Polarization-controlled photoswitching resolves dipole directions with subwavelength resolution.
We present that modulation of fluorescence emission by linearly polarized excitation light can allow us to resolve spatially two fluorescent molecules within a diffraction limit and to determine simultaneously their precise dipole directions. Using polarization-dependent photoswitching, we imaged the 2D geometry of the DNA Holliday junction in a 10-nm length scale by measuring both the distance and the in-plane dipole angle between Cy3 emitters stacked onto the ends of two adjacent branches of the Holliday junction. The proposed polarization-modulated imaging technique provides a simple and nonstochastic imaging process to visualize the nanostructure, including directional information, of biomolecules beyond the diffraction limit.
Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang 790-784, Korea.
Seongsil
S
Lee
Jungsic
J
Oh
Dohyeon
D
Kim
Samuel
S
Kim
Jong-Bong
JB
Lee
Hong Gil
HG
Nam
D002232:Carbocyanines / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D005456:Fluorescent Dyes / Q000737:chemistry*; D045565:Holliday Junction Resolvases / Q000737:chemistry / Q000235:genetics; D008956:Models, Chemical; D055668:Photochemical Processes
D002232:Carbocyanines; D005456:Fluorescent Dyes; C089187:cyanine dye 3; D004247:DNA; D045565:Holliday Junction Resolvases