Chemical imaging of microstructured self-assembled monolayers with nanometer resolution

We report on the infrared spectroscopic characterization of microstructured self-assembled monolayers by scanning near-field infrared microscopy. Using a CO laser as the radiation source in the characteristic amide band (at 1711 cm-1 (λ = 5.85 μm)), we were able to image self-assembled monolayers of thiols. The measurements were carried out on well-defined microcontact printed line patterns of monomolecular films of 1-octadecanethiolate and biotinylated alkylthiolate (BAT). The lateral resolution was ∼90 × 90 nm2, which is well below the Abbe limit. The detection limit was 5 × 10-20 mol corresponding to 27 attogram or 30 000 molecules of BAT. This demonstrates the high sensitivity of our setup, which allows recording IR spectra of a single monolayer.

[1]  Gilbert C. Walker,et al.  Monolayer-Sensitive Infrared Imaging of DNA Stripes Using Apertureless Near-Field Microscopy , 2002 .

[2]  A. Barth,et al.  What vibrations tell about proteins , 2002, Quarterly Reviews of Biophysics.

[3]  George M. Whitesides,et al.  Features of gold having micrometer to centimeter dimensions can be formed through a combination of stamping with an elastomeric stamp and an alkanethiol ‘‘ink’’ followed by chemical etching , 1993 .

[4]  Wolfgang Knoll,et al.  MOLECULAR RECOGNITION AT SELF-ASSEMBLED MONOLAYERS - THE CONSTRUCTION OF MULTICOMPONENT MULTILAYERS , 1993 .

[5]  Gerhard Schwaab,et al.  Setup of a scanning near field infrared microscope (SNIM): imaging of sub-surface nano-structures in gallium-doped silicon. , 2006, Physical chemistry chemical physics : PCCP.

[6]  Thomas Taubner,et al.  Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution. , 2006, Nano letters.

[7]  M. Trenary,et al.  Reflection absorption infrared spectroscopy and the structure of molecular adsorbates on metal surfaces. , 2000, Annual review of physical chemistry.

[8]  J. Goudonnet,et al.  Infrared near-field study of a localised absorption in a thin film , 2001 .

[9]  Dong Ha Kim,et al.  Apertureless near-field vibrational imaging of block-copolymer nanostructures with ultrahigh spatial resolution. , 2005, Chemphyschem : a European journal of chemical physics and physical chemistry.

[10]  W. Knoll,et al.  Oligonucleotide hybridization studied by a surface plasmon diffraction sensor (SPDS). , 2004, Nucleic acids research.

[11]  F. Keilmann,et al.  Near-field probing of vibrational absorption for chemical microscopy , 1999, Nature.

[12]  Thalappil Pradeep,et al.  Current understanding of the structure, phase transitions and dynamics of self-assembled monolayers on two- and three-dimensional surfaces , 2003 .

[13]  John C. Keske,et al.  Decoding the dynamical information embedded in highly mixed quantum states. , 2000, Annual review of physical chemistry.

[14]  David A. Russell,et al.  Self-assembled monolayers: a versatile tool for the formulation of bio-surfaces , 2000 .

[15]  C. Grunwald,et al.  Fabrication of 2D-protein arrays using biotinylated thiols: results from fluorescence microscopy and atomic force microscopy , 2004 .

[16]  M. Isaacson,et al.  Development of a 500 Å spatial resolution light microscope: I. light is efficiently transmitted through λ/16 diameter apertures , 1984 .

[17]  Near-field infrared imaging of molecular changes in cholesteryl oleate by free electron laser infrared ablation , 2004 .

[18]  F. Keilmann,et al.  Pure optical contrast in scattering‐type scanning near‐field microscopy , 2001, Journal of microscopy.

[19]  C. Blomfield.  Spatially resolved X-ray photoelectron spectroscopy , 2005 .

[20]  M. Havenith,et al.  High-resolution CO-laser sideband spectrometer for molecular-beam optothermal spectroscopy in the 5–6.6 μm wavelength region , 1999 .

[21]  W. Urban.  Physics and spectroscopic applications of carbon monoxide lasers, a review , 1995 .

[22]  Akira Kinbara,et al.  Optical effect of the substrate on the anomalous absorption of aggregated silver films , 1974 .

[23]  Gilbert C. Walker,et al.  Apertureless Scanning Near-Field Infrared Microscopy of a Rough Polymeric Surface , 2001 .

[24]  F. Keilmann,et al.  Infrared conductivity mapping for nanoelectronics , 2000 .

[25]  N. K. Chaki,et al.  Self-assembled monolayers as a tunable platform for biosensor applications. , 2002, Biosensors & bioelectronics.

[26]  F. Keilmann,et al.  Scanning microscopy by mid-infrared near-field scattering , 1998 .

[27]  E. Synge.  XXXVIII. A suggested method for extending microscopic resolution into the ultra-microscopic region , 1928 .

[28]  F. Keilmann,et al.  Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy , 2004 .

[29]  Alain Croisy,et al.  Progress in analytical imaging of the cell by dynamic secondary ion mass spectrometry (SIMS microscopy). , 2005, Biochimica et biophysica acta.

[30]  W. Hinsberg,et al.  Water Vapor Uptake in Photolithographic Polymers Observed by Infrared Near-Field Scanning Optical Microscopy in a Controlled Environment , 2003 .

[31]  A. Boccara,et al.  Infrared near-field imaging of implanted semiconductors: Evidence of a pure dielectric contrast , 1997 .

[32]  Jerry Workman.  Review of Process and Non-invasive Near-Infrared and Infrared Spectroscopy: 1993-1999 , 1999 .

[33]  George M. Whitesides,et al.  The interaction of proteins and cells with self-assembled monolayers of alkanethiolates on gold and silver , 1999 .

[34]  D. Piston,et al.  Chemically resolved imaging of biological cells and thin films by infrared scanning near-field optical microscopy. , 2003, Biophysical journal.

[35]  M. Diem,et al.  A decade of vibrational micro-spectroscopy of human cells and tissue (1994-2004). , 2004, The Analyst.