Graphene-Based Platform for Infrared Near-Field Nanospectroscopy of Water and Biological Materials in an Aqueous Environment

AbstractBiological molecules such as oligonucleotides, proteins, or peptides can be used for the synthesis, recognition, and assembly of materials with nanoscale dimensions. Of particular interest are the fields of near-field optics and plasmonics. Many potential optical applications depend on the ability to control the relative positioning of organic dyes, plasmon-resonant metal nanoparticles, and semiconductor quantum dots with nanoscale precision. In this article, we describe some recent achievements in biological assembly and nanophotonics, and discuss potential uses of biological materials for assembling optically functional nanostructures. We emphasize the use of biological materials to build well-defined nanostructures for near-field plasmon-enhanced fluorescence.

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Development of near-field optic/atomic-force microscope for biological materials in aqueous solutions

Ultramicroscopy ◽

10.1016/0304-3991(95)00113-1 ◽

1995 ◽

Vol 61 (1-4) ◽

pp. 265-269 ◽

Cited By ~ 22

Author(s):

Hiroshi Muramatsu ◽

Norio Chiba ◽

Takeshi Umemoto ◽

Katsunori Homma ◽

Kunio Nakajima ◽

...

Keyword(s):

Aqueous Solutions ◽

Atomic Force Microscope ◽

Near Field ◽

Biological Materials ◽

Atomic Force

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Near-field optical probes provide subdiffraction-limited excitation areas for fluorescence correlation spectroscopy on membranes

Pure and Applied Chemistry ◽

10.1351/pac-con-08-10-10 ◽

2009 ◽

Vol 81 (9) ◽

pp. 1645-1653 ◽

Cited By ~ 4

Author(s):

Dusan Vobornik ◽

Daniel S. Banks ◽

Zhengfang Lu ◽

Cécile Fradin ◽

Rod Taylor ◽

...

Keyword(s):

Fluorescence Correlation Spectroscopy ◽

Near Field ◽

Correlation Spectroscopy ◽

Probe Design ◽

Aqueous Environment ◽

Optical Probes ◽

Aperture Diameter ◽

Fluorescence Correlation ◽

Observation Area ◽

Order Of Magnitude

Near-field optical probes have been used to produce a subdiffraction-limited observation area for fluorescence correlation spectroscopy (FCS) experiments on supported membranes. The design of a bent, etched fiber probe that is compatible with biological imaging in an aqueous environment is described. This probe design is used for proof of principle experiments to measure lipid diffusion in a fluid-supported bilayer. A reduction in excitation area of approximately one order of magnitude (relative to a confocal FCS experiment) is obtained with a probe aperture diameter of 140 nm. We also demonstrate a simple approach for modeling the autocorrelation decay due to diffusion within the excitation profile at the near-field scanning optical microscopy (NSOM) probe aperture. The use of probes with smaller apertures is expected to provide an additional order of magnitude reduction in the observation area, thus enabling the study of cellular membranes with higher concentrations of fluorophores than is currently possible with diffraction-limited techniques.

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New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006427x ◽

1971 ◽

Vol 29 ◽

pp. 44-45

Author(s):

R. C. Moretz ◽

G. G. Hausner ◽

D. F. Parsons

Keyword(s):

Electron Microscopy ◽

Water Vapor ◽

Electron Diffraction ◽

Water Vapor Pressure ◽

Biological Materials ◽

Thin Membrane ◽

Reliable System ◽

System A ◽

Water Films ◽

Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079176 ◽

1977 ◽

Vol 35 ◽

pp. 330-333

Author(s):

T. Gulik-Krzywicki ◽

M.J. Costello

Keyword(s):

Biological Materials ◽

Molecular Organization ◽

X Ray Diffraction ◽

Glass Capillary ◽

X Ray ◽

Rate Dependent ◽

Before And After ◽

Freeze Etching ◽

Diffraction Patterns ◽

Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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