学术文献库

The use of drugs or radiation to attack cancerous cells often leaves the treatment material within the body where it could affect healthy cells or damages healthy tissue; as is the case with traditional invasive surgery. An alternative approach is the creation of a nano machine that is directed to its target (the cancerous tissue), then activated to engage cancerous cells and "surgically" induce controlled apoptosis. A magneto-mechanical device composed of nanomagnets that potentially meets this objective is thus predicated. The magnetic particles must be bio-functionalised for "in-body" use where their uniqueness allows precise tracking and manipulation. In order to bio-functionalize magnetic particles they have to be embedded in a biocompatible coating or shell. Even enclosed within a biological entity the application of magnetic field gradients result in significant forces acting upon the magnetic particles. As such, single domain, ferromagnetic particles can be used inside the body for a number of applications. The lack of naturally occurring ferromagnetic particles inside the human body allows the bio-functionalized particles to be detectable, without the interference of noise from the host environment. Therefore, it is of paramount importance, for medical applications, to understand exactly how the magnetic particles will respond to a magnetic field gradient. Accordingly, the magnetic response of a system of four interacting magnetic particles is examined and it is shown that such a system can be optimised for targeting cancer cells and performing nano-surgical operations. The range of magnetic field required for such nano-medical applications is specified and the connection of these applications to different phase transitions arising in the magnetic field is described.