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Lanzarotta A.,Miami University Ohio | Lanzarotta A.,U.S. Food and Drug Administration | Marcott C.,Light Light Solutions LLC | Story G.M.,Procter and Gamble | And 2 more authors.
Applied Spectroscopy | Year: 2012

Several prism-based spectrographs employing a mercury cadmium telluride (MCT) focal plane array detector have been interfaced to an infrared microscope. In the combined system, the area-defining aperture of the microscope also served as the entrance slit to the spectrograph. This investigation considered the fundamental limits of diffraction for both the spectrograph and microscope in order to determine both the spatial and spectral resolution of the system as a whole. Experimental results for spectral resolution, spectral range, and peak-to-peak noise have been presented. Finally, the dynamic capabilities of one spectrograph/microscope combination were investigated. © 2012 Society for Applied Spectroscopy.


Dazzi A.,University Paris - Sud | Prater C.B.,Anasys Instruments Corp. | Hu Q.,Anasys Instruments Corp. | Chase D.B.,University of Delaware | And 2 more authors.
Applied Spectroscopy | Year: 2012

Polymer and life science applications of a technique that combines atomic force microscopy (AFM) and infrared (IR) spectroscopy to obtain nanoscale IR spectra and images are reviewed. The AFM-IR spectra generated from this technique contain the same information with respect to molecular structure as conventional IR spectroscopy measurements, allowing significant leverage of existing expertise in IR spectroscopy. The AFM-IR technique can be used to acquire IR absorption spectra and absorption images with spatial resolution on the 50 to 100 nm scale, versus the scale of many micrometers or more for conventional IR spectroscopy. In the life sciences, experiments have demonstrated the capacity to perform chemical spectroscopy at the sub-cellular level. Specifically, the AFM-IR technique provides a label-free method for mapping IR-absorbing species in biological materials. On the polymer side, AFM-IR was used to map the IR absorption properties of polymer blends, multilayer films, thin films for active devices such as organic photovoltaics, microdomains in a semicrystalline polyhydroxyalkanoate copolymer, as well as model pharmaceutical blend systems. The ability to obtain spatially resolved IR spectra as well as high-resolution chemical images collected at specific IR wavenumbers was demonstrated. Complementary measurements mapping variations in sample stiffness were also obtained by tracking changes in the cantilever contact resonance frequency. Finally, it was shown that by taking advantage of the ability to arbitrarily control the polarization direction of the IR excitation laser, it is possible to obtain important information regarding molecular orientation in electrospun nanofibers. © 2012 Society for Applied Spectroscopy.


Marcott C.,Light Light Solutions LLC | Marcott C.,University of Delaware | Lo M.,Anasys Instruments Corp. | Hu Q.,Anasys Instruments Corp. | And 3 more authors.
Journal of Molecular Structure | Year: 2014

The recent combination of atomic force microscopy and infrared spectroscopy (AFM-IR) has led to the ability to obtain IR spectra with nanoscale spatial resolution, nearly two orders-of-magnitude better than conventional Fourier transform infrared (FT-IR) microspectroscopy. This advanced methodology can lead to significantly sharper spectral features than are typically seen in conventional IR spectra of inhomogeneous materials, where a wider range of molecular environments are coaveraged by the larger sample cross section being probed. In this work, two-dimensional (2D) correlation analysis is used to examine position sensitive spectral variations in datasets of closely spaced AFM-IR spectra. This analysis can reveal new key insights, providing a better understanding of the new spectral information that was previously hidden under broader overlapped spectral features. Two examples of the utility of this new approach are presented. Two-dimensional correlation analysis of a set of AFM-IR spectra were collected at 200-nm increments along a line through a nucleation site generated by remelting a small spot on a thin film of poly(3- hydroxybutyrate-co-3-hydroxyhexanoate). There are two different crystalline carbonyl band components near 1720 cm-1 that sequentially disappear before a band at 1740 cm-1 due to more disordered material appears. In the second example, 2D correlation analysis of a series of AFM-IR spectra spaced every 1 μm of a thin cross section of a bone sample measured outward from an osteon center of bone growth. There are many changes in the amide I and phosphate band contours, suggesting changes in the bone structure are occurring as the bone matures. © 2014 Elsevier Ireland Ltd. All rights reserved.


Marcott C.,Light Light Solutions LLC | Lo M.,Anasys Instruments Corp. | Kjoller K.,Anasys Instruments Corp. | Domanov Y.,L'Oréal | And 2 more authors.
Experimental Dermatology | Year: 2013

An atomic force microscope (AFM) and a tunable infrared (IR) laser source have been combined in a single instrument (AFM-IR) capable of producing ~200-nm spatial resolution IR spectra and absorption images. This new capability enables IR spectroscopic characterization of human stratum corneum at unprecendented levels. Samples of normal and delipidized stratum corneum were embedded, cross-sectioned and mounted on ZnSe prisms. A pulsed tunable IR laser source produces thermomechanical expansion upon absorption, which is detected through excitation of contact resonance modes in the AFM cantilever. In addition to reducing the total lipid content, the delipidization process damages the stratum corneum morphological structure. The delipidized stratum corneum shows substantially less long-chain CH2-stretching IR absorption band intensity than normal skin. AFM-IR images that compare absorbances at 2930/cm (lipid) and 3290/cm (keratin) suggest that regions of higher lipid concentration are located at the perimeter of corneocytes in the normal stratum corneum. © 2013 John Wiley & Sons A/S.


Van Eerdenbrugh B.,Purdue University | Van Eerdenbrugh B.,Catholic University of Leuven | Lo M.,Anasys Instruments Corp. | Kjoller K.,Anasys Instruments Corp. | And 2 more authors.
Molecular Pharmaceutics | Year: 2012

Determining the extent of miscibility of amorphous components is of great importance for certain pharmaceutical systems, in particular for polymer-polymer and polymer-small molecule blends. In this study, the application of standard atomic force microscopy (AFM) measurements combined with nanoscale mid-infrared (mid-IR) spectroscopy was explored to evaluate miscibility in binary polymer blends. The miscibility characteristics of a set of 50/50 (w/w) polymer blends comprising of poly(vinylpyrrolidone) (PVP) with dextran or maltodextrin (DEX) of varying molecular weights (MWs) were investigated. Standard AFM characterization results show good agreement with inferences drawn from differential scanning calorimetry (DSC) analysis in terms of forming either single or two phase systems. AFM analysis also provided insight into the microstructure of the two phase systems and how domain sizes varied as a function of polymer MWs. Nanoscale mid-IR evaluation of the blends, performed by collecting local mid-IR spectra or spectral maps, provided an extra dimension of information about the dependence of polymer MWs on chemical composition of the different phases. AFM, combined with nanoscale mid-infrared analysis, thus appears to be a promising technique for the evaluation of miscibility in certain pharmaceutical blends. © 2012 American Chemical Society.


Marcott C.,Light Light Solutions LLC | Lo M.,Anasys Instruments Corp. | Kjoller K.,Anasys Instruments Corp. | Prater C.,Anasys Instruments Corp. | Noda I.,Procter and Gamble
Applied Spectroscopy | Year: 2011

Atomic force microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument (AFM-IR) capable of producing sub-micrometer spatial resolution IR spectra and absorption images. This new capability enables the spectroscopic characterization of microdomain-forming polymers at levels not previously possible. Films of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) were solution cast on ZnSe prisms, followed by melting and annealing to generate crystalline microdomains of different sizes. A tunable IR laser generating pulses of the order of 10 ns was used for excitation of the sample films. Short duration thermomechanical waves, due to infrared absorption and resulting thermal expansion, were studied by monitoring the resulting excitation of the contact resonance modes of the AFM cantilever. Dramatic differences in the room-temperature IR spectra are observed in the 1200-1300 cm -1 range as a function of position on a spatial scale of less than one micrometer. This spectral region is particularly sensitive to the polymer backbone conformation. Such dramatic spectral differences have also been observed previously in bulk IR measurements, but only by comparing room-temperature spectra with ones collected at higher temperatures. Less dramatic, but significant, AFM-IR spectral differences are observed in the carbonyl stretching region around 1720 cm -1 as a function of location on the sample. Two overlapping, but relatively sharp, carbonyl bands are observed near 1720 cm -1 in more crystalline regions of the polymer, while a broader carbonyl stretching band appears centered at 1740 cm -1 in the more amorphous regions. Using this spectral region, it is possible to monitor the development of polymer crystalline structures at varying distances from a nucleation site, where the site was generated by bringing a heated AFM tip close to a specific location to locally anneal the sample. © 2011 Society for Applied Spectroscopy.


Marcott C.,Light Light Solutions LLC | Lo M.,Light Light Solutions LLC | Kjoller K.,Light Light Solutions LLC | Fiat F.,Light Light Solutions LLC | And 3 more authors.
Applied spectroscopy | Year: 2014

Atomic force microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument (AFM-IR) capable of producing IR spectra and absorption images at a sub-micrometer spatial resolution. This new device enables human hair to be spectroscopically characterized at levels not previously possible. In particular, it was possible to determine the location of structural lipids in the cuticle and cortex of hair. Samples of human hair were embedded, cross-sectioned, and mounted on ZnSe prisms. A tunable IR laser generating pulses of the order of 10 ns was used to excite sample films. Short duration thermomechanical waves, due to infrared absorption and resulting thermal expansion, were studied by monitoring the resulting excitation of the contact resonance modes of the AFM cantilever. Differences are observed in the IR absorbance intensity of long-chain methylene-containing functional groups between the outer cuticle, middle cortex, and inner medulla of the hair. An accumulation of structural lipids is clearly observed at the individual cuticle layer boundaries. This method should prove useful in the future for understanding the penetration mechanism of substances into hair as well as elucidating the chemical nature of alteration or possible damage according to depth and hair morphology.


Eby T.,Kimberly-Clark Corporation | Gundusharma U.,Kimberly-Clark Corporation | Lo M.,Anasys Instruments Corp. | Sahagian K.,Anasys Instruments Corp. | And 2 more authors.
Spectroscopy Europe | Year: 2012

Using a combination of nanoscale infrared spectroscopy (AFM-IR) and nanoscale thermal analysis (nanoTA), the composition of a complex multilayer polymer film was deconstructed. (Table 1). Using an AFM cantilever as an IR absor-bance detector, the topography of the film's cross-section is directly correlated to the corresponding infrared spectra and transition temperatures at high spatial resolution. Chemical information about the small organic inclusions (as small as 1.2 pm) is extracted within Layers 4 and 6. The nanoTA technique determined the transition temperatures of each layer of the cross-section. Not only do the two methods complement and strengthen the validity of the chemical assignments, the chemical and thermal properties can be linked to the spatial and topographic information about the same sample. The results of AFM-IR and nanoTA may be combined with findings from other techniques such as scanning electron microanalysis (SEM) to obtain a full understanding of the material. Copyright © 2010 John Wiley & Sons Ltd and IM Publications LLP.


PubMed | Light Light Solutions LLC
Type: Comparative Study | Journal: Applied spectroscopy | Year: 2014

Atomic force microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument (AFM-IR) capable of producing IR spectra and absorption images at a sub-micrometer spatial resolution. This new device enables human hair to be spectroscopically characterized at levels not previously possible. In particular, it was possible to determine the location of structural lipids in the cuticle and cortex of hair. Samples of human hair were embedded, cross-sectioned, and mounted on ZnSe prisms. A tunable IR laser generating pulses of the order of 10 ns was used to excite sample films. Short duration thermomechanical waves, due to infrared absorption and resulting thermal expansion, were studied by monitoring the resulting excitation of the contact resonance modes of the AFM cantilever. Differences are observed in the IR absorbance intensity of long-chain methylene-containing functional groups between the outer cuticle, middle cortex, and inner medulla of the hair. An accumulation of structural lipids is clearly observed at the individual cuticle layer boundaries. This method should prove useful in the future for understanding the penetration mechanism of substances into hair as well as elucidating the chemical nature of alteration or possible damage according to depth and hair morphology.


Atomic force microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument (AFM-IR) capable of producing sub-micrometer spatial resolution IR spectra and absorption images. This new capability enables the spectroscopic characterization of microdomain-forming polymers at levels not previously possible. Films of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) were solution cast on ZnSe prisms, followed by melting and annealing to generate crystalline microdomains of different sizes. A tunable IR laser generating pulses of the order of 10 ns was used for excitation of the sample films. Short duration thermomechanical waves, due to infrared absorption and resulting thermal expansion, were studied by monitoring the resulting excitation of the contact resonance modes of the AFM cantilever. Dramatic differences in the room-temperature IR spectra are observed in the 1200-1300 cm(-1) range as a function of position on a spatial scale of less than one micrometer. This spectral region is particularly sensitive to the polymer backbone conformation. Such dramatic spectral differences have also been observed previously in bulk IR measurements, but only by comparing room-temperature spectra with ones collected at higher temperatures. Less dramatic, but significant, AFM-IR spectral differences are observed in the carbonyl stretching region around 1720 cm(-1) as a function of location on the sample. Two overlapping, but relatively sharp, carbonyl bands are observed near 1720 cm(-1) in more crystalline regions of the polymer, while a broader carbonyl stretching band appears centered at 1740 cm(-1) in the more amorphous regions. Using this spectral region, it is possible to monitor the development of polymer crystalline structures at varying distances from a nucleation site, where the site was generated by bringing a heated AFM tip close to a specific location to locally anneal the sample.

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