Here, lamellar membranes with hydrophilic/hydrophobic heterostructured nanochannels are constructed by alternately stacking graphene oxide (GO) and reduced graphene oxide (RGO) nanosheets via dual-needle electrostatic atomization. This technology exhibits facile controllability over membrane nanostructure, where the dual-needle device can compel active reactants to contact in confined space. Through subtly designing spraying parameters, GO and RGO nanosheets can be alternately deposited on the substrate to construct heterostructured nanochannels. And we demonstrate that the asymmetric channel wall-molecule interactions can induce molecule stratification for acetonitrile/water mixture, where hydrophilic GO layer exerts strong attraction to acetonitrile, whereas water molecules are pushed to hydrophobic RGO layer. Then, the strong attraction further induces acetonitrile molecules to form orderly aligned aggregates and transfer quickly, while water molecules are randomly distributed and transfer slowly. The pre-determined different transfer rates afford a high acetonitrile permeance of 38.9 L m –2 h −1 bar −1 and separation factor of acetonitrile/water up to 4.8, surpassing that of homostructured lamellar membranes. Furthermore, this stratification and hence separation performance can be enhanced by channel length, acetonitrile amount in feed, operation temperature and pressure. The first discovery of molecule stratification in heterostructured nanochannels facilitates the sustainable development of advanced separation membranes.
Junrong Li,Meiqin Li,Alain Wuethrich,Rui Guan,Lihui Zhao,Cong Hu,Matt Trau,Yao Sun
Development of molecular diagnostics for lung cancer stratification and monitoring is crucial for the rational planning and timely adjustment of treatments to improve clinical outcomes. In this regard, we propose a nanocavity architecture to sensitively profile the protein signature on small extracellular vesicles (sEVs) to enable accurate, noninvasive staging and treatment monitoring of lung cancer. The nanocavity architecture is formed by molecular recognition through the binding of sEVs with the nanobox-based core–shell surface-enhanced Raman scattering (SERS) barcodes and mirrorlike, asymmetric gold microelectrodes. By imposing an alternating current on the gold microelectrodes, a nanofluidic shear force was stimulated that supported the binding of sEVs and the efficient assembly of the nanoboxes. The binding of sEVs further induced a nanocavity between the nanobox and the gold microelectrode that significantly amplified the electromagnetic field to enable the simultaneous enhancement of Raman signals from four SERS barcodes and generate patient-specific molecular sEV signatures. Importantly, evaluated on a cohort of clinical samples (n = 76) on the nanocavity architecture, the acquired patient-specific sEV molecular signatures achieved accurate identification, stratification, and treatment monitoring of lung cancer patients, highlighting its potential for transition to clinical utility.
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