Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India.
Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.
Int J Biol Macromol. 2021 Nov 1;190:56-60. doi: 10.1016/j.ijbiomac.2021.08.204. Epub 2021 Sep 1.
Small molecules ranging from organic to inorganic systems have been reported as stabilizing agents for collagen. Various transition metal complexes have been utilized as tanning agent. However, as per the environmental norms issued by various regulatory agencies, the presence of certain metals such as Cr, Fe, Al, Zr and Ti in leather has been restricted to minimal amount (50 ppm), an unsurmountable task. To overcome the above issue and find an alternative tanning system, here in this study, we have reported the interaction of two water-soluble zinc-based metal-organic frameworks (MOFs), i.e., ZnPV (1) and ZnPA (2), with collagen using various spectroscopic techniques. Fibrillation kinetics studies showed that a significant delay in fibril formation with Zn-MOFs treated collagen was observed compared to the collagen untreated/ treated with individual ligands and metal salt. Circular dichroism studies show that at a low weight ratio (1:0.2 and 1:1::Collagen: MOF), no perturbation in the triple helical structure was observed, while at higher weight ratio (1:4), denaturation of collagen occurs. FT-IR studies showed that no perturbation was observed in the amide backbone in MOF-treated collagen. Differential scanning calorimetric data revealed that both Zn-MOFs increased the thermal denaturation temperature by 22 ± 2 °C compared to the collagen treated with individual entities. The viscosity of collagen rises with the increase in the concentration of Zn-MOFs. To the best of our knowledge, this is the first report on the use of the metal-organic framework as a stabilizing agent for collagen structure and might help in exploring the MOFs as potential tanning agents.
已报道小分子（包括有机和无机体系）可作为胶原蛋白的稳定剂。各种过渡金属配合物已被用作鞣剂。然而，根据各种监管机构发布的环境规范，皮革中某些金属（如 Cr、Fe、Al、Zr 和 Ti）的存在量已被限制在最小量（50ppm），这是一项难以完成的任务。为了克服上述问题并寻找替代鞣制系统，在此项研究中，我们报道了两种水溶性锌基金属有机框架（MOFs），即 ZnPV（1）和 ZnPA（2）与胶原蛋白的相互作用，使用了各种光谱技术。原纤维形成动力学研究表明，与未经处理/用单独配体和金属盐处理的胶原蛋白相比，用 Zn-MOF 处理的胶原蛋白的原纤维形成明显延迟。圆二色性研究表明，在低重量比（1:0.2 和 1:1::胶原蛋白:MOF）下，未观察到三螺旋结构的扰动，而在较高的重量比（1:4）下，胶原蛋白发生变性。傅里叶变换红外光谱研究表明，在 MOF 处理的胶原蛋白中，酰胺骨架未观察到扰动。差示扫描量热法数据表明，与用单个实体处理的胶原蛋白相比，两种 Zn-MOFs 都将热变性温度提高了 22±2°C。胶原蛋白的粘度随 Zn-MOFs 浓度的增加而升高。据我们所知，这是首次报道将金属有机框架用作胶原蛋白结构的稳定剂，并可能有助于探索 MOFs 作为潜在的鞣剂。
