Thapa Dinesh, Westra Steven, Oas Victoria, Kilin Dmitri, Kilina Svetlana
Department of Mathematics and Physics, Thomas More University, Crestview Hills, Kentucky 41017, United States.
Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States.
ACS Omega. 2025 Jan 10;10(3):2539-2552. doi: 10.1021/acsomega.4c06483. eCollection 2025 Jan 28.
This study elucidates the sensitivity of the spin magnetic moment of the Fe-Mg codoped montmorillonite (MMT) nanoclay to its interactions with three unnatural amino acids (AAs): 5-aminovaleric acid, 2-aminopimelic acid, and DL-2-aminocaprylic acid, in the presence and absence of an aqueous environment. These AAs are known as intercalating agents for MMT clay, providing the formation of the nanoplates. Using spin-polarized density functional theory (SP-DFT), the magnetic moment and its tunability to the position of Fe and Mg impurities in the MMT nanoclay crystal lattice, along with the alignment of AA molecules on the nanoclay surface, have been investigated. There is substantial charge transfer between the AA molecule (a donor) and the MMT nanoclay (an acceptor), indicating their strong electrostatic interaction. Moreover, it is found that AA molecules stabilize Fe(II) and prevent its oxidation to Fe(III) through strong interactions with the nanoclay, highlighting the significance of clay-amino acid interactions. The calculations predict the possible transition in magnetic orders (ferromagnetic, antiferromagnetic, and ferrimagnetic) governed by interactions between the MMT nanoclay and the AA molecules in the vacuum and aqueous medium. The significant magnetic exchange coupling observed in some of the nanoclay models, in the presence of an aqueous medium, suggests a unique property of quantum ferrofluids. These findings indicate promising applications of these materials in biomedicine and bioengineering, particularly in the areas requiring an electromagnetic response, such as magnetic resonance and magneto-optical imaging, magnetic drug targeting, hyperthermia cancer treatment, magnetic separation, and magneto-mechanical sensors.
本研究阐明了铁镁共掺杂蒙脱石（MMT）纳米粘土的自旋磁矩对其与三种非天然氨基酸（AAs）：5-氨基戊酸、2-氨基庚二酸和DL-2-氨基辛酸相互作用的敏感性，研究了有无水环境的情况。这些氨基酸是MMT粘土的插层剂，可形成纳米片层。利用自旋极化密度泛函理论（SP-DFT），研究了MMT纳米粘土晶格中铁和镁杂质位置的磁矩及其可调性，以及AA分子在纳米粘土表面的排列情况。AA分子（供体）和MMT纳米粘土（受体）之间存在大量电荷转移，表明它们之间存在强静电相互作用。此外，发现AA分子通过与纳米粘土的强相互作用稳定Fe（II）并防止其氧化为Fe（III），突出了粘土-氨基酸相互作用的重要性。计算预测了在真空和水介质中，由MMT纳米粘土和AA分子之间的相互作用所控制的磁序（铁磁、反铁磁和亚铁磁）的可能转变。在水介质存在的情况下，在一些纳米粘土模型中观察到的显著磁交换耦合表明了量子铁磁流体的独特性质。这些发现表明这些材料在生物医学和生物工程中有广阔的应用前景，特别是在需要电磁响应的领域，如磁共振和磁光成像、磁性药物靶向、热疗癌症治疗、磁分离和磁机械传感器。
