Fig. 16. Sensing and imaging applications of plasmonic traps.

a Suppression of DNA hairpin unzipping by the tumour suppressor protein p53. Left: Wild-type p53 suppresses unzipping of the DNA hairpin for a delay of ~10 s. Right: Energy reaction diagram showing an increased energy barrier ∆U equivalent to the binding energy ∆G of p53 and DNA. b SERS detection of the DNA sequence. Left: Typical conformation of dsDNA trapped by plasmonic hotspots; the base pairs are numbered in ascending order from the trailing to the leading end of the molecule. Right: SERS signals from a poly(AT) block in the poly(CG) background. c SERS imaging of plasmonically trapped molecules in a three-dimensional plasmonic cavity. a Adapted with permission from ref. ²³³, copyright 2014 Optical Society of America. b Adapted with permission from ref. ²⁴⁹, Copyright 2015, American Chemical Society. c Adapted with permission from ref. ³¹⁰, Copyright 2015, American Chemical Society