Figure 15.

Detection of miRNA-21 based on Au@PDA microtube waveguide. (a) Schematic diagram. (b) Microscopy of PDA microtube and Au@PDA microtube waveguide sensor with increasing miR-21. (c) PL changes for tip emission of PDA microtube upon increasing miRNA-21. (d) Plot of PL changes of the waveguided tip emission at 640 nm upon addition of miR-21. I₀ and I represent PL intensity before and after reaction with miRNA-21, respectively (the whole Figure 15 was reprinted with permission from Zhu et al. [64]).