2. Use of gold nanoparticles: a turning point in diagnostic testing

In vitro diagnostic tests are analytical procedures used to detect the presence of a specific substance in a biological sample (blood, urine, tissue, etc.). The general principle behind these tests is based on the selective interaction between a bioreceptor and the target of interest (recognition stage). This interaction induces a measurable change in a signal, which constitutes the test output (transduction step): this can be an optical change (color, fluorescence, plasmonic or Raman signal), an electrochemical signal (current, potential), or a change in mass detected by a microbalance. Measuring this response makes it possible to determine the presence or concentration of the target analyte, thus providing rapid and reliable diagnostic information.

In vitro diagnostic tests can therefore be used to detect diseases and infections from biological samples without...