Chemical Engineering Department (DEQUI), Universidade Federal do Rio Grande do Sul (UFRGS), ZC, 90035-003, Porto Alegre, Brazil.
Chemical Engineering Department (DEQUI), Universidade Federal do Rio Grande do Sul (UFRGS), ZC, 90035-003, Porto Alegre, Brazil.
Mater Sci Eng C Mater Biol Appl. 2020 Feb;107:110215. doi: 10.1016/j.msec.2019.110215. Epub 2019 Oct 31.
Dressings used in burns and chronic wounds treatment must present antimicrobial characteristics. Silver-based compounds are used for a long time as antiseptics, but they present problems related to the release of silver. In order to control the release, Ag ions may be immobilized in supports that must be dispersed in the film used as wound dressing. In this work gelatin-based films using glycerol as plasticizer and incorporated with different concentrations of clinoptilolite zeolite impregnated with silver ions were prepared and characterized, and the potential antimicrobial activity was investigated. For this purpose, films were produced by casting and evaluated in relation to their mechanical, chemical, thermal, morphological and antimicrobial properties, in addition the amount of silver present in the films was quantified and the kinetics of Ag release in vitro was studied. The antimicrobial analysis was done qualitatively, using Escherichia coli and Staphylococcus aureus bacteria and the microorganisms commonly present on human skin collected with a swab, and quantitatively, using Escherichia coli and Staphylococcus aureus. Characterization tests demonstrated that the glycerol concentration of 25% and the zeolite concentration of 0.5% resulted in films with more suitable properties for wound dressing applications and the silver release test showed that the release of the active compound occurs slowly, as expected. All gelatin/clinoptilolite-Ag films showed antibacterial activity against Staphylococcus aureus and human skin bacteria, not presenting expressive differences on the size of the formed halo. Moreover, by the quantitative antimicrobial analisys, it was observed that as the glycerol concentration increases, the antimicrobial action was faster and at the end of the experiment, there were no S. aureus in the solutions where the films were immersed and for the assay with E. coli, the bactericidal activity is slower and probably is needed a higher concentration of silver ions in the sample to completely inhibit the bacteria. However, the bactericidal activity of the gelatin/clinoptilolite-Ag films was satisfactory due its effectiveness in reducing bacterial growth of E. coli and S. aureus. Based on these results the prepared gelatin/clinoptilolite-Ag films could serve as a promising wound dressing with great antibacterial properties, thus possibly helping also the wound healing.
用于烧伤和慢性伤口治疗的敷料必须具有抗菌特性。银基化合物长期以来一直被用作防腐剂，但它们存在与银释放有关的问题。为了控制释放，Ag 离子可以固定在载体中，这些载体必须分散在用作伤口敷料的薄膜中。在这项工作中，使用明胶作为增塑剂，并掺入不同浓度的银离子浸渍的天然沸石制备了含有甘油的薄膜，并对其进行了表征，并研究了其潜在的抗菌活性。为此，通过浇铸制备了薄膜，并对其机械性能、化学性能、热性能、形态和抗菌性能进行了评估，此外还定量了薄膜中存在的银量，并研究了体外 Ag 释放的动力学。抗菌分析采用定性方法，使用大肠杆菌和金黄色葡萄球菌细菌以及用拭子收集的人体皮肤上常见的微生物进行，并用大肠杆菌和金黄色葡萄球菌进行定量分析。特性测试表明，甘油浓度为 25%和沸石浓度为 0.5%，得到的薄膜具有更适合伤口敷料应用的特性，银释放测试表明，活性化合物的释放缓慢，正如预期的那样。所有明胶/天然沸石-Ag 薄膜对金黄色葡萄球菌和人体皮肤细菌均表现出抗菌活性，形成的晕圈大小没有明显差异。此外，通过定量抗菌分析，观察到随着甘油浓度的增加，抗菌作用更快，在实验结束时，浸入薄膜的溶液中没有金黄色葡萄球菌，对于大肠杆菌的测定，杀菌活性较慢，可能需要在样品中加入更高浓度的银离子才能完全抑制细菌。然而，明胶/天然沸石-Ag 薄膜的杀菌活性令人满意，因为它能有效抑制大肠杆菌和金黄色葡萄球菌的生长。基于这些结果，制备的明胶/天然沸石-Ag 薄膜可用作具有良好抗菌性能的有前途的伤口敷料，从而可能还有助于伤口愈合。
