Department of Chemical and Biomolecular Engineering , University of Houston , Houston , Texas 77204-4004 , United States.
Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States.
ACS Appl Mater Interfaces. 2018 Sep 5;10(35):29288-29298. doi: 10.1021/acsami.8b08579. Epub 2018 Aug 24.
A critical aspect of material synthesis is solvent structuring at solid-liquid interfaces, which can impact the adsorption of solute and growth modifiers on an underlying substrate. In general, the impact of solvent structuring on molecular sorbate interactions with solid sorbents is poorly understood. This is particularly true for processes that occur in organic media, such as hematin crystallization, which is crucial to the survival of malaria parasites. Here, we use chemical force microscopy and molecular modeling to analyze the interactions between functional moieties of known antimalarials and the interface between β-hematin crystals and a mixed organic (octanol)-aqueous solvent. We show that the β-hematin surface, patterned in parallel hydrophobic and hydrophilic stripes, engenders the assembly of up to five layers of octanol molecules aligned parallel to the crystal surface. In contrast, studies of solvent structuring on a disordered glass surface reveal that octanol molecules align perpendicular to the interface. The distinct octanol arrays direct molecule adsorption at the respective interfaces. At both substrates, we also find stabilized pockets of aqueous nanophase lining the surfaces. A combination of experimental analyses and modeling of solvent structuring provides crucial insights into the association of hematin molecules with growing crystals as well as the adsorption and mobility of antimalarial drugs. Moreover, our findings offer a general perspective on the collective behaviors of complex organic solvents that may apply to a broad range of interactions at solid-liquid interfaces.
物质合成的一个关键方面是固液界面处的溶剂结构，这会影响溶质和生长调节剂在基底上的吸附。一般来说，溶剂结构对分子吸附剂与固体吸附剂相互作用的影响理解得还不够充分。对于在有机介质中发生的过程尤其如此，例如血红素结晶，这对疟原虫的生存至关重要。在这里，我们使用化学力显微镜和分子建模来分析已知抗疟药物的功能部分与β-血红素晶体和混合有机（辛醇）-水溶剂之间界面之间的相互作用。我们表明，β-血红素表面按平行的疏水性和亲水性条纹图案化，会引起多达五层的辛醇分子平行于晶体表面排列。相比之下，对无序玻璃表面上溶剂结构的研究表明，辛醇分子垂直于界面排列。独特的辛醇阵列将分子吸附定向在各自的界面上。在两种基底上，我们还发现水的纳米相的稳定口袋沿着表面排列。溶剂结构的实验分析和建模的组合为血红素分子与生长晶体的结合以及抗疟药物的吸附和迁移提供了重要的见解。此外，我们的发现为复杂有机溶剂的集体行为提供了一个普遍的视角，这可能适用于固液界面上广泛的相互作用。
