Nanoarchitectonics of a MOF-in-Nanochannel (HKUST-1/TiO2) Membrane for Multitarget Selective Enrichment and Staged Recovery

Chiral Membrane Containing Subnanometer Channels for Enantioselective Transport Amino Acids

The research of chiral separation technology is of great significance for understanding the origin of life and promoting the application of chiral molecules. Herein, anionic chiral pillar[6]arene and cationic pillar[6]arene were designed and synthesized, and a chiral pillar[6]arene membrane was constructed by layer-by-layer assembly through electrostatic interactions. The transport rates of l-Ala and d-Ala in this channel were 14.33 and 1.86 μM cm-2 h-1, respectively, and the transport rate of l-Ala was 7.7 times that of d-Ala. In the transport experiment of Ala racemate, the ee value of l-Ala in the permeate after a single separation was 62%, indicating that this channel has a certain chiral separation ability. The effects of the assembly method, the number of chiral layers, and the driving force on the separation effect were further studied, and the selective transport mechanism was explored through the host-guest interaction at the molecular level and theoretical simulation. This strategy provides a new template for expanding the application of chiral pillar[n]arenes in the field of membrane separation.

Metal organic frameworks-in-nanochannels: A tailorable chromatography membrane for isolation of target protein

Metal-organic frameworks (MOFs) demonstrate strong potential in biosample separation. However, the obtained MOFs powders are unsuitable for recovery techniques in an aqueous solution, especially the challenges of withdrawing MOFs particles and expanding their functions for specific applications. Herein, a general strategy is designed utilizing metal oxide-nanochannel arrays as precursors and templates for in-situ selective growth of MOFs structures. The exemplary MOFs (Ni-bipy) with tailored composition are selectively grown in NiO/TiO₂ nanochannel membrane (NM) using NiO as the sacrificial precursor, which enables one to achieve a ∼262 times concentration of histidine-tagged proteins within 100 min. The significantly improved adsorption efficiency in a wide pH range and the effective enrichment from a complex matrix as a nanofilter illustrate the great potential of MOFs in nanochannels membranes for the high-efficiency recovery of essential proteins in complex biological samples. The porous self-aligned Ni-MOFs/TiO₂ NM exhibits biocompatibility and flexible functionalities, which is desirable for the generation of multifunctional nanofilter devices and developing biomacromolecule delivery vehicles.