Atomically thin 2D materials present the potential for advancing membrane separations via a combination of high selectivity (from molecular sieving) and high permeance (due to atomic thinness). However, the creation of a high density of precise nanopores (narrow-size-distribution) over large areas in 2D materials remains challenging, and nonselective leakage from nanopore heterogeneity adversely impacts performance. Here, we demonstrate protein-enabled size-selective defect sealing (PDS) for atomically thin graphene membranes over centimeter scale areas by leveraging the size and reactivity of permeating proteins to preferentially seal larger nanopores (≥4 nm) while preserving a significant amount of smaller nanopores (via steric hindrance). Our defect-sealed nanoporous atomically thin membranes (NATMs) show stability up to ∼35 days during size-selective diffusive separations with a model dialysis biomolecule fluorescein isothiocyanate (FITC)-Ficoll 70 in phosphate buffer saline (PBS) solution as well as outperform state-of-the-art commercially available dialysis membranes (molecular-weight-cutoff ∼3.5–5 kDa and ∼8–10 kDa) with significantly higher permeance for smaller solutes KCl (∼0.66 nm) ∼5.1–6 × 10^–5 ms^–1 and vitamin B12 (B12, ∼1.5 nm) ∼2.8–4 × 10^–6 ms^–1 compared to small protein lysozyme (Lz, ∼4 nm) ∼4–6.4 × 10^–8 m s^–1, thereby allowing unprecedented selectivity for B12/Lz ∼70 and KCl/Lz ∼1280. Our work introduces proteins as nanoscale tools for size-selective defect sealing in atomically thin membranes to overcome persistent issues and advance separations for dialysis, protein desalting, small molecule separations/purification, and other bioprocesses.

中文翻译：

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用于透析和纳米级分离的原子薄 2D 膜的蛋白质尺寸选择性缺陷密封


原子薄的 2D 材料通过高选择性（来自分子筛分）和高渗透性（由于原子薄性）的组合，具有推进膜分离的潜力。然而，在 2D 材料中大面积创建高密度的精确纳米孔（窄尺寸分布）仍然具有挑战性，并且纳米孔异质性的非选择性泄漏会对性能产生不利影响。在这里，我们通过利用渗透蛋白质的大小和反应性优先密封较大的纳米孔 （≥4 nm），同时保留大量较小的纳米孔（通过空间位阻），展示了用于厘米级面积上原子薄石墨烯膜的蛋白质尺寸选择性缺陷密封 （PDS）。我们的缺陷密封纳米多孔原子薄膜 （NTAM） 在尺寸选择性扩散分离过程中表现出长达 ∼35 天的稳定性，使用模型透析生物分子异硫氰酸荧光素 （FITC）-Ficoll 70 在磷酸盐缓冲盐水 （PBS） 溶液中，性能优于最先进的市售透析膜（截留分子量 ∼3.5–5 kDa 和 ∼8–10 kDa），对较小溶质 KCl （∼0.66 nm） ∼5.1–6 × 10^–5 ms^–1 的渗透率明显更高与小蛋白溶菌酶（Lz，∼4 nm）∼4-6.4 × ^10-8 m s^–1 相比，维生素 B12（B12，∼1.5 nm）∼2.8-4 × ^10-6 ms^–1，因此对 B12/Lz ∼70 和 KCl/Lz ∼1280 具有前所未有的选择性。我们的工作将蛋白质作为纳米级工具，用于原子薄膜中的尺寸选择性缺陷密封，以克服持续存在的问题并推进透析、蛋白质脱盐、小分子分离/纯化和其他生物过程的分离。