Next Article in Journal
Experimental and Modelling of Lightning Damage to Carbon Fibre-Reinforced Composites under Swept Stroke
Previous Article in Journal
Replacing Toxic Hard Chrome Coatings: Exploring the Tribocorrosion Behaviour of Electroless Nickel-Boron Coatings
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Coatings
Volume 13
Issue 12
10.3390/coatings13122047
coatings-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Reversible Organic Coatings for On-Site Comprehensive Emergency Protection during Archaeological Excavations

by
Wenjin Zhang
1,2,
Kejin Shen
2,
Yaxu Zhang
3,
Xueping Chen
4,
Xichen Zhao
3,
Xiao Huang
2,* and
Hongjie Luo
1,2,*
1
School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
2
Institute for the Conservation of Cultural Heritage, Shanghai University, Shanghai 200444, China
3
Shaanxi Academy of Archeology, Xi’an 710054, China
4
School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
*
Authors to whom correspondence should be addressed.
Coatings 2023, 13(12), 2047; https://doi.org/10.3390/coatings13122047
Submission received: 26 October 2023 / Revised: 25 November 2023 / Accepted: 30 November 2023 / Published: 5 December 2023
Browse Figures
Review Reports Versions Notes

Abstract

:
Once excavated, cultural relics face immediate threats from oxidation, water loss, mold growth, etc., which are caused due to severe environmental changes. Covering with plastic films, spraying water, or applying biocides followed by mechanical polish are common conservation practices, which are effective to some extent, but with obvious side effects. Menthol, often used as volatile binding material (VBM) in heritage conservation, has been proved to be safe to conservators and cultural relics and can be removed easily via sublimation with no residue. In this study, the possibility of using menthol coatings as a reversible environmental barrier to protect cultural relics during excavation is examined. Laboratory results show that menthol coating has an excellent ability to prevent oxygen and water molecules from passing through it, to stop various fungal growths and cut off radiation below 300 nm. On-site antifungal applications on a mural tomb of the Tang Dynasty, located in the north of Xi’an Xianyang International Airport, provided satisfactory results. Laboratory and field results show that menthol coating has high potential of being used for the emergency protection of relics against sudden environmental changes during excavation.

1. Introduction

A high number of cultural heritage sites are buried underground worldwide. After hundreds of years of being underground, these cultural heritage sites have reached a physical and chemical equilibrium with their surrounding environment. However, once they are excavated, the cultural heritage sites face drastic environmental changes, including but not limited to those associated with temperature, humidity, light, air, etc. [1,2]. Such sudden environmental changes often lead to the catastrophic destruction of cultural heritage sites [3].
The water content of some cultural relics changes drastically when they are excavated [2,4,5]. For example, the polychrome of Emperor Qin Shihuang terracotta warriors will lose water in just a few minutes after excavation, which causes the warping and deformation of the polychrome [6]. Some metal cultural relics will be oxidized rapidly when exposed to air, resulting in severe physical damage and changes in chemical ingredients, and the presence of water will accelerate such changes [7,8,9,10]. Illumination can cause the irreversible degradation of cultural relics. All these environmental factors often jointly affect the excavated cultural relics [11]. The germination and growth of microorganisms are also strongly affected by environmental changes and show an obvious negative impact on cultural relics [12,13,14,15,16,17]. It is also found that biological synergistic effects may cause more severe damage to cultural relics [18].
As mentioned above, the deterioration of cultural relics during excavation caused by sudden environmental changes is fast and is affected by multiple factors. Therefore, it is necessary to develop a simple, easy-to-proceed technology that can be applied during on-site excavation. Such technology should meet a few basic criteria. First, it should be safe for cultural relics, conservators, and the environment. Second, the material used in this technology should be easy to remove and should not influence future archaeological research and conservation work at that site. Meanwhile, it is better to be multifunctional to meet the minimum intervention principle of cultural relics conservation, as at present, the ideal technology for archaeological excavations does not exist.
Currently, on archaeological excavation sites, various treatments are applied for different environmental factors [19,20,21,22]. For instance, water spray is often used to hydrate cultural relics that are sensitive to dehydration, biocides are used to inhibit the germination and growth of microorganisms when needed, and plastic films are used to cover relics to protect them from dust and direct sunlight. These treatments have certain protective effects with obvious side effects. For instance, humidification and film covering often promote microorganism growth, while there are often residues or safety issues associated with cultural relics when biocides are used [23,24,25].
Menthol, a natural cyclic monoterpene alcohol extracted from plants, has been used as a reversible enhancement material for fragile cultural relics during excavation. Its safety and reversibility have been evaluated systematically [26,27,28]. In this study, the possibility of using menthol coatings as an environmental barrier and a universal antifungal agent on cultural relics during excavation is investigated.

2. Experimental

2.1. Materials

Penicillium polonicum K.M. Zalessky and Aspergillus niger were purchased from Biobw Co. (Beijing, China) and maintained in PDA (Potato Dextrose Agar) slant medium at 4 °C. PDA and PDB (Potato Dextrose Broth) media were purchased from Merck Co. L-Menthol (purity ≥ 98%) was purchased from Aldrich. All materials were used as received.

2.2. Methods

2.2.1. Environmental Barrier Experiment

All experiments were performed at 25 °C and 70% RH (relative humidity).
In a glove box, oxygen indicators (C-22, Mitsubishi Gas Chemical Co., Inc., Tokyo, Japan) were coated with melted menthol. The samples were taken out of the glove box once melted menthol solidified and were placed in an open environment at room temperature for 0.5, 3, 6, 24, 48 h, and 7 d to observe the oxidation of the oxygen indicator, respectively. The menthol coating was about 3 mm in thickness.
A 10 mL volume of deionized water was placed in a 10 mL graduated cylinder. Melted menthol was added to form a 3 mm thick seal on the water surface. The water evaporation was observed at 48 h intervals at room temperature in an open environment and compared with the uncoated reference sample for up to 30 days.
In another set of experiments, melted menthol was added on pH indicator strips to form an approximately 1 mm thick layer of coating on the surface. Then, 0.1 M HCl or 0.1 M NaOH aqueous solution was applied.

2.2.2. Antifungal Evaluation of Mock-Up Samples in Laboratory

The preparation of spore suspensions and mock-up samples are described as follows [23]. After the activation of Penicillium polonicum and Aspergillus niger preserved at 4 °C in PDA slant mediums, they were inoculated on the sterilized PDA slant mediums. Then, they were placed for 7 days at 25 °C in an incubator (MJ-150-II mold incubator, Shanghai Yiheng Scientific Instrument Co., Shanghai, China) for cultivation, and when the surface was covered with fungi, the surface was rinsed with sterile water, in order to wash down the spores present on the surface of the colony. Sterile 4-layer gauzes were used to remove impurities and to make spore suspensions, and a microplate reader (Multiskan FC, Thermo Scientific, Waltham, MA, USA) was used to measure the initial value of OD 600. The initial value obtained was 0.10–0.15.
Sterilized anhydrous soil was used as the substrate, and the treatment methods of the substrate were as follows: Soil was sterilized in a pressure steam sterilizer, whose pressure was 103 kPa, temperature was 121 °C, and sterilization time was 20 min, and the sterilization was performed 3 times. The treatment method used during the sterilization interval was exposure to sunlight for 6 h. After the sterilization procedures were completed, aseptic operation was used to dry the soil at 110 °C for 4 h until it was completely dry. Then, 100 g of the above-mentioned substrate was added to a PE material container, and the upper surface of the substrate was 14.5 cm × 9.0 cm and its thickness was 0.7 cm. Furthermore, 50 g of sterilized PDB medium was added to make the soil water content saturated. At this stage, the PDB medium and the soil constituted the matrixes, and both of them together were the mock-up samples.
Two sets of experiments were performed. A 1 mL volume of the above-mentioned two fungi spore suspensions was inoculated into the center of the surface of the mock-up sample matrixes. The inoculated areas were squares of 10 mm × 10 mm. Menthol was applied to the surface of the matrixes to completely separate the matrixes from the external environment, especially the parts where spore suspensions were inoculated. The application method was pressure spraying, and the applied mass was 1 g. The blank group represents the normal growth of fungi. Similarly, 1 mL of the spore suspensions were inoculated on the surface of the sample matrixes of the mock-ups, and the inoculated areas were squares of 10 mm × 10 mm.
In the second set of experiments, 0.5 mL of spore suspensions were inoculated into Petri dishes, with 40 mm diameter, containing 5 mL of sterilized PDA media, and incubated at 25 °C for 7 days. And then, menthol was applied to the surface.
The samples of the two sets of experiments were placed in an incubator at 25 °C and 90% RH. Samples were collected every day to compare the growths of the fungi. All fungi-covered area data were reported as averages of 3 parallel experiments.

2.2.3. On-Site Antifungal Evaluation

M4001 is located in the north of Xi’an Xianyang International Airport, Shaanxi Province (108.76400471° E, 34.45981979° N, 498.22 m). M4001 has a huge, sealed mound for the mural tomb of the Tang Dynasty, which is of great importance. The two walls of the tomb road were beautifully painted, and the tomb road sloped for multiple courtyards. However, due to high humidity around the tomb (outdoor: 34.7 °C, 40.9% RH; tomb entrance: 32.6 °C, 47.4% RH; tomb bottom: 24 °C, 80% RH), mold breeding was a serious issue during excavation. White area in Figure 1 was covered with mold. Menthol was applied for on-site antifungal evaluation.
Soil sample was collected for mold DNA library construction and sequencing. The library preparations and DNA sequencing were conducted using the MiSeq Illumina platform at Major Biotechnology Company (Shanghai, China). The primer pair barcode-SSU0817F (5′-TTAGCATGGAATAATRRAATAGGA-3′) and 1196R (5′-TCTGGACCTGGTGAGTTTCC-3′) were used to amplify the V5-V7 region of fungal 18S rDNA (PCR instrument: GeneAmp®, 9700, Applied Biosystem, Foster City, CA, USA). The PCR reaction was carried out in a 20 μL system with 10 ng template DNA, and the reaction program was as follows: pre-denaturation at 95 °C for 3 min, then denaturation at 95 °C for 30 s, annealing at 55 °C for 30 s, and extension at 72 °C for 45 s, for a total of 36 cycles, and finally, extension at 72 °C for 10 min. QIIME was used to analyze the sequence data and to form operational taxonomic units (OTUs).
In Figure 1, four spots marked 1 to 4 were used for on-site antifungal evaluation. Spot 1: no treatment; spot 2: menthol applied; spot 3: mold removed mechanically; and spot 4: menthol applied after mechanical mold removal. Observations were recorded on days 1, 3, 5, and 7.

3. Results and Discussions

3.1. Environmental Barrier Evaluation

Many cultural relics are buried underground, which is often considered to be oxygen poor, dark, and damp (high water content). Once cultural relics are excavated, their environment changes quickly to oxygen rich, light abundant (especially in terms of ultraviolet radiation), and less damp. The original physical and chemical equilibration, which was maintained for hundreds of years, is broken. The relics face the immediate risks of oxidation, photoreaction, and water loss. Currently, no materials or techniques exist that can effectively protect excavated relics from damages due to severe environmental changes. Current common practices applied during excavation such as plastic film covering or water spraying are more like a matter of expediency. Emergency conservation during excavation requires more scientific, systematic, applicable, and integrated techniques. Volatile binding media (VBMs) [29,30], such as cyclododecane and L-menthol, have been well accepted in archaeological excavations. Their easy removal via sublimation attracts our attention to see whether they can form dense coating to protect excavated relics from sudden environmental changes.
Commercial oxygen indicators, which are widely used in the food industry, are used to investigate the ability of menthol coating to block oxygen contact. The oxygen indicator appears pink when environmental oxygen fraction is less than 0.1% and blue when environmental oxygen fraction is greater than 0.5%. As shown in Figure 2, the oxygen indicator exposed to air is quickly oxidized and appears blue. On the other hand, when the oxygen indicator is sealed with menthol, it still appears pink even after a 720 h exposure to air. The results show that the menthol coating has an excellent ability to block oxygen from contacting menthol-coated objects.
Menthol coatings also show an excellent ability to block water vapor or liquid water from menthol-coated objects. The results are shown in Figure 3. Water is added into two tubes. One tube is sealed with menthol (~5 mm in thickness), while the other is open to air, as illustrated in the inset of Figure 3a. In the tube with no seal, water evaporates almost linearly as expected. In the menthol-sealed tube, it can be clearly seen that there is almost no water loss in 30 days. This shows that menthol coating has an excellent ability to block water vapor exchange with outer environment. The results in Figure 3b tell a slightly different story. In Figure 3b, pH test paper is used as liquid water indicator (significant color changes for better visualization). It is obvious that menthol coating can effectively block liquid water entering the menthol-coated objects. Although not perfect, menthol coating also shows a decent ability to block light, especially radiation below 300 nm, as shown in Figure 3c. OM picture in Figure 3d shows menthol coating consists of stacked needle-like crystals, some of which are fractured or interlaced. The stacked crystals form a dense film that blocks other molecules such as water or oxygen from passing through the film.

3.2. Antifungal Evaluation of Menthol Coatings on Mock-Up Samples

Fungus is another obvious threat to excavated relics during excavation. It is known that many essential oils can be used as biocides [23]. Menthol is a naturally occurring cyclic monoterpene alcohol existing in many plants, which may also have an antifungal ability. Penicillium and Aspergillus are common fungi species [31,32,33] and are often observed in archaeological excavations [34,35]. Thus, they were chosen to explore the antifungal evaluation of menthol coating on mock-ups in laboratory. Sterilized soil as a mock-up sample is used to replace the commonly used agar medium to mimic the real cases of excavation sites. Experiments are designed to perform on two sets of samples: pristine mock-ups and infected mock-ups.
As shown in Figure 4a, in a 10-day period, both Penicillium polonicum and Aspergillus niger in the pristine mock-up group experience the processes of spore germination and hyphae growth in the absence of menthol. On day 3, an obvious amounts of fungi are produced. Within 8 days, the area covered by fungi gradually increased, and remained basically stable afterwards. The growths of these two fungi in the absence of menthol show typical S-shaped growth curves. In Figure 4a, on the same types of samples, upon menthol application, no fungal growth is observed. The infected area is zero for both fungi.
In Figure 4b, the mock-ups are infected by fungi beforehand with approximately 20% infection area coverage. For both Penicillium polonicum and Aspergillus niger, the processes of spore propagation and hypha growth are observed in the absence of menthol, while the fungi growth is prohibited in the presence of menthol similar to the results in Figure 4a. It appears that menthol can prevent the growth of external fungi and can also prevent the growth of already infected fungi.
Essential oils (EOs), such as phenols, flavonoids, alkaloids, coumarins, and tannins, have also been examined as biocides in heritage conservation [23,24,25]. However, many of them are fairly reactive, corrosive (for example, phenols), toxic, or carcinogenic, which make them bad choices for antifungal applications in heritage conservation. Menthol has a decent antifungal ability, slightly less efficient than many other EO, such as eugenol and thymol [23]. But menthol is not reactive under the conditions in which heritage sites normally exist and is safe to use by conservators. In this study, menthol, much less expensive than most EOs, can be applied in the form of multiple coatings to improve its antifungal ability (due to a higher concentration) and can provide other conservation functions.

3.3. On-Site Antifungal Evaluations of Menthol Coatings

On-site antifungal evaluations were carried out in a tomb of the Tang Dynasty named M4001 during its archaeological excavation. Due to high humidity, mold breeding was a serious issue throughout the excavation process. Before applying any antifungal treatment, a soil sample was collected for mold DNA library construction and sequencing to understand the existing fungi species.
Illumina sequencing on the soil was performed, processing and quality control were carried out according to optimization standards, chimeras and sequences outside the target sequences were removed, and a total of 34,285 high-quality gene sequences were obtained. The shortest sequence length was 189 bp, while the longest sequence length was 323 bp, and the average sequence length was 217 bp. The optimized sequence was used to evaluate the microbial abundance and diversity of soil samples from the cultural relic site.
The 34,285 effective sequences of fungi were divided into 27 OTUs, indicating that the types of fungi in the cultural relics are relatively monotonous. The fungal diversity indexes of the sample collected at tomb M4001 are shown in Table 1. The coverage index represents the degree of coverage of the sample’s microbial population obtained by sequencing. When the coverage index reaches 100%, it means that the sequencing can cover all the microbial populations present in the sample. The coverage index in Table 1 is very close to one, indicating that the sequencing results can basically represent the real condition of the sample. Community diversity is usually expressed by Chao1 index, Ace index, Shannon index, and Simpson index. Chao1 index and Ace index are used to indicate the richness of samples, while Shannon index and Simpson index are used to indicate the diversity of samples. Generally speaking, the larger the value of indexes, the higher the diversity of the community. It seems that there are fewer types of fungi in M4001, which may ease the antifungal management in this area.
Fungal community structure data of tomb M4001 show that the fungi basically belong to the Ascomycota, accounting for more than 99.9%. As shown in Figure 5a, at the family level, the Nectriaceae family has an absolute advantage, accounting for 93.05%, which is consistent with the low diversity reflected by the fungal diversity indexes. At the genus level, only five genera are richer than 1%, as shown in Figure 5b. Three genera have values >5%, including llyonectria (42.36%), fusicolla (24.72%), and neonectria (23.65%). Other two genera that accounted for more than 1% are Pseudogymnoascus (4.44%) and dactylonectria (1.76%). The richness of another six genera is between 0.1% and 1%, namely, titaea (0.97%), verticillium (0.62%), fusarium (0.45%), plectosphaerella (0.31%), clonostachys (0.27%), and cephalotrichum (0.14%), and the total proportion of other genera is 0.31%. It shows that for this environmental sample, the dominant fungi should be the three genera, llyonectria, fusicolla, and neonectria, of the family of Nectriaceae.
On-site antifungal evaluations were performed on the wall of the tomb entrance where no mural existed. Four spots marked 1 to 4 were used for on-site antifungal evaluation as shown in Figure 1, and actions taken on each spot are described in the experimental section. The changes with time on each spot were recorded by a camera, which are shown in Figure 6. The changes on the 7th day were further examined with a portable microscope. Images are shown in Figure 7. In both figures, it can be seen that menthol can successfully inhibit the germination and growth of molds. Furthermore, the performed experiments also show that menthol can be completely removed after air exposure in about 4–6 weeks as expected.

4. Conclusions

In this study, the possibility of menthol coatings as a reversible environmental barrier to protect cultural relics during excavation is examined. Laboratory results show that the menthol coating has an excellent ability to block oxygen and water molecules from passing through it; thus, it can stop various fungal growths and cut off radiation below 300 nm. Comparing with other essential oils (EOs), such as phenols, flavonoids, alkaloids, coumarins, tannins, etc., menthol is much less reactive (safe for heritage sites), much less expensive, and safe for use by conservators and to the environment. Menthol is applied in the form of coatings, which improves its antifungal ability (due to a higher concentration) and provides other conservation functions.
On-site antifungal applications on a mural tomb of the Tang Dynasty, located in the north of Xi’an Xianyang International Airport, provided satisfactory results. Laboratory and field experiments show that menthol coating has highly potential for being used in the comprehensive emergency protection of relics against sudden environmental changes during excavation. Meanwhile, its sublime nature guarantees that menthol can be completely and easily removed after an excavation, indicating that menthol coatings are completely reversible.

Author Contributions

Conceptualization, X.H. and H.L.; methodology, W.Z., K.S. and X.C.; validation, W.Z., K.S. and Y.Z.; resources, X.C., Y.Z. and X.Z.; writing—original draft preparation, W.Z.; writing—review and ed-iting, X.H. and H.L.; supervision, X.H.; project administration, H.L. and X.Z.; funding acquisition, X.H. and H.L. All authors have read and agreed to the published version of the manuscript.

Funding

The authors are grateful to the financial supports obtained from the National Key R&D Program of China (No. 2019YFC1520104), Key Program of National Natural Science Foundation of China (No. 51732008), and the National Natural Science Foundation of China (No. 52172297).

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the study reported in this paper.

References

  1. Pires, F.; Bilotta, E.; Flora, A.; Lourenço, P.B. Assessment of Excavated Tunnels Stability in the Maya Archeological Area of Copán, Honduras. Int. J. Archit. Herit. 2023, 17, 431–449. [Google Scholar] [CrossRef]
  2. Musumeci, R.E.; Foti, E.; Li Rosi, D.; Sanfilippo, M.; Stancanelli, L.M.; Iuppa, C.; Sapienza, V.; Yang, W.; Cantarero, M.; Patanè, D. Debris-flow hazard assessment at the archaeological UNESCO world heritage site of Villa Romana del Casale (Sicily, Italy). Int. J. Disaster Risk Reduct. 2021, 64, 102509. [Google Scholar] [CrossRef]
  3. Stanaszek-Tomal, E. Environmental Factors Causing the Development of Microorganisms on the Surfaces of National Cultural Monuments Made of Mineral Building Materials—Review. Coatings 2020, 10, 1203. [Google Scholar] [CrossRef]
  4. Xu, J.; Wei, Y.; Jia, H.; Xiao, L.; Gong, D. A new perspective on studying burial environment before archaeological excavation: Analyzing bacterial community distribution by high-throughput sequencing. Sci. Rep. 2017, 7, 41691. [Google Scholar] [CrossRef] [PubMed]
  5. Chen, X.-Q.; Xia, K.; Hu, W.; Cao, M.; Deng, K.; Fang, S. Extraction of underwater fragile artifacts: Research status and prospect. Herit. Sci. 2022, 10, 9. [Google Scholar] [CrossRef]
  6. Zhang, J.; Cai, L.; Gao, X.; Liu, M. Thought and suggestion on protection techniques of paint layers of Qin Terracotta Army. Sci. Conserv. Archaeol. 2007, 19, 51–56. (In Chinese) [Google Scholar]
  7. Selwyn, L.S.; Sirois, P.I.; Argyropoulos, V. The corrosion of excavated archaeological iron with details on weeping and akaganéite. Stud. Conserv. 2013, 44, 217–232. [Google Scholar]
  8. Réguer, S.; Neff, D.; Bellot-Gurlet, L.; Dillmann, P. Deterioration of iron archaeological artefacts: Micro-Raman investigation on Cl-containing corrosion products. J. Raman Spectrosc. 2007, 38, 389–397. [Google Scholar] [CrossRef]
  9. Réguer, S.; Dillmann, P.; Mirambet, F. Buried iron archaeological artefacts: Corrosion mechanisms related to the presence of Cl-containing phases. Corros. Sci. 2007, 49, 2726–2744. [Google Scholar] [CrossRef]
  10. Marcaida, I.; Maguregui, M.; Morillas, H.; Prieto-Taboada, N.; de Vallejuelo, S.F.-O.; Veneranda, M.; Madariaga, J.M.; Martellone, A.; De Nigris, B.; Osanna, M. In situ non-invasive characterization of the composition of Pompeian pigments preserved in their original bowls. Microchem. J. 2018, 139, 458–466. [Google Scholar] [CrossRef]
  11. Albelda Berenguer, M.; Monachon, M.; Jacquet, C.; Junier, P.; Rémazeilles, C.; Schofield, E.J.; Joseph, E. Biological oxidation of sulfur compounds in artificially degraded wood. Int. Biodeterior. Biodegrad. 2019, 141, 62–70. [Google Scholar] [CrossRef]
  12. Okpalanozie, O.E.; Adebusoye, S.A.; Troiano, F.; Cattò, C.; Ilori, M.O.; Cappitelli, F. Assessment of indoor air environment of a Nigerian museum library and its biodeteriorated books using culture-dependent and –independent techniques. Int. Biodeterior. Biodegrad. 2018, 132, 139–149. [Google Scholar] [CrossRef]
  13. Nava, S.; Becherini, F.; Bernardi, A.; Bonazza, A.; Chiari, M.; Garcia-Orellana, I.; Lucarelli, F.; Ludwig, N.; Migliori, A.; Sabbioni, C.; et al. An integrated approach to assess air pollution threats to cultural heritage in a semi-confined environment: The case study of Michelozzo’s Courtyard in Florence (Italy). Sci. Total Environ. 2010, 408, 1403–1413. [Google Scholar] [CrossRef] [PubMed]
  14. Borrego, S.; Molina, A. Fungal assessment on storerooms indoor environment in the National Museum of Fine Arts, Cuba. Air Qual. Atmos. Health 2019, 12, 1373–1385. [Google Scholar] [CrossRef]
  15. Sabatini, L.; Sisti, M.; Campana, R. Evaluation of fungal community involved in the bioderioration process of wooden artworks and canvases in Montefeltro area (Marche, Italy). Microbiol. Res. 2018, 207, 203–210. [Google Scholar] [CrossRef] [PubMed]
  16. Rosado, T.; Mirao, J.; Candeias, A.; Caldeira, A.T. Microbial communities analysis assessed by pyrosequencing--a new approach applied to conservation state studies of mural paintings. Anal. Bioanal. Chem. 2014, 406, 887–895. [Google Scholar] [CrossRef] [PubMed]
  17. Rosado, T.; Gil, M.; Caldeira, A.T.; Martins, M.d.R.; Dias, C.B.; Carvalho, L.; Mirão, J.; Candeias, A.E. Material Characterization and Biodegradation Assessment of Mural Paintings: Renaissance Frescoes from Santo Aleixo Church, Southern Portugal. Int. J. Archit. Herit. 2014, 8, 835–852. [Google Scholar] [CrossRef]
  18. Liu, W.; Zhou, X.; Jin, T.; Li, Y.; Wu, B.; Yu, D.; Yu, Z.; Su, B.; Chen, R.; Feng, Y.; et al. Multikingdom interactions govern the microbiome in subterranean cultural heritage sites. Proc. Natl. Acad. Sci. USA 2022, 119, e2121141119. [Google Scholar] [CrossRef] [PubMed]
  19. Valantinavicius, M.; Micallef, D.; Cassar, J.; Caruana, J.; Ciantelli, C. Sheltering megalithic Temples in Malta—Evaluating the process through data collection and modelling. In IOP Conference Series: Materials Science and Engineering; IOP Publishing: Bristol, UK, 2020; Volume 949, p. 012035. [Google Scholar]
  20. Barresi, G.; Di Carlo, E.; Trapani, M.R.; Parisi, M.G.; Chille, C.; Mule, M.F.; Cammarata, M.; Palla, F. Marine organisms as source of bioactive molecules applied in restoration projects. Herit. Sci. 2015, 3, 17. [Google Scholar] [CrossRef]
  21. Magaudda, G. The recovery of biodeteriorated books and archive documents through gamma radiation: Some considerations on the results achieved. J. Cult. Herit. 2004, 5, 113–118. [Google Scholar] [CrossRef]
  22. Da Silva, M.; Moraes, A.M.L.; Nishikawa, M.M.; Gatti, M.J.A.; Vallim de Alencar, M.A.; Brandão, L.E.; Nóbrega, A. Inactivation of fungi from deteriorated paper materials by radiation. Int. Biodeterior. Biodegrad. 2006, 57, 163–167. [Google Scholar] [CrossRef]
  23. Veneranda, M.; Blanco-Zubiaguirre, L.; Roselli, G.; Di Girolami, G.; Castro, K.; Madariaga, J.M. Evaluating the exploitability of several essential oils constituents as a novel biological treatment against cultural heritage biocolonization. Microchem. J. 2018, 138, 1–6. [Google Scholar] [CrossRef]
  24. Palla, F.; Bruno, M.; Mercurio, F.; Tantillo, A.; Rotolo, V. Essential Oils as Natural Biocides in Conservation of Cultural Heritage. Molecules 2020, 25, 730. [Google Scholar] [CrossRef] [PubMed]
  25. Li, T.; Hu, Y.; Zhang, B. Evaluation of efficiency of six biocides against microorganisms commonly found on Feilaifeng Limestone, China. J. Cult. Herit. 2020, 43, 45–50. [Google Scholar] [CrossRef]
  26. Soottitantawat, A.; Takayama, K.; Okamura, K.; Muranaka, D.; Yoshii, H.; Furuta, T.; Ohkawara, M.; Linko, P. Microencapsulation of l-menthol by spray drying and its release characteristics. Innov. Food Sci. Emerg. Technol. 2005, 6, 163–170. [Google Scholar] [CrossRef]
  27. Han, X.; Rong, B.; Huang, X.; Zhou, T.; Luo, H.; Wang, C. The Use of Menthol as Temporary Consolidant in the Excavation of Qin Shihuang’s Terracotta Army. Archaeometry 2014, 56, 1041–1053. [Google Scholar] [CrossRef]
  28. Han, X.; Huang, X.; Zhang, B. Morphological studies of menthol as a temporary consolidant for urgent conservation in archaeological field. J. Cult. Herit. 2016, 18, 271–278. [Google Scholar] [CrossRef]
  29. Rowe, R. Second Fiddle: A Review of Lesser-Known Volatile Binding Media in Conservation; Apollo—University of Cambridge Repository: Cambridge, UK, 2018. [Google Scholar] [CrossRef]
  30. Rozeik, C. Volatile Binding Media: The First 20 Years … and Beyond; Apollo—University of Cambridge Repository: Cambridge, UK, 2018. [Google Scholar] [CrossRef]
  31. Skóra, J.; Sulyok, M.; Nowak, A.; Otlewska, A.; Gutarowska, B. Toxinogenicity and cytotoxicity of Alternaria, Aspergillus and Penicillium moulds isolated from working environments. Int. J. Environ. Sci. Technol. 2016, 14, 595–608. [Google Scholar] [CrossRef]
  32. Ma, Y.; Ling, T.J.; Su, X.Q.; Jiang, B.; Nian, B.; Chen, L.J.; Liu, M.-L.; Zhang, Z.-Y.; Wang, D.-P.; Mu, Y.-Y.; et al. Integrated proteomics and metabolomics analysis of tea leaves fermented by Aspergillus niger, Aspergillus tamarii and Aspergillus fumigatus. Food Chem. 2021, 334, 127560. [Google Scholar] [CrossRef]
  33. Fouda, A.; Abdel-Maksoud, G.; Abdel-Rahman, M.A.; Eid, A.M.; Barghoth, M.G.; El-Sadany, M.A.-H. Monitoring the effect of biosynthesized nanoparticles against biodeterioration of cellulose-based materials by Aspergillus niger. Cellulose 2019, 26, 6583–6597. [Google Scholar] [CrossRef]
  34. Ma, W.; Wu, F.; Tian, T.; He, D.; Zhang, Q.; Gu, J.-D.; Duan, Y.; Ma, D.; Wang, W.; Feng, H. Fungal diversity and its contribution to the biodeterioration of mural paintings in two 1700-year-old tombs of China. Int. Biodeterior. Biodegrad. 2020, 152, 104972. [Google Scholar] [CrossRef]
  35. Favero-Longo, S.E.; Brigadeci, F.; Segimiro, A.; Voyron, S.; Cardinali, M.; Girlanda, M.; Piervittori, R. Biocide efficacy and consolidant effect on the mycoflora of historical stuccos in indoor environment. J. Cult. Herit. 2018, 34, 33–42. [Google Scholar] [CrossRef]
Coatings 13 02047 g001
Figure 1. M4001 in the north of Xi’an Xianyang International Airport, Shaanxi Province; white area was covered with mold. The spots marked 1–4 are the places where experiments were performed later.
Figure 1. M4001 in the north of Xi’an Xianyang International Airport, Shaanxi Province; white area was covered with mold. The spots marked 1–4 are the places where experiments were performed later.
Coatings 13 02047 g001
Coatings 13 02047 g002
Figure 2. Photography results of the color change of oxygen indicators (pink: not oxidized; blue: oxidized).
Figure 2. Photography results of the color change of oxygen indicators (pink: not oxidized; blue: oxidized).
Coatings 13 02047 g002
Coatings 13 02047 g003
Figure 3. (a) Water evaporation data versus time in the presence and absence of menthol seal, inset: schematic illustration of experimental setup; (b) photography results of water blocking experiment; (c) UV-Vis spectrum of menthol coating on quartz (~0.5 mm in thickness); and (d) OM picture of menthol coating on glass slide that was taken with a Leica DM2700P microscope.
Figure 3. (a) Water evaporation data versus time in the presence and absence of menthol seal, inset: schematic illustration of experimental setup; (b) photography results of water blocking experiment; (c) UV-Vis spectrum of menthol coating on quartz (~0.5 mm in thickness); and (d) OM picture of menthol coating on glass slide that was taken with a Leica DM2700P microscope.
Coatings 13 02047 g003
Coatings 13 02047 g004
Figure 4. The growth of Aspergillus niger and Penicillium polonicum on (a) original mock-ups and (b) infected mock-ups
Figure 4. The growth of Aspergillus niger and Penicillium polonicum on (a) original mock-ups and (b) infected mock-ups
Coatings 13 02047 g004
Coatings 13 02047 g005
Figure 5. Community analyses pie plots at (a) the family level and (b) the genus level of the soil sample from tomb M4001.
Figure 5. Community analyses pie plots at (a) the family level and (b) the genus level of the soil sample from tomb M4001.
Coatings 13 02047 g005
Coatings 13 02047 g006
Figure 6. The dynamic effects of on-site antifungal evaluations of menthol: (a) day 1; (b) day 3; (c) day 5; and (d) day 7 (1: no treatment; 2: menthol applied; 3: mold removed mechanically; and 4: menthol applied after mechanical mold removal).
Figure 6. The dynamic effects of on-site antifungal evaluations of menthol: (a) day 1; (b) day 3; (c) day 5; and (d) day 7 (1: no treatment; 2: menthol applied; 3: mold removed mechanically; and 4: menthol applied after mechanical mold removal).
Coatings 13 02047 g006
Coatings 13 02047 g007
Figure 7. The microscopic images of the effects of on-site antifungal evaluations: (a) no treatment; (b) menthol applied; (c) mold removed mechanically; and (d) menthol applied after mechanical mold removal; pictures were taken on a portable AF4115ZT microscope from AnMo Electronic, Taiwan.
Figure 7. The microscopic images of the effects of on-site antifungal evaluations: (a) no treatment; (b) menthol applied; (c) mold removed mechanically; and (d) menthol applied after mechanical mold removal; pictures were taken on a portable AF4115ZT microscope from AnMo Electronic, Taiwan.
Coatings 13 02047 g007
Table 1. Fungal diversity indexes of the soil sample from tomb M4001.
Table 1. Fungal diversity indexes of the soil sample from tomb M4001.
Sample EstimatorsAce IndexChao1 IndexCoverageShannon IndexSimpson Index
-29.558300.99991.5900.272
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zhang, W.; Shen, K.; Zhang, Y.; Chen, X.; Zhao, X.; Huang, X.; Luo, H. Reversible Organic Coatings for On-Site Comprehensive Emergency Protection during Archaeological Excavations. Coatings 2023, 13, 2047. https://doi.org/10.3390/coatings13122047

AMA Style

Zhang W, Shen K, Zhang Y, Chen X, Zhao X, Huang X, Luo H. Reversible Organic Coatings for On-Site Comprehensive Emergency Protection during Archaeological Excavations. Coatings. 2023; 13(12):2047. https://doi.org/10.3390/coatings13122047

Chicago/Turabian Style

Zhang, Wenjin, Kejin Shen, Yaxu Zhang, Xueping Chen, Xichen Zhao, Xiao Huang, and Hongjie Luo. 2023. "Reversible Organic Coatings for On-Site Comprehensive Emergency Protection during Archaeological Excavations" Coatings 13, no. 12: 2047. https://doi.org/10.3390/coatings13122047

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop