Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Imaging biological molecules with single molecule sensitivity using near-field scanning optical microscopy

Conference ·
OSTI ID:151800
We have developed a near-field scanning optical microscope with the sensitivity to detect single fluorescent molecules. Our microscope is based on scanning a sample under a tapered and metal coated fiber optic probe and has an illumination-aperture diameter as small as 100 nm. The microscope simultaneously acquires a shear force image with a height noise of {approximately} 1 nm. We have used this system to demonstrate the detection of single molecules of Rhodamine-6G on silica. In this paper, we explore the use of NSOM for investigations of biological molecules. We have prepared and imaged double-stranded DNA intercalated with thiazole orange homodimer (TOTO); single chromosomes stained with propidium iodide; and {beta}-phycoerythrin proteins on dry, borosilicate-glass surfaces. At very dilute coverages, isolated fluorescent spots are observed for the un-intercalated TOTO dye and for {beta}-phycoerythrin. These fluorescent spots exhibit-emission intensity fluctuations and abrupt bleaching transitions, similar to the intensity behavior observed previously for single Rhodamine 6G molecules on silica.
Research Organization:
Los Alamos National Lab., NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
151800
Report Number(s):
LA-UR--95-3844; CONF-9510259--2; ON: DE96003142
Country of Publication:
United States
Language:
English

Similar Records

Alterations of single molecule fluorescence lifetimes in near-field optical microscopy
Journal Article · Fri Jul 15 00:00:00 EDT 1994 · Science (Washington, D.C.); (United States) · OSTI ID:6768949

Room temperature single molecule microscopes
Conference · Tue Dec 30 23:00:00 EST 1997 · OSTI ID:560335

Fluorescence detection of single molecules using pulsed near-field optical excitation and time correlated photon counting
Conference · Mon Feb 28 23:00:00 EST 1994 · OSTI ID:10129372