The adsorption of bovine serum albumin (BSA) protein is important for protein research but remains a great challenge. Here, the hydrothermal method and calcination in a hydrogen-argon mixed atmosphere were used to obtain ordered mono-crystalline magnetic Fe3O4 nanorings with controllable size and uniform structure, which were applied to the adsorption of BSA protein. The results showed that the magnetic Fe3O4 nanorings prepared have the advantages of good crystallinity, controllable morphology, and excellent magnetic response. The Fe3O4 nanorings had an outer diameter of ~160–180 nm, inner diameter of ~80–110 nm, and height of 70 to ~110 nm. The amount of BSA adsorbed by magnetic Fe3O4 nanorings increased with increasing protein concentration; when the concentration of BSA was ~2.75 mg·mL-1 the adsorption amount approached saturation. When the pH value of the solution was ~5, the Fe3O4 nanorings absorption of BSA was greatest. With increasing adsorption time, the amount adsorbed increased gradually. Adsorption equilibrium was reached after 3 h. According to the formula, the saturated adsorption capacity of BSA per gram of magnetic Fe3O4 nanorings was 325.2 mg. Graphical Abstract . .

中文翻译：

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用于 BSA 蛋白质吸附的磁性 Fe3O4 纳米环的合成

牛血清白蛋白 (BSA) 蛋白的吸附对于蛋白质研究很重要，但仍然是一个巨大的挑战。在这里，采用水热法和氢氩混合气氛中的煅烧获得尺寸可控且结构均匀的有序单晶磁性Fe3O4纳米环，并将其应用于BSA蛋白的吸附。结果表明，所制备的磁性Fe3O4纳米环具有结晶度好、形貌可控、磁响应优良等优点。Fe3O4 纳米环的外径为~160-180 nm，内径为~80-110 nm，高度为70-110 nm。磁性Fe3O4纳米环吸附BSA的量随着蛋白质浓度的增加而增加；当BSA浓度为~2.75 mg·mL-1时，吸附量接近饱和。当溶液的pH值为~5时，BSA对Fe3O4纳米环的吸收最大。随着吸附时间的增加，吸附量逐渐增加。3小时后达到吸附平衡。根据公式，每克磁性Fe3O4纳米环对BSA的饱和吸附量为325.2mg。图形概要 。.