ABSTRACT
We have recorded nanoscale topography and infrared chemical fingerprints of attomole layered lipids consisting of dimyristoylpho-sphatidylcholine on silicon and mica. Lipids deposited on mica built stacks consisting of up to 25 bilayers, each approximately 5 nm thick, spanning a range from 5-125 nm in height. Contrast evaluation as a function of layer thickness provides the near-field depth resolution.
Subject(s)
Lipid Bilayers/chemistry , Microscopy/methods , Nanotechnology/methods , Optics and Photonics , Spectroscopy, Near-Infrared/methods , Aluminum Silicates/chemistry , Cell Membrane/metabolism , Dimyristoylphosphatidylcholine/chemistry , Equipment Design , Microscopy, Atomic Force/methods , Nanoparticles/chemistry , Nanostructures/chemistry , Silicon/chemistryABSTRACT
We have realized a scanning near-field infrared microscope in the 3-4 microm wavelength range. As a light source, a tunable high power continuous wave infrared optical parametric oscillator with an output power of up to 2.9 W in the 3-4 microm range has been set up. Using scanning near field infrared microscopy (SNIM) imaging we have been able to obtain a lateral resolution of < or =30 nm at a wavelength of 3.2 microm, which is far below the far-field resolution limit of lambda/2. Using this "chemical nanoscope" we could image a sub-surface structure of implanted gallium ions in a topographically flat silicon wafer giving evidence for a near-field contrast. The observed contrast is explained in terms of the effective infrared reflection as a function of the sub-surface gallium doping concentration. The future use of the setup for nm imaging in the chemically important OH, N-H and C-H stretching vibration is discussed.
Subject(s)
Gallium/chemistry , Nanostructures/chemistry , Nanostructures/ultrastructure , Silicon/chemistry , Spectroscopy, Near-Infrared/instrumentation , Spectroscopy, Near-Infrared/methods , Chemical Phenomena , Chemistry, Physical , Computer Simulation , Microscopy, Atomic Force , Microscopy, Confocal/instrumentation , Microscopy, Confocal/methods , Particle Size , Surface PropertiesABSTRACT
We have set up a near-infrared microscope using a tuneable diode laser in the range from 1530 to 1570 nm. This spectral range is close to the peak of the water overtone absorption. We used this new microscope to study liver cells, hepatocytes, showing that quantitative information of the intracellular water concentration in living cells can be extracted.
