Abstract
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.
Original language | English |
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Pages (from-to) | 193-203 |
Number of pages | 11 |
Journal | Nano Letters |
Volume | 25 |
Issue number | 1 |
DOIs | |
State | Published - Jan 8 2025 |
Funding
We acknowledge the Center for Nanophase Materials and Sciences at Oak Ridge National Laboratory for STM imaging and Vanderbilt Institute of Nanoscale Science and Engineering for CORE facility for material characterization. This work was supported in part by Chan Zuckerberg Initiative DAF and Silicon Valley Community Foundation dynamic imaging grant DAF2020-225394, in part by NSF CAREER award #1944134, and in part by DOE Early Career Research Program award # DE-SC0022915 to P.R.K. N.F. acknowledges NSF CAREER award #2216394.
Keywords
- atomically thin membranes
- graphene
- highly selective membranes
- nanoscale separations
- protein-enabled defect sealing