projects
A3TEX
Research in Spectroscopy for Textile Heritage Conservation
Dr. Alessandro Ciccola’s main research is aimed in the innovative application of spectroscopic methods for the characterization of objects of art and historical interest, in agreement with the main principles of non-invasiveness and non-destructivity, fundamental for the conservation of Cultural Heritage.
The spectroscopic approach has a long history for the diagnostic application in conservation, providing a wide set of information from complex matrices, such as paintings and textiles, with a minimum risk for the art objects: most of the spectroscopic approaches, in fact, can be considered non-destructive, while the innovation in this field allowed the increase of portable spectroscopic setups, utilisable directly on excavations or exposition sites.
According to the wavelength of used radiation, different information could be obtained from the same samples in terms of chemical composition and physical properties, which makes these approaches highly exploitable not only for characterisation of historical objects but also for testing of new conservation materials and solutions.
Why Study Ancient Dyes?
Textiles have played a crucial role in human history, serving not just as everyday materials but also as symbols of status, trade, and artistic expression. The colors used in ancient fabrics tell us about the resources, techniques, and even the cultural connections between civilizations. However, identifying these dyes is a challenge: they are present in tiny amounts, degrade over time, and often require invasive sampling methods that can damage valuable artifacts.
A breakthrough technique, Gel-Supported Liquid Extraction (GSLE) combined with Surface-Enhanced Raman Scattering (SERS), is now changing the way we study ancient textiles. This research, led by Alessandro Ciccola and his team, applies this innovative method to Tutankhamun’s textiles, offering new insights into the dyes used over 3,000 years ago while ensuring the preservation of these fragile treasures.
By combining cutting-edge technology with cultural heritage studies, this research ensures that we can unlock the secrets of the past while preserving them for future generations.
project .01
Unlocking the Secrets of Ancient Textiles: Gel-Supported Liquid Extraction (GSLE) for Surface-Enhanced Raman Scattering (SERS) Analysis of Dyes
Introduction
In the last years, ground-breaking research of Dr. Ciccola has been devoted to the development of new analytical protocols based on the combination of Gel Supported Liquid Extraction with Surface Enhanced Raman Scattering spectroscopy for the identification of dyes and colorants in traces. GSLE exploits the use of hydrogel and polymers, properly loaded with solutions, to extract locally on complex artifacts in limited areas, just by simple contact with the object surface. In particular, the use of sustainable gels based on polysaccharides resulted particularly compatible for the extraction of dyes from very complex matrices, such as paintings and textiles. Moreover, this extraction approach presents the main advantage of being highly micro-invasive, substituting the mechanical sampling and consequently minimizing the conservation risks. This extraction approach is even highly versatile, because the hydrogels are loadable with different typologies of extraction solutions, extending the range of analytes.
The methodology can be interfaced with spectroscopic characterization methods, and, in particular, with Surface Enhanced Raman Scattering spectroscopy. This technique is based on the enhancement of Raman scattering signal by contact of the noble metal nanoparticles with the dyes entrapped in the gel matrix and it allows reaching very high sensitivity, allowing the identification of analytes in traces. Moreover, this spectroscopic approach is highly powerful in the case of dyes, which strengthens the suitability for the identification of colorant species in ancient textiles.
The combination with GSLE was extensively tested on different typologies of natural dyes and complex pictorial and textile matrices, resulting in the clear identification of the main chromophores of the dye in traces with no eye-visible change on the investigated matrix. This approach grants for the achievement of high quality analytical results with no effect on the analysed object. Moreover, it can be combined with further analytical strategies, such as re-extraction for later chromatographic analysis, conducted in collaboration with Dr. Ilaria Serafini.
Study Framework
Objectives
- Design an analytical protocol non-invasive on the eye scale, for the localized extraction of dyes from paintings and textile.
- Exploit Surface Enhanced Raman Scattering spectroscopy for the trace identification of dyes after extraction from art objects with no visible change.
- Evaluate the versatility of the approach for several natural and synthetic dyes from historical painting and textile matrices.
Methodologies
GSLE involves using soft gels, such as agar or Nanorestore Gel® High Water Retention (HWR), which gently extract dye molecules from a surface without damaging the material. The process works as follows:
Gel Preparation – The gel is cut into small pieces and soaked in a special solution that helps extract dyes from the textile.
Application on the Textile – The gel is placed on the surface of the ancient fabric, allowing the dyes to migrate into the gel.
Analysis with SERS – Silver nanoparticles are added to the gel, enhancing the weak dye signals and allowing researchers to identify them using Raman spectroscopy.
Data Interpretation – The dye spectra are compared with known references to determine which pigments were used in the past.
This approach preserves the integrity of the textile, requires no destructive sampling, and is highly effective for detecting even faint traces of ancient dyes.
Results
- High sensitivity and low risk: The methodology allows reaching very high sensitivity with no risk for the conservation of the objects (no mechanical sampling is involved), while the use of water-based extraction methods and sustainable gels represent an important aspect of sustainability.
- Low invasiveness: The method showed a general non-invasiveness on the eye-scale, granting for low risk conservative operations.
- Versatility and efficiency: The new protocol was proficiently applied on several art objects, such as textiles from the Tutankhamun tomb and historical paint catalogues. Its versatility was evidenced by the successful individuation of both natural and synthetic dyes Traditional dye analysis often requires taking small fabric samples, but when dealing with rare and delicate artifacts—such as textiles from King Tutankhamun’s tomb—conservators need a method that is minimally invasive and highly precise.
The Tutankhamun Case Study: What Did the Ancient Egyptians Use?
The discovery on 1922 of the little-known Pharaoh Tutankhamun’s tomb by the British archaeologist Howard Carter provided an unprecedented glimpse into royal Egyptian garments from the 18th Dynasty. The preservation of textiles within the tomb was remarkable, offering insights into the materials and dyes dating back to 1325 BCE. However, analyzing these ancient fabrics posed significant challenges due to the delicate nature of the materials and the potential for damage using traditional sampling methods.
The GSLE and SERS integrated technique has been successfully applied to textiles from Tutankhamun’s tomb, identifying ancient dyes non-destructively, thus allowing archaeologists and conservation scientists to better understand and protect historical textiles.
Objectives and Methodology of the case study
The research aimed to achieve several key objectives:
- Develop a micro-invasive analytical protocol for the localized extraction of dyes from textiles and paintings.
- Utilize Surface-Enhanced Raman Scattering (SERS) for the identification of dye traces without visibly altering the artifact.
- Assess the versatility of the method for various types of natural and synthetic dyes.
Application of GSLE and SERS to Tutankhamun’s Textiles
1. Sample Selection and Preparation
- The analyzed linen fragment originated from Tutankhamun’s tomb and contained colored areas in blue and red.
- Before extraction, Fiber Optic Reflectance Spectroscopy (FORS) was performed to obtain a preliminary identification of the dyes, allowing the selection of the most suitable extraction method.
2. Extraction Process with GSLE
- Two types of gel were used:
- Agar gel with concentrations between 2% and 4%.
- Nanorestore Gel® High Water Retention (HWR).
- The extractions were carried out using specific solutions:
- For red dyes (likely madder, Rubia tinctorum): an ammonia-EDTA-NaCl-based solution.
- For blue dyes (likely indigo, Indigofera tinctoria): a reducing solution of NaOH/Na₂S₂O₄.
3. Identification with SERS
- After extraction, SERS analyses confirmed the presence of indigo in the blue area and madder in the red area.
- Raman signals also revealed degradation products of indigo, including indirubin and anthranilic acid, suggesting chemical alteration phenomena of the original dye.
What Did the GSLE – SERS integrated Analysis of the Pharao Tutankhamun’s Tomb reveal?
The GSLE + SERS approach allowed for the detection of dyes at very high sensitivity levels without the need for mechanical sampling. The use of water-based extraction methods and sustainable gels contributed to the preservation of the artifacts, making this method an eco-friendly and non-invasive alternative to traditional dye analysis techniques.
The linen fragments, once part of Tutankhamun’s burial textiles, revealed two dominant colors: blue and red. The first step was to apply Fiber Optic Reflectance Spectroscopy (FORS), a preliminary non-invasive technique that provided clues about the possible composition of the dyes. Based on these findings, two distinct extraction solutions were prepared—one for the red dyes and one for the blue.
In the blue-dyed sections, the analysis confirmed the presence of indigo (Indigofera tinctoria), a dye known for its deep, rich hue and widespread use in antiquity. However, the SERS signals revealed more than just the original pigment—traces of indirubin and anthranilic acid were also detected. These compounds, known degradation products of indigo, suggested that the dye had undergone natural chemical transformations over millennia, subtly altering its original vibrancy. This finding not only confirmed the ancient Egyptians’ advanced dyeing techniques but also provided insight into how these materials evolved over time under burial conditions.
The red-dyed fragments told another compelling story. The analysis identified madder (Rubia tinctorum) as the primary source of the red pigment. The spectral fingerprint of madder matched perfectly with reference samples, confirming that the ancient artisans had used plant-based dyes rich in alizarin and purpurin, key chromophores responsible for its striking red hue. Unlike the blue dye, the red pigment appeared remarkably well-preserved, suggesting that the burial environment may have played a role in its stability over time.
Moreover, this study highlighted the potential of this combined technique for future applications—whether in the study of other archaeological textiles, historical paintings, or delicate manuscripts. The ability to detect degradation products of dyes adds another layer of understanding, shedding light on how colors evolved through time due to environmental and chemical factors.
project .02
Identification of dyes and organic pigments by means of multi-technical approaches
Overview
Under the supervision of prof. Armandoriano Bianco and prof. Marcella Guiso, Dr. Serafini and Dr. Ciccola devoted their past research on development of new analytical protocols for the characterization of natural dyes and synthetic organic pigments, along with the study of ageing in natural fibers and synthetic binders. In these projects, new mild extraction methods for natural dyes were developed, applied for both the characterization of natural dye matrices and the identification of these species in ancient textiles.
Several spectroscopic methods were applied, from the mono-dimensional and bi-dimensional Nuclear Magnetic Resonance spectroscopy for the identification of dye structures and the characterisation of acrylic binder degradation products, to the use Fiber Optic Reflectance Spectroscopy for the monitoring of ageing in natural fibers and to the application FTIR and Raman spectroscopies for the identification of aged binder and organic pigments in contemporary murals.
Finally, mass spectrometry and HPLC were applied for the characterization of ancient matrices and the investigation of degradation products. The collaboration with important museums, such as the Vatican Museums and the National Gallery of Modern and Contemporary Art in Rome resulted in the construction of a versatile background in research for Cultural Heritage and diagnostics.
Study Framework
Objectives
- Design new mild extraction methods for the identification of natural and synthetic dyes.
- Exploit spectroscopic, spectrometric and chromatographic techniques for the characterisation of complex matrices of cultural interest.
- Monitor and explore the ageing of natural and synthetic species.
Methodologies
- Extraction Methods: Using extraction methods based on water and mild environment for the preservation of important analytes
- Spectroscopy and Spectrometry: Exploring the potential of spectroscopic and spectrometric approaches for the characterization of main and trace analytes in complex textile and painting matrices.
- Chromatography: Separating different analytes for the whole-integrated identification of main markers of natural matrices and their ageing products.
Results
- Mild extraction methodologies: The new ammonia-based method was effectively devoted to the characterisation of natural and synthetic dyes on different historical textiles conserved in museums.
- Ageing studies: Mechanisms of ageing in contemporary artworks were investigated and modelized, with effective correspondence in real samples.
- Diagnostics on historical objects: The research methodologies were successfully applied on different complex matrices, from mineralised textiles from Pompeii to the ancient garment of the daughter of Tomasi di Lampedusa, to Lucio Fontana’s painting and street arworks.
Industrial Scale-up and Technology Transfer Activities
Dr. Ciccola co-founded Sapienza’s start-up D-ART srl with Dr Ilaria Serafini, which offers diagnostic-analytical services in cultural heritage, including material characterization, conservation state assessment, and authenticity analysis.
The start-up provides comprehensive diagnostic projects in collaboration with various Sapienza partners and offers development and testing services for specific products and materials for conservation and restoration.
Additionally, D-ART srl extends its multi-technical analysis services to other fields, such as agri-food, cosmetics, and pharmaceuticals. Notably, the start-up has been involved in the conservation and analysis of Raffaello Sanzio’s tapestries.
Selected Publications
1. Ioele, Marcella, Ciccola, Alessandro, Postorino, Paolo (2024). The Deposition by Raffaello Sanzio: new analytical insights on old cross sections for the characterisation of pictorial palette. HELIYON, vol. 10, ISSN: 2405-8440, doi: 10.1016/j.heliyon.2024.e35597
2. Greta Peruzzi, Alessandro Ciccola, Adele Bosi, Ilaria Serafini, Martina Negozio, Nagmeldeen Morshed Hamza, Claudia Moricca, Laura Sadori, Gabriele Favero, Valentina Nigro, Paolo Postorino, Roberta Curini (2023). Applying gel-supported liquid extraction to Tutankhamun’s textiles for the Identification of ancient colorants. A case study. GELS, vol. 9, p. 1-13, ISSN:2310-2861, doi: 10.3390/gels9070514
3. Ciccola A., Serafini I., D’agostino G., Giambra B., Bosi A., Ripanti F., Nucara A., Postorino P., Curini R., Bruno M. (2021). Dyes of a shadow theatre: Investigating tholu bommalu indian puppets through a highly sensitive multi-spectroscopic approach. HERITAGE, vol. 4, p. 1807-1820, ISSN: 2571-9408, doi: 10.3390/HERITAGE4030101
4. Germinario G., Ciccola A., Serafini I., Ruggiero L., Sbroscia M., Vincenti F., Fasolato C., Curini R., Ioele M., Postorino P., Sodo A. (2020). Gel substrates and ammonia-EDTA extraction solution. A new non-destructive combined approach for the identification of anthraquinone dyes from wool textiles. MICROCHEMICAL JOURNAL, vol. 155, p. 1-9, ISSN: 0026-265X, doi: 10.1016/j.microc.2020.104780
5. Ciccola, Alessandro, Serafini, Ilaria, Guiso, Marcella, Ripanti, Francesca, Domenici, Fabio, Sciubba, Fabio, Postorino, Paolo, Bianco, Armandodoriano (2019). Spectroscopy for contemporary art. Discovering the effect of synthetic organic pigments on UVB degradation of acrylic binder. POLYMER DEGRADATION AND STABILITY, vol. 159, p. 224-228, ISSN: 0141-3910, doi: 10.1016/j.polymdegradstab.2018.11.027
