The development of new effective cancer treatment methods has attracted much attention, mainly du... more The development of new effective cancer treatment methods has attracted much attention, mainly due to the limited efficacy and considerable side effects of currently used cancer treatment methods such as radiation therapy and chemotherapy. Photothermal therapy based on the use of plasmonically resonant metallic nanoparticles has emerged as a promising technique to eradicate cancer cells selectively. In this method, plasmonic nanoparticles are first preferentially uptaken by a tumor and then selectively heated by exposure to laser radiation with a specific plasmonic resonant wavelength, to destroy the tumor whilst minimizing damage to adjacent normal tissue. However, several parameters can limit the effectiveness of photothermal therapy, resulting in insufficient heating and potentially leading to cancer recurrence. One of these parameters is the patient’s pain sensation during the treatment, if this is performed without use of anesthetic. Pain can restrict the level of applicable la...
Biophotonics Congress: Biomedical Optics Congress 2018 (Microscopy/Translational/Brain/OTS), 2018
We present a TCSPC camera based compact time domain diffuse Raman instrumentation for depth probi... more We present a TCSPC camera based compact time domain diffuse Raman instrumentation for depth probing of diffusive media by time gating Raman photons. A compact non-contact probe was developed and demonstrated on tissue mimicking phantoms.
Additional file 1: Table S1. List of the main semiconductor and mineral pigments that can be foun... more Additional file 1: Table S1. List of the main semiconductor and mineral pigments that can be found in modern paintings. For every pigment is reported (i) the general name, (ii) the chemical formula and the crystal structure, (iii) the band gap energy in eV (and the corresponding wavelength/nm) known from literature. (iv) and (v) report the near-band-edge (NBE) and trap state (TS) wavelength emission under near UV excitation, respectively. (vi) the origin of trap state emission as found in literature. Figure S1. Raman spectrum of Layer 1 in sample L5 detected with the grating 600Ă‚ lpmm in the spectral range 200Ă¢ 2000 cmĂ¢ 1. It shows the presence Lead chromate (354(s-br), 375(sh-m), 839(vs)) and Phthalocyanine Blue. Blue numbers highlights the Raman bands used for the identification of Phthalocyanine blue (256(m), 679(s), 746(s) 951(m), 1143(m), 1337(s), 1448(m), 1523(vs)).
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media.... more We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212Â ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106Â ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2019
A complementary multi-analytical in-situ approach has been adopted for the investigation of a cor... more A complementary multi-analytical in-situ approach has been adopted for the investigation of a corpus of ten paintings dating from 1889 and 1940 by the Venetian painter Alessandro Milesi (1856-1945), from the collection of the International Gallery of Modern Art Ca' Pesaro in Venice. Analyses were performed in situ with digital imaging, elemental and spectroscopic analysis. The analysis of pigments and binding media and their possible deterioration patterns were studied with a combination of X-Ray Fluorescence (XRF) Spectroscopy, External Reflection- Fourier Transform Infrared Spectroscopy (ER-FTIR) and Raman Spectroscopy. These analytical methods provide information regarding the evolution of the artist's palette and the painting techniques adopted in painting. Data suggest the widespread detection of zinc carboxylates, with implications for conservation and display.
This study presents advances in the application of laser-based methods to image and measure the l... more This study presents advances in the application of laser-based methods to image and measure the luminescence lifetime of historical wall paintings containing Egyptian blue. Samples from Tel Kabri, a major Canaanite palace dated to 18th C. BCE, from the Roman city of Caesarea Maritima, from the 4–5th C. Byzantine tomb in Lohamei HaGeta'ot, and from a 6th C. Byzantine church of Shivta have been studied using time-resolved photoluminescence spectroscopy and imaging. Taking into account the high sensitivity of the emission lifetime to the microenvironment surrounding the emitting species, here, we show for the first time that the optical emission from historical samples containing Egyptian blue particles exhibits meaningful lifetime variations. Indeed, the wall paintings from Tel Kabri, Lohamei HaGeta'ot, and Shivta present the shortest emission lifetime, close to 115–120 Î¼s. However, samples from Caesarea Maritima wall paintings exhibit a different optical emission, which dumps more slowly with an average lifetime of 130 Î¼s. Egyptian blue pigment particles, synthetised with modern methods, are associated with the longest emission lifetime of 147 Î¼s. This study suggests that there is a possible link between the lifetime of the pigment's emission and its synthesis method
Abstract This work proposes a non-destructive multi-analytical approach, based on Raman and photo... more Abstract This work proposes a non-destructive multi-analytical approach, based on Raman and photoluminescence mapping to characterize the constituent materials and the stratigraphy of a multi-layer sample from a 19th century sculpture by Pompeo Marchesi. The study exploits a macro-Raman device, capable of mapping heterogeneities on a scale from sub mm2 to cm2 without the need for refocusing. The combination of the macro-Raman probe with a more conventional micro-probe improves the quality of Raman spectra and allows the material identification with a high level of confidence. Time-resolved photoluminescence microscopy allows the mapping of photoluminescent centres in the micro-sample, ascribed to crystal defects in inorganic materials. The proposed combination of optical analytical techniques provides an in-depth characterization of the constituent materials of the sample, yielding insights on its conservation history. The protocol could be potentially extended to the analysis of cross-sections of paintings.
Abstract This works presents the analysis of polychrome objects using transportable instrumentati... more Abstract This works presents the analysis of polychrome objects using transportable instrumentation for the analysis and characterisation of the palette of Ancient Egyptian Objects from a Late-period coffin in the Egyptian Museum in Cairo, with a focus both on practical details of measurements and specific results from imaging and point-like analyses. Multispectral imaging was combined with X-ray fluorescence, Raman and Photoluminescence spectroscopies. All instrumentation was transported to the museum and analysis was carried out in situ within the Conservation Laboratory. Results demonstrate the strength of imaging for mapping the presence of Egyptian Blue and mixtures of the pigment, while elemental and molecular analyses indicate the presence of mixtures of pigments to create greens, and the selective use of yellow earth or yellow ochre. In situ analysis informed sampling to determine the type of wood used and the stratigraphy of the multiple layers of white pigments and cloth used to create the ground on which the painting was executed.
The development of new effective cancer treatment methods has attracted much attention, mainly du... more The development of new effective cancer treatment methods has attracted much attention, mainly due to the limited efficacy and considerable side effects of currently used cancer treatment methods such as radiation therapy and chemotherapy. Photothermal therapy based on the use of plasmonically resonant metallic nanoparticles has emerged as a promising technique to eradicate cancer cells selectively. In this method, plasmonic nanoparticles are first preferentially uptaken by a tumor and then selectively heated by exposure to laser radiation with a specific plasmonic resonant wavelength, to destroy the tumor whilst minimizing damage to adjacent normal tissue. However, several parameters can limit the effectiveness of photothermal therapy, resulting in insufficient heating and potentially leading to cancer recurrence. One of these parameters is the patient’s pain sensation during the treatment, if this is performed without use of anesthetic. Pain can restrict the level of applicable la...
Biophotonics Congress: Biomedical Optics Congress 2018 (Microscopy/Translational/Brain/OTS), 2018
We present a TCSPC camera based compact time domain diffuse Raman instrumentation for depth probi... more We present a TCSPC camera based compact time domain diffuse Raman instrumentation for depth probing of diffusive media by time gating Raman photons. A compact non-contact probe was developed and demonstrated on tissue mimicking phantoms.
Additional file 1: Table S1. List of the main semiconductor and mineral pigments that can be foun... more Additional file 1: Table S1. List of the main semiconductor and mineral pigments that can be found in modern paintings. For every pigment is reported (i) the general name, (ii) the chemical formula and the crystal structure, (iii) the band gap energy in eV (and the corresponding wavelength/nm) known from literature. (iv) and (v) report the near-band-edge (NBE) and trap state (TS) wavelength emission under near UV excitation, respectively. (vi) the origin of trap state emission as found in literature. Figure S1. Raman spectrum of Layer 1 in sample L5 detected with the grating 600Ă‚ lpmm in the spectral range 200Ă¢ 2000 cmĂ¢ 1. It shows the presence Lead chromate (354(s-br), 375(sh-m), 839(vs)) and Phthalocyanine Blue. Blue numbers highlights the Raman bands used for the identification of Phthalocyanine blue (256(m), 679(s), 746(s) 951(m), 1143(m), 1337(s), 1448(m), 1523(vs)).
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media.... more We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212Â ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106Â ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2019
A complementary multi-analytical in-situ approach has been adopted for the investigation of a cor... more A complementary multi-analytical in-situ approach has been adopted for the investigation of a corpus of ten paintings dating from 1889 and 1940 by the Venetian painter Alessandro Milesi (1856-1945), from the collection of the International Gallery of Modern Art Ca' Pesaro in Venice. Analyses were performed in situ with digital imaging, elemental and spectroscopic analysis. The analysis of pigments and binding media and their possible deterioration patterns were studied with a combination of X-Ray Fluorescence (XRF) Spectroscopy, External Reflection- Fourier Transform Infrared Spectroscopy (ER-FTIR) and Raman Spectroscopy. These analytical methods provide information regarding the evolution of the artist's palette and the painting techniques adopted in painting. Data suggest the widespread detection of zinc carboxylates, with implications for conservation and display.
This study presents advances in the application of laser-based methods to image and measure the l... more This study presents advances in the application of laser-based methods to image and measure the luminescence lifetime of historical wall paintings containing Egyptian blue. Samples from Tel Kabri, a major Canaanite palace dated to 18th C. BCE, from the Roman city of Caesarea Maritima, from the 4–5th C. Byzantine tomb in Lohamei HaGeta'ot, and from a 6th C. Byzantine church of Shivta have been studied using time-resolved photoluminescence spectroscopy and imaging. Taking into account the high sensitivity of the emission lifetime to the microenvironment surrounding the emitting species, here, we show for the first time that the optical emission from historical samples containing Egyptian blue particles exhibits meaningful lifetime variations. Indeed, the wall paintings from Tel Kabri, Lohamei HaGeta'ot, and Shivta present the shortest emission lifetime, close to 115–120 Î¼s. However, samples from Caesarea Maritima wall paintings exhibit a different optical emission, which dumps more slowly with an average lifetime of 130 Î¼s. Egyptian blue pigment particles, synthetised with modern methods, are associated with the longest emission lifetime of 147 Î¼s. This study suggests that there is a possible link between the lifetime of the pigment's emission and its synthesis method
Abstract This work proposes a non-destructive multi-analytical approach, based on Raman and photo... more Abstract This work proposes a non-destructive multi-analytical approach, based on Raman and photoluminescence mapping to characterize the constituent materials and the stratigraphy of a multi-layer sample from a 19th century sculpture by Pompeo Marchesi. The study exploits a macro-Raman device, capable of mapping heterogeneities on a scale from sub mm2 to cm2 without the need for refocusing. The combination of the macro-Raman probe with a more conventional micro-probe improves the quality of Raman spectra and allows the material identification with a high level of confidence. Time-resolved photoluminescence microscopy allows the mapping of photoluminescent centres in the micro-sample, ascribed to crystal defects in inorganic materials. The proposed combination of optical analytical techniques provides an in-depth characterization of the constituent materials of the sample, yielding insights on its conservation history. The protocol could be potentially extended to the analysis of cross-sections of paintings.
Abstract This works presents the analysis of polychrome objects using transportable instrumentati... more Abstract This works presents the analysis of polychrome objects using transportable instrumentation for the analysis and characterisation of the palette of Ancient Egyptian Objects from a Late-period coffin in the Egyptian Museum in Cairo, with a focus both on practical details of measurements and specific results from imaging and point-like analyses. Multispectral imaging was combined with X-ray fluorescence, Raman and Photoluminescence spectroscopies. All instrumentation was transported to the museum and analysis was carried out in situ within the Conservation Laboratory. Results demonstrate the strength of imaging for mapping the presence of Egyptian Blue and mixtures of the pigment, while elemental and molecular analyses indicate the presence of mixtures of pigments to create greens, and the selective use of yellow earth or yellow ochre. In situ analysis informed sampling to determine the type of wood used and the stratigraphy of the multiple layers of white pigments and cloth used to create the ground on which the painting was executed.
This work presents recent developments in spatially offset and transmission Raman spectroscopy fo... more This work presents recent developments in spatially offset and transmission Raman spectroscopy for noninvasive detection and depth prediction of a single SERS inclusion located deep inside ex vivo biological tissues. The concept exploits the differential attenuation of Raman bands brought about by their different absorption due to tissue constituents enabling to predict the inclusion depth. Four different calibration models are tested and evaluated to predict the depth of surface enhanced Raman scattering labelled nanoparticles, within an up to 40 mm slab of porcine tissue. An external measurement carried out in transmission mode, with a noninvasively built model on the analysed sample, is shown to be insensitive to variations of the overall thickness of the tissue yielding an average root-mean-square error of prediction of 6.7{\%}. The results pave the way for future noninvasive deep Raman spectroscopy in vivo enabling to localise cancer biomarkers for an early diagnosis of multiple diseases.
We propose a non-invasive approach for the study of illuminated manuscripts based on the combinat... more We propose a non-invasive approach for the study of illuminated manuscripts based on the combination of near-infrared reflectance imaging, X-ray fluorescence mapping, and Raman spectroscopy. Taking advantage of the different absorption coefficient of the characteristic X-ray emission lines of a specific element, we have implemented a differential mapping method to distinguish the X-ray emissions from two paint layers of a manuscript. This approach was applied to a coat-of-arms of a precious illuminated manuscript belonging to the Trivulziana library collection and revealed specific patterns through the mapping of the spatial distribution of lead in different paint layers. Multivariate methods, including principal component analysis and non-negative matrix factorization, applied to the X-ray fluorescence mapping dataset demonstrate the spatial correlation between different elements. The use of complementary Raman and X-ray fluorescence spectroscopy has hence permitted the identification of the pigments employed in the original and overpainting layers found on the coat-of-arms. Through analysis, it was possible to identify the patron of the Salterium, attributed to Fracesco dei librai, as 15th C. bishop Bernardo de' Rossi.
\textcopyright} 2016, Springer-Verlag Berlin Heidelberg. While the photophysical properties of Zn... more \textcopyright} 2016, Springer-Verlag Berlin Heidelberg. While the photophysical properties of ZnO nanostructures have been widely explored, less research has focused on the bulk material present in artist pigments. This study is based on the analysis of historical pastels, representative of artist materials available at the turn of the twentieth century, and of the pure powder pigment as the control sample. The study of the intensity of the photoluminescence emission as a function of the fluence and of the nanosecond and microsecond emission decay kinetic properties allows the elucidation of the emission mechanisms in control ZnO and historical samples containing ZnO. Data suggest that in historical samples the near-band-edge free-exciton photoluminescence emission, typically occurring in the pure semiconductor, is influenced by the interaction of the pigment with surrounding organic binding material. Conversely, crystal defects, typically expected in historical samples following the imperfect synthesis process available at the beginning of the twentieth century, introduce minor modifications to the photoluminescence emission. The study further suggests that zinc carboxylates, detected in all historical samples and known to introduce characteristic groups on the surface of ZnO, could be responsible for changes in emission mechanisms. Research demonstrates how photoluminescence decay kinetics and the study of the dependence of the emission intensity on the fluence are powerful methods for elucidating the nature of the mechanism processes in luminescent semiconductor pigments.
\textcopyright} 2018 Elsevier Ltd This work reports the analysis of the time-resolved photolumine... more \textcopyright} 2018 Elsevier Ltd This work reports the analysis of the time-resolved photoluminescence behaviour on the nanosecond and microsecond time scale of fourteen historical and contemporary titanium white pigments. The pigments were produced with different production methods and post-production treatments, giving rise to a remarkable variability of titanium dioxide powders and, in some cases, to the formation of a complex surface of the crystal agglomerates. The pigments have been further characterized by Raman spectroscopy, scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy and inductively coupled plasma atomic emission spectrometry. Our study provides a clear view of the main features of the photoluminescence (PL) emission of anatase- and rutile-based pigments. For both the polymorphs of titanium dioxide the room-temperature photoluminescence emission is complex and involves different relaxation paths, related to shallow levels close to the conduction bands and mid-gap trap states. The PL behaviour appears to be little affected by post-production treatments such as organic and inorganic coatings. Instead, the presence of niobium impurities in the TiO 2 crystal lattice, as residues of the sulphate synthesis process, induce a remarkable quenching of the visible emission of anatase-based pigments. We confirm that rutile-based and anatase-based pigments are significantly different in terms of photoluminescence behaviour. This clear distinction is a valuable point for non-invasive pigment identification by in-situ photoluminescence spectroscopy. In particular, while many organic binding media emit in the visible region, the near-infrared emission of rutile is specific and can likely be used to identify the pigment in more complex materials as paints. This research paves the way to future studies of the photo-physical properties of titanium white pigments, which is imperative to understand the risk of degradation induced by the well-known photocatalytic activity of this widely used 20 th century pigment.
\textcopyright} 2017 Elsevier Ltd This works presents the analysis of polychrome objects using tr... more \textcopyright} 2017 Elsevier Ltd This works presents the analysis of polychrome objects using transportable instrumentation for the analysis and characterisation of the palette of Ancient Egyptian Objects from a Late-period coffin in the Egyptian Museum in Cairo, with a focus both on practical details of measurements and specific results from imaging and point-like analyses. Multispectral imaging was combined with X-ray fluorescence, Raman and Photoluminescence spectroscopies. All instrumentation was transported to the museum and analysis was carried out in situ within the Conservation Laboratory. Results demonstrate the strength of imaging for mapping the presence of Egyptian Blue and mixtures of the pigment, while elemental and molecular analyses indicate the presence of mixtures of pigments to create greens, and the selective use of yellow earth or yellow ochre. In situ analysis informed sampling to determine the type of wood used and the stratigraphy of the multiple layers of white pigments and cloth used to create the ground on which the painting was executed.
We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media.... more We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0{\&}{\#}x2013;212{\&}{\#}x00A0;ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106{\&}{\#}x00A0;ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.
\textcopyright} 2017 WILEY-VCH Verlag GmbH {\&} Co. KGaA, Weinheim Anthracenyl boronic acid deriv... more \textcopyright} 2017 WILEY-VCH Verlag GmbH {\&} Co. KGaA, Weinheim Anthracenyl boronic acid derivatives are used for the first time as hydrogen-bond and $\pi$-donors to obtain a series of novel 1:1 mixed stacked $\pi$-organic materials with interesting structural, UV/Vis reflectance and emission properties by reaction with quinones in both solution and the solid. The underlying principles, which have led to hetero-assembly, could be applied to construct a potentially large variety of mixed stacked $\pi$-organic solid-state materials for technological applications.
\textcopyright} OSA 2018. We present a TCSPC camera based compact time domain diffuse Raman instr... more \textcopyright} OSA 2018. We present a TCSPC camera based compact time domain diffuse Raman instrumentation for depth probing of diffusive media by time gating Raman photons. A compact non-contact probe was developed and demonstrated on tissue mimicking phantoms.
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