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

Enrichment and separation of specific endogenous molecules are essential for disease diagnosis and the pharmaceutical industry. Although many solid sorbents have been developed for target molecule enrichment, simultaneous separation of multitargets is still a challenge for adsorbents. In this study, we develop a multitarget selective sorbent based on a nanochannel membrane prepared by the anodization of a Ti-Cu alloy. The in situ growth of a metal-organic framework (MOF, herein using Cu-based HKUST-1) in the nanochannels enables the resulting MOF-in-nanochannel membrane to act as a nanofilter. Benefitting from the size-exclusion effect of MOFs and the distinct surface characteristics of each component in the HKUST-1/TiO2 nanochannels, the as-proposed membranes can be simply operated as a filter and exhibit satisfactory selectivities and enrichment capacities in the separation of aromatic amino acids, histidine-rich proteins, and phosphoproteins. More importantly, the adsorbed multitargets can be further controllably released from the membrane in a sequence via a staged recovery process. The use of this system is envisioned to provide an innovative and potential design for efficient sorption media for the selective enrichment and staged separation of specific biomolecules.