Plasmonics and templated systems for bioapplications

Abstract

The science of surface plasmons in noble metal nanoparticles and in thin metal film–glass interfaces is driving most innovations in biochemical and biomedical applications. The sensitivity of these charge density oscillations toward changes in the geometry and the surrounding medium is more than capable in detecting antibody–antigen and molecular interactions, diagnosing an array of diseases, and delivering drugs in the form of an absorption peak in the visible to the near-infrared region. Modifications on the physical parameters and functionalities on the surface can be used to control the position of the maximum localized surface plasmon resonance absorbance peak or the minimum bulk SPR reflectivity dip. Several lithographic techniques such as colloidal templating can now produce binary and tertiary patterns with more controlled SPR peaks. On the other hand, the surfaces of plasmonic materials should also be properly functionalized in order to selectively recognize specific analytes. Hence, the flexible low-cost synthesis of artificial antibodies complements the surface plasmon properties of metallic nanomaterials. Continuous progress in these fields should make low-cost and responsive biosensors available for point-of-care applications and personal diagnostics.