Spherical materials capable of binding to negatively charged biomembrane bearing species like bacterial cells in still or flowing liquids can have a number of important applications. For example, they could be used to remove bacterial cells from blood facilitating the diagnosis and treatment of bacteremia (i.e., bacterial infection of blood). Other applications involve removal of such species from aqueous foodstuffs, pharmaceutical formulations, and wastewater discharges. Here we report of the preparation of bis(dipicolylamine) (BDPA) bearing nonporous cellulose microspheres (CMs) for the sequestration of negatively charged biomembrane bearing species. When complexed with Zn²⁺ ions, BDPA ligands are capable of binding to biomembranes that display negatively charged phosphate amphiphiles on their outer surfaces. Three different chemical ligation strategies (amide bond formation, reductive amination, and epoxide opening) were employed to obtain BDPA derivatized CMs. Using fluorescence microscopy and spectroscopy it was demonstrated that these BDPA-CMs were capable of binding to negatively charged liposomes, but not to neutral liposomes. Fluorescence microscopy also revealed that all the BDPA-CMs were capable of binding to green fluorescent protein-expressing Escherichia coli (K12). Quantification of bacterial binding of one of these BDPA-CMs revealed binding capacities of 1.01 × 10⁸ colony forming units (CFU)/g for E. coli (K12) through fluorescence spectroscopy, and ≥ 8.96 × 10⁷ and 5.93 × 10⁷ CFU/g respectively for E. coli (ATCC 35049) and Staphylococcus aureus (ATCC 25923) using optical density measurements at 600 nm (OD₆₀₀). Such high binding capacities make these materials good candidates for future applications where sequestration of bacterial cells and other species with similar membrane properties from liquids is desired.

Graphical abstract

中文翻译：

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双（二吡啶甲胺）衍生化纤维素微球用于隔离带负电荷的生物膜轴承物种

能够与带负电荷的生物膜承载物种（如静止或流动液体中的细菌细胞）结合的球形材料可以具有许多重要应用。例如，它们可用于从血液中去除细菌细胞，从而促进菌血症（即血液的细菌感染）的诊断和治疗。其他应用包括从水性食品、药物制剂和废水排放中去除此类物质。在这里，我们报告了带有无孔纤维素微球 (CM) 的双（二甲基吡啶甲胺）(BDPA) 的制备，用于隔离带负电荷的生物膜轴承物种。^{与 Zn 2+}络合时离子，BDPA 配体能够与生物膜结合，生物膜在其外表面显示带负电荷的磷酸盐两亲物。采用三种不同的化学连接策略（酰胺键形成、还原胺化和环氧化物开环）来获得 BDPA 衍生化 CM。使用荧光显微镜和光谱法证明这些 BDPA-CM 能够与带负电荷的脂质体结合，但不能与中性脂质体结合。荧光显微镜还显示所有 BDPA-CM 都能够与表达绿色荧光蛋白的大肠杆菌(K12) 结合。对其中一种 BDPA-CM 的细菌结合进行定量显示，大肠杆菌的结合能力为 1.01 × 10 ⁸菌落形成单位 (CFU)/g(K12) 通过荧光光谱，使用 600 nm (OD ₆₀₀ )的光密度测量，大肠杆菌(ATCC 35049) 和金黄色葡萄球菌(ATCC 25923) 分别≥ 8.96 × 10 ⁷和 5.93 × 10 ⁷  CFU/g 。如此高的结合能力使这些材料成为未来应用的良好候选者，在这些应用中，需要从液体中隔离细菌细胞和其他具有类似膜特性的物种。

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