A salt-driven mechanism for precise chirality sorting of carbon nanotubes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40644550.
- Also identified by DOI 10.1126/sciadv.adx3958 and PMC identifier 12248291.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Sorting single-wall carbon nanotubes (SWCNTs) by chirality/handedness is of substantial scientific and technological importance. Existing sorting methods often lack simplicity, reproducibility and scalability. Here, we demonstrate a salt-driven SWCNT sorting mechanism that addresses these challenges. Various polyethylene glycol (PEG)/salt aqueous two-phase systems effectively modulate the top-phase partitioning of DNA-wrapped SWCNTs (DNA-SWCNTs) across a broad range of hydrophobicities, with cation composition markedly affecting top-phase partitioning in the order NH<sub>4</sub><sup>+</sup> > K<sup>+</sup> > Li<sup>+</sup> > Na<sup>+</sup> closely resembles the well-documented Hofmeister series. We designed PEG/salt systems with defined [K<sup>+</sup>]:[Na<sup>+</sup>] cation ratios to precisely regulate SWCNT partitioning, enabling one-step top-extraction of multiple single-chirality SWCNTs. The cation ratio parameter, determined in small-scale experiments, remains effective at scales 200 times larger, allowing one-step, milligram-scale separation of (-) (6,5) with record-high enantiomeric purity. In addition, we develop a salt-switching multistage bottom-extraction strategy to isolate (+) (6,5) enantiomer. Our method uses simple salts to provide an easy-to-implement, high-precision, scale-invariant, and cost-effective platform for routine SWCNT chirality sorting.