Cuvillier Luana, Passaretti Arianna, Guilminot Elodie, Joseph Edith
Laboratory of Technologies for Heritage Materials, University of Neuchâtel, Bellevaux 51, 2000 Neuchâtel, Switzerland.
Haute Ecole Arc Conservation Restauration, University of Applied Sciences and Arts Western Switzerland HES-SO, Espace de l'Europe 11, 2000 Neuchâtel, Switzerland.
Gels. 2024 Jan 11;10(1):55. doi: 10.3390/gels10010055.
In the field of cultural heritage, the use of natural gels is rising for the application of active agents. Here, two natural polymers are assessed: agar, a pioneer hydrogel for conservation treatments, and chitosan, a rather novel and metal-binding gel. For chitosan, a state-of-the-art based formulation (CS-ItA-LCys) is evaluated as it was reported for silver-complexing properties. It is evaluated whether these polymers can withstand the addition of the chelating compound deferoxamine, which is a bacterial siderophore. This allows for the obtainment of completely bio-sourced gel systems. A Fourier-transformed (FT) infrared spectroscopy characterization is performed, completed with rheological measurements and Cryo-Scanning Electron Microscopy (cryo-SEM) to investigate the physico-chemical properties of the gels, as well as their interaction with deferoxamine. Both polymers are also tested for their inherent complexing ability on silver ions using FT-Raman spectroscopy. A multi-analytical comparison shows different microstructures, in particular, the presence of a thick membrane for chitosan and different mechanical behaviors, with agar being more brittle. Neither hydrogel seems affected by the addition of deferoxamine; this is shown by similar rheological behavior and molecular structures in the presence or absence of the chelator. The intrinsic abilities of the chitosan formulation to make silver complex are demonstrated with the observation of two peaks characteristic of Ag-S and Ag-O bonds. Agar and chitosan are both proven to be reliable gels to act as carriers for bio-based active agents. This paper confirms the potential asset of the chitosan formulation CS-ItA-LCys as a promising gel for the complexation of soluble silver.
在文化遗产领域，天然凝胶在活性剂应用方面的使用正在增加。在此，对两种天然聚合物进行评估：琼脂，一种用于保护处理的先驱水凝胶；以及壳聚糖，一种相当新颖的金属结合凝胶。对于壳聚糖，评估了一种基于现有技术的配方（CS-ItA-LCys），因为有报道称其具有银络合特性。评估了这些聚合物是否能承受螯合化合物去铁胺（一种细菌铁载体）的添加。这使得能够获得完全生物源的凝胶体系。进行了傅里叶变换（FT）红外光谱表征，并辅以流变学测量和低温扫描电子显微镜（cryo-SEM），以研究凝胶的物理化学性质及其与去铁胺的相互作用。还使用FT-拉曼光谱测试了这两种聚合物对银离子的固有络合能力。多分析比较显示出不同的微观结构，特别是壳聚糖存在厚膜以及不同的力学行为，琼脂更脆。两种水凝胶似乎都不受去铁胺添加的影响；这通过在有或没有螯合剂的情况下相似的流变行为和分子结构得以证明。通过观察Ag-S和Ag-O键的两个特征峰，证明了壳聚糖配方形成银络合物的内在能力。琼脂和壳聚糖都被证明是可靠的凝胶，可作为生物基活性剂的载体。本文证实了壳聚糖配方CS-ItA-LCys作为一种有前景的可溶性银络合凝胶的潜在价值。
