Selective fluorescence and fluorescence-free detection of single biomolecules on nanobiochips

This topical review provides an overview of selective fluorescence and fluorescence-free detection on nanobiochips fabricated by nanopatterning techniques such as nanolithography and the use of artificial nanostructures (arrays of pillars, holes, and wires). The unique properties of nanostructured surfaces have led to applications in biomedical nanoarrays used for either diagnostic or functional assays on chips. Some targets can be optically detected using not only colorimetry, chemiluminescence or the most developed fluorescence mode, but also more recent non-conventional optical methods. Two main approaches have been used: fluorescence (e.g., epifluorescence and total internal reflection) and fluorescence-free (e.g., surface plasmon resonance, optical resonance, dark-field scattering, atom force microscopy, electrochemical method, etc.) detection. The aim of the present paper is to review the most recent progress in nanobiochips in the development of new selective fluorescence and fluorescence-free detection at the single-molecule level.