Table_1_Formulation of Mesoporous Silica Nanoparticles for Controlled Release of Antimicrobials for Stone Preventive Conservation.DOCX

The biotic deterioration of artifacts of archaeological and artistic interest mostly relies on the action of microorganisms capable of thriving under the most disparate environmental conditions. Thus, to attenuate biodeterioration phenomena, biocides can be used by the restorers to prevent or slow down the microbial growth. However, several factors such as biocide half-life, its wash-out because of environmental conditions, and its limited time of action make necessary its application repeatedly, leading to negative economic implications. Sound and successful treatments are represented by controlled release systems (CRSs) based on porous materials. Here, we report on the design and development of a CRS system based on mesoporous silica nanoparticles (MSNs), as a carrier, and loaded with a biocide. MSNs, with a diameter of 55 nm and cylindrical pores of ca. 3–8 nm arranged as parallel arrays concerning the NP diameter, and with 422 m2/g of specific surface area were synthesized by the sol-gel method assisted by oil in water emulsion. Biocide loading and release were carried out in water and monitored by UV-Vis Spectroscopy; in addition, microbiological assay was performed using as control the MCM-41 mesoporous silica loaded with the same biocide. The role of specific supramolecular interaction in regulating the release is discussed. Further, we demonstrated that this innovative formulation was useful in inhibiting the in vitro growth of Kocuria rhizophila, an environmental Gram-positive bacterial strain. Besides, the CRS here prepared reduced the bacterial biomass contaminating a real case study (i.e., stone derived from the Santa Margherita cave located in Sicily, Italy), after several months of treatment thus opening for innovative treatments of deteriorated stone artifacts.

具有考古与艺术价值的文物的生物劣变，主要由能够在最迥异的环境条件下存活增殖的微生物活动所介导。为缓解生物劣变现象，修复师可通过施用杀菌剂以预防或减缓微生物的生长。然而，诸如杀菌剂半衰期、环境因素导致的冲刷流失以及作用时长有限等诸多因素，使得重复施用杀菌剂成为必要，进而带来不利的经济影响。基于多孔材料的控释系统（controlled release systems, CRSs）即为行之有效的处理方案。本研究报道了一种以介孔二氧化硅纳米颗粒（mesoporous silica nanoparticles, MSNs）为载体、负载杀菌剂的控释系统的设计与开发流程。该介孔二氧化硅纳米颗粒直径为55 nm，孔径约3~8 nm的圆柱形孔道沿纳米颗粒直径方向呈平行阵列排布，比表面积达422 m²/g，通过水包油乳液辅助溶胶-凝胶法合成。杀菌剂的负载与释放实验均在水环境中开展，并通过紫外-可见光谱法（UV-Vis Spectroscopy）进行监测；此外，本研究以负载相同杀菌剂的MCM-41介孔二氧化硅作为对照，完成了微生物学测定。本文还探讨了特定超分子相互作用对释药过程的调控作用。此外，本研究证实该创新配方可有效抑制体外培养的嗜根考克氏菌（Kocuria rhizophila）——一种环境来源革兰氏阳性菌株——的生长。不仅如此，本研究制备的控释系统在经过数月处理后，可有效减少意大利西西里圣玛格丽塔洞穴石材样本（即实际案例研究对象）上的污染细菌生物量，从而为劣化石质文物的创新修复处理开辟了新的路径。