The potential medical applications of nanotechnology are by the use of human-engineered devices. These can interact with biological processes in sophisticated ways by the creation of a "smart drug".

Smart drug is a nano-scale device designed to perform a particular medical task such as destroying cancer cells, cleaning out clogged arteries or to construct needed proteins or mimicking anti-bodies.

Researchers have discovered the possible pathway as to how anti-tumor drugs kill cancer cells by tiny drug-delivery particles for use in "nanomedicine."It is generally assumed that polymeric micelles, upon administration into the blood stream, carry drug molecules until they are taken up into cells followed by intracellular release. Result show that the hydrophobic probes in the core are released from micelles in the extracellular space. During administration of polymeric micelles to tumor cells core-loaded probes were found to release to the cell membrane before internalization. Results suggest a membrane-mediated pathway for cellular uptake of hydrophobic molecules preloaded in polymeric micelles and the plasma membrane provides a temporal residence for micelle-released hydrophobic molecules before their delivery to target. Intracellular destinations.Blood-stable micelles deliver hydrophobic drugs to the target site via prolonged circulation and extravasation from the vascular system.

The synthetic "polymer micelles" are drug-delivery spheres 60-100 nanometers in diameter, or roughly 100 times smaller than a red blood cell. The spheres harbor drugs in their inner core and contain an outer shell made of a material called polyethylene glycol.Purdue researchers showed for the first time how this shell of polyethylene glycol latches onto the membranes of cancer cells, allowing fluorescent probes mimicking cancer drugs to enter the cancer cells.Drug enter tumor cells and the micelles break down in the blood before they have a chance to deliver the drug to cancer cells. Experiments showed that "core-loaded" with the drug entered cancer cells within 15 minutes, suggesting a new drug-delivery pathway to kill tumor cells.

Unlike water, blood has many components like surfactants and lipids and proteins that interact with the whole micelle structure. As a result, the micelles are unstable in blood and the drug is released too soon. The micelles remain intact in red blood cells and components of blood plasma except for a class of plasma proteins called alpha and beta globulins, which causes the drug to be released (venere@purdue.edu). The overall drug consumption and side-effects can be lowered significantly by depositing the active agent in the morbid region only and in no higher dose than needed. This highly selective approach reduces costs and human suffering. An example can be found in dendrimers and nanoporous materials. They could hold small drug molecules transporting them to the desired location.