Nanoarchitecture's Influence on Surface-Enhanced Spectroscopy: The Use of Surface-Enhanced Raman Scattering Substrates

The rapid and reliable detection of a diverse set of biomolecules, such as metabolites, pharmaceuticals, nucleic acids, amino acids, proteins, and peptides, requires analytical techniques capable of label-free chemical identification. Inelastic light scattered by a molecule, a quantized vibrational signature, is the physical phenomenon behind Raman spectroscopy [1]. Despite the rich information offered by regular Raman spectroscopy, it has not been the primary choice as a handy analytical tool comparable to Fourier-transform infrared and ultraviolet-visible spectroscopy due to its inherently small scattering cross section. The signal is weak for most molecules except in some special cases of resonating molecular structures. For example, the benzene molecule, which is relatively strong for Raman scattering, exhibits a scattering cross section of 2.6 × 10
^-29
cm
²
·molecule
^-1
·sr
^-1
. This value is 12-14 orders of magnitude lower than a typical fluorescence cross section [2].