g., for the detection of nuclear, chemical, or biological threats);surveillance [14] of open public places, such as parks, squares, streets, suburbs, or closed ones such as malls, schools, city halls, hospitals;real-time support for firemen and rescue squads [15] to locate themselves, and to navigate inside a building in case of emergency; moreover, this might include communicating the fireman position to external supervision centers, in order to improve coordinated search strategies;precision agriculture [16�C18]: recently, the use of sensor networking technologies in far
Since the first utilization of gold nanoparticles in an immunoassay for human chorionic gonadotrophin in the form of a pregnancy test in 1980 [1], nanomaterials are an inherent part of immunological methods.

Currently, nanomaterials include quantum dots and metallic nanoparticles as improved labels as well as optical reporters. Nanowires as label-free biosensors and superparamagnetic nanoparticles are used for magnetic separation of biomolecules. The latter were applied GSK-3 in heterogeneous (e.g. enzyme linked immunosorbent assays �C ELISAs) [2,3] or homogeneous immunoassays, where signals are detected magnetically by superconducting quantum interference devices (SQUIDs) [4,5], fluxgate sensors [6] or susceptibility measurements [7].Biosensor systems based on biomolecular recognition are the most widely used analytical technology in biodiagnostics, including the determination of antigens, hormones and drugs by means of antibody application [8].

Antibodies offer quality characteristics, which predestine them for the application in immunoassays: the selectivity to bind to an extremely high variety of molecules, cells or viruses, the high binding specificity and the high bond strength between antibody and antigen. Since nanotechnology found its way into bioanalytical methods, analyses on a minimized scale are possible, which allows for simultaneous detection of numerous analytes and reduced sample volumes.This contribution concentrates on a homogeneous immunoassay of insulin like growth factor 1 (IGF-1) and its polyclonal antibody anti-IGF-1 with magnetic nanoparticles (MNPs) as signal generators. IGF-1 (7.7 kDa) is the most important peripheral mediator of growth hormone action [9] and it is mainly synthesized in the liver in response to growth hormone stimulation [10]. It has been found that the risk of cancer, diabetes and acromegaly is higher among people with raised blood levels of IGF-1 [11,12].