Environmental Science and Pollution Research, 2016
The research complements the complex study carried out to understand the source of brown discolou... more The research complements the complex study carried out to understand the source of brown discolourations of ten marble statues in the Church of Orsanmichele in Florence, Italy. Originally located in exterior niches, the statues were restored to reverse the extensive alterations they had undergone throughout the centuries. One of the major alterations was the application of a dark brown patina that dated just after 1789. After the statues were placed indoors, brownish discolourations started to appear on their surfaces. Cross sections were examined using FTIR mapping and immunological methods. In parallel, the pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) data already obtained from the statues' scrapings were compared with data from aged casein films applied to microscope glass slides and aged milk-treated marble. All the statues had been treated with milk-based substances before the time the bronze patina was applied. The values of temperature and illumination of the room were important factors in the ageing of organic substances and in the formation of calcium oxalates. It is likely that products of thermo-oxidation and photo-oxidation of the oils together with the oxalates caused the darkening. The marble samples corresponded to a Lunense provenance.
The present review is aimed at reporting on the most advanced and recent applications of immunoch... more The present review is aimed at reporting on the most advanced and recent applications of immunochemical imaging techniques for the localization of proteins within complex and multilayered paint stratigraphies. Indeed, a paint sample is usually constituted by the superimposition of different layers whose characterization is fundamental in the evaluation of the state of conservation and for addressing proper restoration interventions. Immunochemical methods, which are based on the high selectivity of antigen-antibody reactions, were proposed some years ago in the field of cultural heritage. In addition to enzyme-linked immunosorbent assays for protein identification, immunochemical imaging methods have also been explored in the last decades, thanks to the possibility to localize the target analytes, thus increasing the amount of information obtained and thereby reducing the number of samples and/or analyses needed for a comprehensive characterization of the sample. In this review, chemiluminescent, spectroscopic and electrochemical imaging detection methods are discussed to illustrate potentialities and limits of advanced immunochemical imaging systems for the analysis of paint cross-sections.
Within the framework of the UNESCO workshops on the Conservation and Preservation of the Koguryo ... more Within the framework of the UNESCO workshops on the Conservation and Preservation of the Koguryo mural paintings which were held in Pyongyang in 2004 and 2005, paint samples were collected from several different tombs (Tokhun-ri, Yaksu-ri, Susan-ri, Jinpa-ri) located in the sub-urban Pyongyang and analyzed by optical, polarized and FTIR microscopy, environmental scanning electron microscopy coupled with energy-dispersive X-ray analysis (ESEM-EDX), X-ray diffraction (XRD), Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC-MS) as well as Raman spectroscopy in order to characterize the composition of pigments, the execution technique adopted and the murals\u2019 state of conservation. The first scientific results seem to suggest the adoption of a \u201cfresco technique\u201d, even though it\u2019s not yet clear whether it was intentionally achieved by painters. To verify this more samples need to be analysed as well as confirmation from an historical literature survey. The external surface of all the paint layers showed the presence of a recrystallized calcite layer, with embedded clayish deposits. Traces of organic materials such as waxes, silicones and natural resins (probably applied during past restoration interventions) have also been detected. The scientific examination results guided the selection of the most appropriate conservation and restoration intervention techniques
The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be... more The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be unveiled to the public after undergoing lengthy conservation. This project is at the stage where it is necessary to define environmental criteria for the long-term display of the doors. In this paper, three possible methodologies for display of the doors are considered: a showcase purged with nitrogen; a showcase with low, controlled relative humidity; an open showcase with a controlled microclimate. Galvanic sensors were used inside the cases to continuously monitor the macrocouple current of the doors and establish which case provided the most stable environment for display. Results to date indicate that the showcase with low, controlled humidity may offer the best solution for long-term display of the doors.
ABSTRACT The present research was aimed at exploiting and evaluating the potentialities of FT-NIR... more ABSTRACT The present research was aimed at exploiting and evaluating the potentialities of FT-NIR microscopy, as a complementary approach to analysis in the MIR region, for the chemical characterisation of paint cross sections. Even if FT-NIR technique is still underutilised in the field of cultural heritage investigations, the integrated use of information recorded in the NIR and in the MIR regions proved to be extremely useful in the molecular investigation of organic and inorganic substances. In fact, combination and overtone bands present in the NIR region, even if weaker and less selective than those in the MIR region, are not distorted by reflection phenomena. Furthermore, NIR spectra can be efficiently used as a spectral fingerprint for the stratigraphic characterisation of paint cross sections. The proposed analytical protocol was applied on two historical samples, presenting different stratigraphic structures. Suitable chemometric methods were applied for the elaboration of multivariate chemical maps recorded in the range 700–7500 cm− 1. In particular, a comprehensive and efficient procedure based on an interactive brushing approach, which combines the structural information of the score scatter plots with the spatial information of the PC score maps, was used. Interestingly, NIR data allowed a thorough characterisation of paint structures, providing information for the identification of components and suggesting the differentiation among different types of proteins. Moreover, NIR spectra permitted to achieve an efficient distinction of different classes of natural resins, demonstrating that, even working at a microscopic level, the NIR region may support the identification of different terpenoid materials. Multivariate analysis performed on MIR data did not provide satisfactory results, probably due to the distortion of the spectra and overlapping of bands. Nevertheless, MIR outcomes were investigated to support the interpretation of NIR spectra and in attempt to define an integrated protocol for the characterisation of complex paint mixtures.
The qualitative identification of proteinaceous substances, as well as their location within a co... more The qualitative identification of proteinaceous substances, as well as their location within a complex paint stratigraphy, is one of the most challenging issues in the characterization of painting materials. Nevertheless, information on paint components represent a crucial task for studies concerning both the ancient painting techniques adopted and the state of conservation, being fundamental investigations for the selection of appropriate conservation actions. The present research was aimed at developing a new detection approach for the immunochemical localization of ovalbumin in paint cross-sections based on the use of scanning electrochemical microscopy (SECM). The immunochemical analyses were performed using an anti-ovalbumin primary antibody and a secondary antibody labelled with horseradish peroxidase (HRP). SECM measurements were performed in feedback mode using benzoquinone (BQ)/hydroquinone (H2Q) redox couple. In presence of hydrogen peroxide (H2O2), HRP catalyzes the re-ox...
In the field of analytical chemistry, many scientific efforts have been devoted to develop experi... more In the field of analytical chemistry, many scientific efforts have been devoted to develop experimental procedures for the characterization of organic substances present in heterogeneous artwork samples, due to their challenging identification. In particular, performances of immunochemical techniques have been recently investigated, optimizing ad hoc systems for the identification of proteins. Among all the different immunochemical approaches, the use of metal nanoparticles - for surface enhanced Raman scattering (SERS) detection - remains one of the most powerful methods that has still not been explored enough for the analysis of artistic artefacts. For this reason, the present research work was aimed at proposing a new optimized and highly efficient indirect immunoassay for the detection of ovalbumin. In particular, the study proposed a new SERRS probe composed of gold nanoparticles (AuNPs) functionalised with Nile Blue A and produced with an excellent green and cheap alternative approach to the traditional chemical nanoparticles synthesis: the laser ablation synthesis in solution (LASiS). This procedure allows us to obtain stable nanoparticles which can be easily functionalized without any ligand exchange reaction or extensive purification procedures. Moreover, the present research work also focused on the development of a comprehensive analytical approach, based on the combination of potentialities of immunochemical methods and Raman analysis, for the simultaneous identification of the target protein and the different organic and inorganic substances present in the paint matrix. An advanced mapping detection system was proposed to achieve the exact spatial location of all the components through the creation of false colour chemical maps.
Environmental Science and Pollution Research, 2016
The research complements the complex study carried out to understand the source of brown discolou... more The research complements the complex study carried out to understand the source of brown discolourations of ten marble statues in the Church of Orsanmichele in Florence, Italy. Originally located in exterior niches, the statues were restored to reverse the extensive alterations they had undergone throughout the centuries. One of the major alterations was the application of a dark brown patina that dated just after 1789. After the statues were placed indoors, brownish discolourations started to appear on their surfaces. Cross sections were examined using FTIR mapping and immunological methods. In parallel, the pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) data already obtained from the statues' scrapings were compared with data from aged casein films applied to microscope glass slides and aged milk-treated marble. All the statues had been treated with milk-based substances before the time the bronze patina was applied. The values of temperature and illumination of the room were important factors in the ageing of organic substances and in the formation of calcium oxalates. It is likely that products of thermo-oxidation and photo-oxidation of the oils together with the oxalates caused the darkening. The marble samples corresponded to a Lunense provenance.
The present review is aimed at reporting on the most advanced and recent applications of immunoch... more The present review is aimed at reporting on the most advanced and recent applications of immunochemical imaging techniques for the localization of proteins within complex and multilayered paint stratigraphies. Indeed, a paint sample is usually constituted by the superimposition of different layers whose characterization is fundamental in the evaluation of the state of conservation and for addressing proper restoration interventions. Immunochemical methods, which are based on the high selectivity of antigen-antibody reactions, were proposed some years ago in the field of cultural heritage. In addition to enzyme-linked immunosorbent assays for protein identification, immunochemical imaging methods have also been explored in the last decades, thanks to the possibility to localize the target analytes, thus increasing the amount of information obtained and thereby reducing the number of samples and/or analyses needed for a comprehensive characterization of the sample. In this review, chemiluminescent, spectroscopic and electrochemical imaging detection methods are discussed to illustrate potentialities and limits of advanced immunochemical imaging systems for the analysis of paint cross-sections.
Within the framework of the UNESCO workshops on the Conservation and Preservation of the Koguryo ... more Within the framework of the UNESCO workshops on the Conservation and Preservation of the Koguryo mural paintings which were held in Pyongyang in 2004 and 2005, paint samples were collected from several different tombs (Tokhun-ri, Yaksu-ri, Susan-ri, Jinpa-ri) located in the sub-urban Pyongyang and analyzed by optical, polarized and FTIR microscopy, environmental scanning electron microscopy coupled with energy-dispersive X-ray analysis (ESEM-EDX), X-ray diffraction (XRD), Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC-MS) as well as Raman spectroscopy in order to characterize the composition of pigments, the execution technique adopted and the murals\u2019 state of conservation. The first scientific results seem to suggest the adoption of a \u201cfresco technique\u201d, even though it\u2019s not yet clear whether it was intentionally achieved by painters. To verify this more samples need to be analysed as well as confirmation from an historical literature survey. The external surface of all the paint layers showed the presence of a recrystallized calcite layer, with embedded clayish deposits. Traces of organic materials such as waxes, silicones and natural resins (probably applied during past restoration interventions) have also been detected. The scientific examination results guided the selection of the most appropriate conservation and restoration intervention techniques
The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be... more The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be unveiled to the public after undergoing lengthy conservation. This project is at the stage where it is necessary to define environmental criteria for the long-term display of the doors. In this paper, three possible methodologies for display of the doors are considered: a showcase purged with nitrogen; a showcase with low, controlled relative humidity; an open showcase with a controlled microclimate. Galvanic sensors were used inside the cases to continuously monitor the macrocouple current of the doors and establish which case provided the most stable environment for display. Results to date indicate that the showcase with low, controlled humidity may offer the best solution for long-term display of the doors.
ABSTRACT The present research was aimed at exploiting and evaluating the potentialities of FT-NIR... more ABSTRACT The present research was aimed at exploiting and evaluating the potentialities of FT-NIR microscopy, as a complementary approach to analysis in the MIR region, for the chemical characterisation of paint cross sections. Even if FT-NIR technique is still underutilised in the field of cultural heritage investigations, the integrated use of information recorded in the NIR and in the MIR regions proved to be extremely useful in the molecular investigation of organic and inorganic substances. In fact, combination and overtone bands present in the NIR region, even if weaker and less selective than those in the MIR region, are not distorted by reflection phenomena. Furthermore, NIR spectra can be efficiently used as a spectral fingerprint for the stratigraphic characterisation of paint cross sections. The proposed analytical protocol was applied on two historical samples, presenting different stratigraphic structures. Suitable chemometric methods were applied for the elaboration of multivariate chemical maps recorded in the range 700–7500 cm− 1. In particular, a comprehensive and efficient procedure based on an interactive brushing approach, which combines the structural information of the score scatter plots with the spatial information of the PC score maps, was used. Interestingly, NIR data allowed a thorough characterisation of paint structures, providing information for the identification of components and suggesting the differentiation among different types of proteins. Moreover, NIR spectra permitted to achieve an efficient distinction of different classes of natural resins, demonstrating that, even working at a microscopic level, the NIR region may support the identification of different terpenoid materials. Multivariate analysis performed on MIR data did not provide satisfactory results, probably due to the distortion of the spectra and overlapping of bands. Nevertheless, MIR outcomes were investigated to support the interpretation of NIR spectra and in attempt to define an integrated protocol for the characterisation of complex paint mixtures.
The qualitative identification of proteinaceous substances, as well as their location within a co... more The qualitative identification of proteinaceous substances, as well as their location within a complex paint stratigraphy, is one of the most challenging issues in the characterization of painting materials. Nevertheless, information on paint components represent a crucial task for studies concerning both the ancient painting techniques adopted and the state of conservation, being fundamental investigations for the selection of appropriate conservation actions. The present research was aimed at developing a new detection approach for the immunochemical localization of ovalbumin in paint cross-sections based on the use of scanning electrochemical microscopy (SECM). The immunochemical analyses were performed using an anti-ovalbumin primary antibody and a secondary antibody labelled with horseradish peroxidase (HRP). SECM measurements were performed in feedback mode using benzoquinone (BQ)/hydroquinone (H2Q) redox couple. In presence of hydrogen peroxide (H2O2), HRP catalyzes the re-ox...
In the field of analytical chemistry, many scientific efforts have been devoted to develop experi... more In the field of analytical chemistry, many scientific efforts have been devoted to develop experimental procedures for the characterization of organic substances present in heterogeneous artwork samples, due to their challenging identification. In particular, performances of immunochemical techniques have been recently investigated, optimizing ad hoc systems for the identification of proteins. Among all the different immunochemical approaches, the use of metal nanoparticles - for surface enhanced Raman scattering (SERS) detection - remains one of the most powerful methods that has still not been explored enough for the analysis of artistic artefacts. For this reason, the present research work was aimed at proposing a new optimized and highly efficient indirect immunoassay for the detection of ovalbumin. In particular, the study proposed a new SERRS probe composed of gold nanoparticles (AuNPs) functionalised with Nile Blue A and produced with an excellent green and cheap alternative approach to the traditional chemical nanoparticles synthesis: the laser ablation synthesis in solution (LASiS). This procedure allows us to obtain stable nanoparticles which can be easily functionalized without any ligand exchange reaction or extensive purification procedures. Moreover, the present research work also focused on the development of a comprehensive analytical approach, based on the combination of potentialities of immunochemical methods and Raman analysis, for the simultaneous identification of the target protein and the different organic and inorganic substances present in the paint matrix. An advanced mapping detection system was proposed to achieve the exact spatial location of all the components through the creation of false colour chemical maps.
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