molecular nanotechnology. Nanomaterials can be useful for both in vivo and in vitro biomedical research and applications. Thus far, the integration of nanomaterials with biology has led to the development of diagnostic devices, contrast agents, analytical tools, physical therapy applications, and drug delivery vehicles. Current problems for nanomedicine involve understanding the issues related to toxicity and environmental impact of nanoscale materials.