Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Str. 35, 85354 Freising, Germany; Chair of Bioseparation Engineering, School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, 85748 Garching, Germany.
Chair of Bioseparation Engineering, School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, 85748 Garching, Germany; Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 02139 Cambridge, MA, United States; Division of Medicinal Chemistry, Otto Loewi Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria; BioTechMed-Graz, Austria.
J Colloid Interface Sci. 2023 Mar 15;634:418-430. doi: 10.1016/j.jcis.2022.12.035. Epub 2022 Dec 10.
The high binding affinity of iron(oxyhydr)oxides for phosphate has recently been used in medicine to treat hyperphosphatemia, an abnormally elevated phosphate concentration in the blood. For iron(oxyhydr)oxide nanoparticles, the composition of the organic shell has a more significant influence on their interaction with phosphate than is often assumed. This study shows different mechanisms in phosphate binding, using the example of two similar new phosphate-binding agents.
We characterized the phosphate-binding behavior of two iron(oxyhydr)oxide-based nanomaterials with similar composition and particle properties and investigated their binding mechanisms by spectroscopic methods.
For the often prescribed Velphoro, we demonstrated a phosphate binding capacity of>210 mg/g. A similar active ingredient named C-PAM binds over 573 mg/g. Spectroscopic measurements highlighted differences in the binding mechanism. While Velphoro binds phosphate via surface complexation independent of pH and adsorbent concentration, C-PAM shows a strong concentration dependence. At low concentrations, phosphate is bound via complexation reactions. The iron(oxyhydr)oxide structure was dissolved at higher phosphate concentrations and formed various iron phosphate species. The substances behave differently upon interaction with phosphate, although being very similar in composition and crystal structure. Thus, we demonstrated a crucial influence of the ligands in the shell on the binding mechanism.
最近，铁（氧）氢氧化物对磷酸盐的高亲和力已被用于医学治疗高磷酸盐血症，即血液中磷酸盐浓度异常升高。对于铁（氧）氢氧化物纳米粒子，有机壳的组成对其与磷酸盐的相互作用的影响比人们通常认为的要大得多。本研究以两种类似的新型磷酸盐结合剂为例，展示了不同的磷酸盐结合机制。
我们用两种组成和颗粒性质相似的铁（氧）氢氧化物基纳米材料来描述其对磷酸盐的结合行为，并通过光谱方法研究了它们的结合机制。
对于常用的 Velphoro，我们证明其磷酸盐结合能力大于 210 mg/g。一种名为 C-PAM 的类似有效成分可结合超过 573 mg/g 的磷酸盐。光谱测量突出了结合机制的差异。Velphoro 通过与 pH 和吸附剂浓度无关的表面络合来结合磷酸盐，而 C-PAM 则表现出很强的浓度依赖性。在低浓度下，磷酸盐通过络合反应结合。在较高的磷酸盐浓度下，铁（氧）氢氧化物结构溶解并形成各种铁磷酸盐。这些物质在与磷酸盐相互作用时表现出不同的行为，尽管它们在组成和晶体结构上非常相似。因此，我们证明了壳层中的配体对结合机制有重要影响。
