MOF-enzyme hybrid nanosystem decorated 3D hollow fiber membranes for in-situ blood separation and biosensing array

Modified metal-organic frameworks (MOFs) doping with enzymes exhibit high enzyme stability and catalytic performance, which is a research hotspot in the field of enzyme-based sensing. Although the MOF-enzyme constitutes a 3D structure in the nanoscale, the macroscopic assembly configuration still stays in 1D or 2D structures, limiting sensing applications towards complex biological targets. Herein, the MOF-enzyme hybrid nanosystem was assembled into 3D porous conductive supports via a controllable physical embedding method, displaying high enzymatic loading, stability and cascade catalytic performance. The modified MOFs combing with enzymes served as a sensing reaction system, and the conductive hollow fiber membranes (HFMs) served as a functional platform. The multifunctional device integrates pumpless hydrodynamic transport, interconnected conductive polymer, and blood separation modules, showing fast capillary fluid flow, trace sampling (3 μL), high selectivity and accuracy. The linear sensing range was in 2-24 mM glucose, 0.05-6 mM lactic acid, and 0.1-10 mM cholesterol, respectively, with sensitivities of 24.2, 150, 73.6 nA mM^-1. Furthermore, this strategy of modular assembly of biosensing array can easily implement multiplex metabolites detection simultaneously.

Biocatalytic membrane: Go far beyond enzyme immobilization

Biocatalytic membrane takes advantages of reaction-separation integration as well as enzyme immobilization, which has attracted increasing attentions in online detection and biomanufacturing. However, the high preparation cost, inferior comprehensive performance, and low stability limit its applications. Thus, besides enzyme immobilization, more efforts should be made in biocatalytic membrane configuration design for a specific application to enhance the synergistic effect of reaction and separation and improve its operating stability. This review summarized the recent progress on biocatalytic membrane preparation, discussed different membrane configurations for various applications, finally proposed several challenges and possible solutions, which provided directions and guides for the development and industrialization of biocatalytic membrane.

Electrochemical mercury biosensors based on advanced nanomaterials

This review presents an overview of the synthesis strategies and electrochemical performance of recently developed nanomaterials for the Hg²⁺ assay.