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. 2009 Oct 1;106(42):17735–17740. doi: 10.1073/pnas.0907367106

Fig. 1.

Fig. 1.

Crown nanoparticle plasmon rulers. (A) Schematic of crown nanoparticle probes, which are composed of a NeutrAvidin-coated gold-core nanoparticle with multiple biotinylated gold satellite nanoparticles. Peptides with the caspase-3 cleavage sequence DEVD crosslink the core and satellite nanoparticles via avidin-biotin interactions. (B) Transmission electron microscopy (TEM) of crown nanoparticles. Approximately 3–6 satellite nanoparticles are linked to the core nanoparticle. (C) A representative scattering image of crown nanoparticles. Intense and bright red-colored spots correspond to a single-crown nanoparticle. (D) Representative scattering spectra of a single-crown nanoparticle (red) and a single gold nanoparticle (black). A single-crown nanoparticle probe exhibited a significant red shift (Δλ = 75 nm) and highly increased scattering intensity (≈44 times) compared with a single gold nanoparticle.