table3_In Vitro Evaluation of MgB2 Powders as Novel Tools to Fight Fungal Biodeterioration of Heritage Buildings and Objects.docx

The 17th–19th century wooden and stone churches are an iconic symbol for the Romanian national heritage, raising urgent needs for the development of efficient and ecofriendly restoration and preservation solutions. Nanotechnology has a great but largely unexplored potential in this field, providing new tools and methods to achieve higher consolidation and protection efficiency, mainly due to the ability of nanoparticles to inhibit the growth and metabolic activity of different biodeteriorating agents, including fungi. The purpose of the present study was to report for the first time on the efficiency of MgB2 materials, mainly prized for their practical superconducting properties, against a large collection of filamentous fungal strains recently isolated from biodeteriorated wooden and stone heritage objects. Four types of MgB2 powders, with a crystallite size of 42–113 nm, were tested by qualitative (on 149 strains) and quantitative (on 87 strains) assays. The cytotoxicity was evaluated by the microscopic analysis of SiHa cells morphology and Hep2 cell cycle analysis and the ecotoxicity by the Allium test. The tested filamentous fungal strains belonged to 11 different genera, and those isolated from mural paintings and wooden objects exhibited the best capacity to colonize the inert substratum. All MgB2 powders exhibited similar and relatively low minimal inhibitory concentrations (MIC) values against the Aspergillus and Penicillium isolates, which were predominated among isolates. From the tested powders, PVZ and CERAC proved to be more efficient against the strains isolated from stone and wood materials, while LTS was active against the fungal strains colonizing the mural paintings and museum objects. The cytotoxicity results indicated that the tested powders are toxic for the human cells at concentrations higher than 50 µg/ml, but, however, the very short lifetime of these NPs prevents their accumulation in the natural environment and, thus, the occurrence of toxic effects. The tested powders proved to be ecofriendly at the active antifungal concentrations, as suggested by the phytotoxicity test results. Taken together, our results suggest the potential of the MgB2 materials for the development of environmentally safe antifungal substances, which can be used in the control of the material cultural heritage biodeterioration process.

17至19世纪的木质与石质教堂是罗马尼亚民族遗产的标志性象征，因此亟需开发高效且环保的修复与保护方案。纳米技术在该领域具备巨大但尚未充分探索的潜力，可为实现更高水平的加固与防护效能提供全新工具与方法，其核心优势在于纳米颗粒能够抑制包括真菌在内的各类生物劣化介质的生长与代谢活动。本研究首次报告了二硼化镁（MgB₂）材料——这类材料原本以其实用的超导性能广受赞誉——针对近期从生物劣化的木质与石质文化遗产载体中分离得到的大量丝状真菌菌株的抑菌效能。本研究共测试了四种晶粒尺寸介于42至113纳米的MgB₂粉末，分别通过定性实验（覆盖149株菌株）与定量实验（覆盖87株菌株）进行评估。细胞毒性通过SiHa细胞的形态学显微分析以及Hep2细胞周期分析进行检测，生态毒性则采用洋葱（Allium）试验开展评估。受试丝状真菌菌株隶属于11个不同属，其中从壁画与木质文物中分离得到的菌株对惰性基质的定殖能力最强。所有受试的MgB₂粉末对曲霉菌（Aspergillus）与青霉菌（Penicillium）分离株均展现出相似且相对较低的最低抑菌浓度（Minimal Inhibitory Concentration, MIC）值，这两类菌株在分离株中占比最高。在受试粉末中，PVZ与CERAC对从石质与木质文物中分离得到的菌株展现出更优的抑菌效果，而LTS则对定殖于壁画与馆藏文物的真菌菌株具有抑菌活性。细胞毒性实验结果显示，当浓度高于50微克/毫升时，受试粉末对人体细胞具有毒性，但此类纳米颗粒的极短自然存留周期可阻止其在自然环境中累积，故而不会引发毒性反应。植物毒性实验结果表明，在有效抑菌浓度下，受试粉末具备环境友好性。综上，本研究结果表明，MgB₂材料具备开发环境友好型抗真菌制剂的潜力，可用于管控文物材质的生物劣化过程。