Infrared Imaging and Spectroscopy Beyond the Diffraction Limit

Centrone, Andrea

doi:10.1146/annurev-anchem-071114-040435

Cited by 237 publications

(281 citation statements)

References 155 publications

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“…Although the laser spot was large, the sharp AFM tip served as a near-field detector by locally detecting the small thermal expansion resulting from light absorption in the sample thus conferring high lateral resolution to the measurements. The resulting spatial resolution for IR mapping has been shown to be between 50 and 100 nm depending on the response of the absorbing object 23 . All IR mappings and spectra were normalized to the incident power.…”

Section: Methodsmentioning

confidence: 99%

Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

Robinet

Dazzi

Portier

et al. 2016

European Microscopy Congress 2016: Proceedings

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This paper presents the correlative imaging of collagen denaturation by nonlinear optical microscopy (NLO) and nanoscale infrared (IR) spectroscopy to obtain morphological and chemical information at different length scales. Such multiscale correlated measurements are applied to the investigation of ancient parchments, which are mainly composed of dermal fibrillar collagen. The main issue is to characterize gelatinization, the ultimate and irreversible alteration corresponding to collagen denaturation to gelatin, which may also occur in biological tissues. Key information about collagen and gelatin signatures is obtained in parchments and assessed by characterizing the denaturation of pure collagen reference samples. A new absorbing band is observed near the amide I band in the IR spectra, correlated to the onset of fluorescence signals in NLO images. Meanwhile, a strong decrease is observed in Second Harmonic signals, which are a structural probe of the fibrillar organization of the collagen at the micrometer scale. NLO microscopy therefore appears as a powerful tool to reveal collagen degradation in a non-invasive way. It should provide a relevant method to assess or monitor the condition of collagen-based materials in museum and archival collections and opens avenues for a broad range of applications regarding this widespread biological material.In museums, libraries and archives, skin is largely present in collections as rawhide, parchment or leather since it has been used for utilitarian purposes, for example in clothes, vessels, writing supports and musical instruments or for decorative purposes. In Western Europe, parchment was the main writing support in the Middle Ages up to the growth of paper production in the 14-15 th centuries. Made from an untanned animal skin, it was preserved by liming, scraping and drying the skin under tension 1 . Compared to skin, parchment retains only the dermis layer, made mostly of fibrillar collagen (type I).Among conservators and scientists involved in the preservation of cultural heritage, gelatinization is a term commonly used for parchment alteration. It refers to the collagen denaturation to gelatin, where the triple helix is dissociated. Nevertheless, little is known about the actual transformation process in parchments and the influencing factors. UV radiation, heat or pH can cause perturbations in the bonding within and in-between collagen molecules but this might not be apparent unless water comes into contact with the material. In such a damaged structure, called a "pre-gelatinized" state, the access of water to the collagen molecules is considered to cause the loss of the hydrogen bonds holding the triple helix, resulting in the unfolding of the molecule. The gelatinization resulting from the action of water is accelerated by the additional energy provided by heating 2,3 . Given that gelatinization is irreversible, the major challenge for the conservation of parchment is to identify collagen in the "pre-gelatinized" state 2,3 so that suitable treatments or cons...

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Section: Methodsmentioning

confidence: 99%

Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

Robinet

Dazzi

Portier

et al. 2016

European Microscopy Congress 2016: Proceedings

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“…In this work, two complementary atomic force microscopy (AFM)-based optical techniques, the photothermal induced resonance (PTIR) 20, 21, 22 and a novel implementation of near-field scanning optical microscopy (NSOM), 23, 24, 25 are leveraged to characterize CdTe polycrystalline solar cells with nanoscale resolution. In PTIR, a sample placed on an optically transparent prism, is illuminated in total internal reflection geometry over a relatively large area, while an AFM tip acts as a local detector for measuring absorption spectra and maps.…”

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confidence: 99%

“…20, 21, 27 In PTIR, a pulsed wavelength-tunable laser illuminates the sample and a contact AFM tip locally transduces the sample thermal expansion induced by light absorption into mechanical cantilever motion. The cantilever oscillation is detected by reflecting a diode laser off the cantilever into the AFM four-quadrant detector (figure 1a).…”

mentioning

confidence: 99%

“…For example, the grain boundaries in CdTe can assist the diffusion of S 45 and other impurities; however, grain boundary passivation 45 can impede such effect and typically leads to highly efficient CdTe devices. 46 The PTIR resolution can be a complex function of the sample thermo-mechanical properties, 21, 47 thickness and material interphases. 48 Although for thin and mechanically soft samples the spatial resolution can be better than the sample thickness (down to 20 nm, limited by the tip size); 27 for the mechanically rigid samples studied here, the PTIR resolution may be limited by the sample thickness 47 and may not be sufficient to resolve the details at the grain boundaries.…”

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confidence: 99%

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Nanoscale imaging and spectroscopy of band gap and defects in polycrystalline photovoltaic devices

et al. 2017

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Improving the power conversion efficiency of photovoltaic (PV) devices is challenging because the generation, separation and collection of electron-hole pairs are strongly dependent on details of the nanoscale chemical composition and defects which are often poorly known. In this work, two novel scanning probe nano-spectroscopy techniques, direct-transmission near-field scanning optical microscopy (dt-NSOM) and photothermal induced resonance (PTIR), are implemented to probe the distribution of defects and the bandgap variation in thin lamellae extracted from polycrystalline CdTe PV devices. dt-NSOM provides high-contrast spatially-resolved maps of light transmitted through the sample at selected wavelengths. PTIR provides absorption maps and spectra over a broad spectral range, from visible to mid-infrared. Results show variation of the bandgap through the CdTe thickness and from grain to grain that is spatially uncorrelated with the distributions of shallow and deep defects.

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“…Investigators have also used a subwavelength tip probe (91) for nanoscale measurements. Use of nanoscale imaging systems (92) in research to identify molecular changes is likely imminent, but clinical applications may not be practical in the near future.…”

Section: Molecular Digital Pathologymentioning

confidence: 99%

Emerging Themes in Image Informatics and Molecular Analysis for Digital Pathology

Bhargava

Madabhushi

2016

Annu. Rev. Biomed. Eng.

122

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Pathology is essential for research in disease and development, as well as for clinical decision making. For more than 100 years, pathology practice has involved analyzing images of stained, thin tissue sections by a trained human using an optical microscope. Technological advances are now driving major changes in this paradigm toward digital pathology (DP). The digital transformation of pathology goes beyond recording, archiving, and retrieving images, providing new computational tools to inform better decision making for precision medicine. First, we discuss some emerging innovations in both computational image analytics and imaging instrumentation in DP. Second, we discuss molecular contrast in pathology. Molecular DP has traditionally been an extension of pathology with molecularly specific dyes. Label-free, spectroscopic images are rapidly emerging as another important information source, and we describe the benefits and potential of this evolution. Third, we describe multimodal DP, which is enabled by computational algorithms and combines the best characteristics of structural and molecular pathology. Finally, we provide examples of application areas in telepathology, education, and precision medicine. We conclude by discussing challenges and emerging opportunities in this area.

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Infrared Imaging and Spectroscopy Beyond the Diffraction Limit

Cited by 237 publications

References 155 publications

Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

Nanoscale imaging and spectroscopy of band gap and defects in polycrystalline photovoltaic devices

Emerging Themes in Image Informatics and Molecular Analysis for Digital Pathology

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