Modulating the biofunctionality of enzyme-MOF nanobiocatalyst through structure-switching aptamer for continuous degradation of BPA

Functional Metallocenes as Cofactors Promote the Catalytic Performance of Mimetic Enzymes

Coenzymes (cofactors) are essential for bio-redox reactions, group transfer reactions, and heterogeneous reactions of bio-enzymes, as well as the auxiliary transfer of electrons or atoms to promote bio-enzyme activity. However, when mimetic enzymes are scaled to the micro or nanoscale levels, both the absence of cofactor activity and the presence of migrating internal atoms cause self-depletion, eventually limiting sustained usage. Herein, cofactor regulation, a key issue long neglected in traditional mimetic enzyme construction is addressed. In particular, the construction of a mimetic enzyme with monomeric ferrocene is reported. The artificial enzyme consists of both a catalytic center (Fe2+/3+) and a proximate structural unit (functional cyclopentadienyl). The reducing properties of cyclopentadienyl are used as a cofactor to decrease activation energy required to catalyze Fe3+ to Fe2+, lower energy barriers to increase recycling, and, finally, promote electron transfer. This ferrocene-based mimetic enzyme can achieve non-depletion cycle catalysis by keeping the structures and properties of the enzyme constant after the catalytic reaction. Thus, this in situ self-assembly construction of mimetic enzymes using functionalized proximate structural units as cofactors offers a niche concept to solve the predicament of self-depletion such as that seen in traditional mimetic enzymes.

Effective BPA degradation in water: the integration of bimetallic UiO-66 Ce-Zr

In this work, a bimetallic MOF UiO-66 Ce-Zr to degrade bisphenol A (BPA) in water was synthesised. The material exhibited a remarkable degradation efficiency of 84.3% under UV irradiation for 240 minutes. Combining cerium (Ce) and zirconium (Zr) in the MOF structure enhanced the catalytic activity and reinforced its structural stability. Comprehensive characterisation was performed using PXRD, FT-IR, SEM-EDS, XPS, and N₂ adsorption-desorption isotherms. Scavenger tests confirmed that hydroxyl (˙OH) and superoxide (˙O₂⁻) radicals played a crucial role in the photocatalysis. The material demonstrated excellent reusability, maintaining high performance over three cycles with minimal structural changes. Furthermore, a toxicological evaluation of the degradation by-products was conducted using UPLC-MS, reaffirming the potential of the material as an efficient water treatment system. This study underscores the potential of UiO-66 Ce-Zr as a stable and effective photocatalyst for water treatment applications, particularly in removing emerging pollutants such as BPA.

Ultrathin 2D-MOFs for dual-enzyme cascade biocatalysis with sensitive glucose detection performances

In recent years, two-dimensional nanosheet metal-organic frameworks (2D MOFs) have been widely considered as promising carriers for enzyme immobilization owing to their large surface area, designable and tunable structures, and other properties that enhance enzyme loading and modulate interactions with enzymes. In this study, a series of ultrathin 2D M-TCPP (M = Co, Ni, Zn, Cu) nanosheets were synthesized employing a surfactant-assisted bottom-up approach, and the effect of solvent ratio on the morphology and properties of 2D MOFs was explored. After systematic characterization, Cu-based 2D MOFs with large specific surface areas and excellent water stability was selected as the carrier for the co-immobilization of glucose oxidase (GOx) and horseradish peroxidase (HRP). The effects of adsorption and covalent immobilization strategies on bis-enzyme loading and enzyme activity, as well as their applications in rapid glucose detection, were systematically investigated. The results showed that A-CTGH and C-CTGH owned enzyme loadings of 187.9 and 249.1 mg/g, respectively, and exhibited superior enzymatic activity when exposed to harsh environments compared to free enzymes. In addition, the covalently immobilized biocatalyst based on GOx demonstrated a more sensitive glucose detection performance, including a wide linear range from 5.0 to 16 μM with a detection limit of 0.6 μM.

Nanobiohybrids: Synthesis strategies and environmental applications from micropollutants sensing and removal to global warming mitigation

Micropollutants contamination and global warming are critical environmental issues that require urgent attention due to natural and anthropogenic activities posing serious threats to human health and ecosystems. However, traditional technologies (such as adsorption, precipitation, biodegradation, and membrane separation et al.) are facing challenges of low utilization efficiency of oxidants, poor selectivity, and complex in-situ monitoring operations. To address these technical bottlenecks, nanobiohybrids, synthesized by interfacing the nanomaterials and biosystems, have recently emerged as eco-friendly technologies. In this review, we summarize the synthesis approaches of nanobiohybrids and their utilization as emerging environmental technologies for addressing environmental problems. Studies demonstrate that enzymes, cells, and living plants can be integrated with a wide range of nanomaterials including reticular frameworks, semiconductor nanoparticles and single-walled carbon nanotubes. Moreover, nanobiohybrids demonstrate excellent performance for micropollutant removal, carbon dioxide conversion, and sensing of toxic metal ions and organic micropollutants. Therefore, nanobiohybrids are expected to be environmental friendly, efficient, and cost-effective techniques for addressing environmental micropollutants issues and mitigating global warming, benefiting both humans and ecosystems alike.