Insight into Bioactivity of In‐situ Trapped Enzyme‐Covalent‐Organic Frameworks

Abstract

Selecting a suitable support material for enzyme immobilization with excellent biocatalytic activity and stability is a critical aspect in the development of functional biosystems. The highly stable and metal-free properties of covalent-organic frameworks (COFs) make them ideal supports for enzyme immobilization. Herein, we constructed three kinds of COFs via a biofriendly and one-pot synthetic strategy at room temperature in aqueous solution. Among the three developed COFs (COF-LZU1, RT-COF-1 and ACOF-1), the horseradish peroxidase (HRP)-incorporated COF-LZU1 is found to retain the highest activity. Structural analysis reveals that a weakest interaction between the hydrated enzyme and COF-LZU1, an easiest accessibility by the COF-LZU1 to the substrate, as well as an optimal conformation of enzyme together promote the bioactivity of HRP-COF-LZU1. Furthermore, the COF-LZU1 is revealed to be a versatile nanoplatform for encapsulating multiple enzymes. The COF-LZU1 also offers superior protection for the immobilized enzymes under harsh conditions and during recycling. The comprehensive understanding of interfacial interactions of COF host and enzyme guest, the substrate diffusion, as well as the enzyme conformation alteration within COF matrices represents an opportunity to design the ideal biocatalysts and opens a broad range of applications of these nanosystems.

Covalent-organic framework nanobionics for robust cytoprotection

“…Synthesis and characterization of COF-coated yeast cells COF-LZU1, based on our previous research, was selected as the ideal nanocoating for yeast cells due to its weak host-guest interaction and substrate accessibility. 36 The encapsulation of S. cerevisiae cells within COF-LZU1-based exoskeletons (referred to as yeast-COF) involved a sequential addition of 1 mL of cell suspensions (with an optical density at 600 nm (OD600) of 1.0), 1 mL of p-phenylenediamine (PPDA) (10 mg mL −1 ), 10 mL of benzene-1,3,5-tricarboxaldehyde (BTCA) (0.5 mg mL −1 ), and 1 mL of acetic acid (1.742 M). Aer a 5 minute reaction, 0.9 mL of NaOH (4 M) was added, followed by an additional 10 minute reaction.…”

“…1a, iii). 36 Numerous cellular activities, such as cell identication, metabolism, protein synthesis, and survival, are regulated by receptors on the cell surface. To gain insight into how the exoskeletons changed yeast cell fate, gene expression proles of the yeast cell and yeast-COF were subjected to transcriptomics analysis.…”

“…35 Recent advancements in biofriendly COF synthesis strategies for enzyme encapsulation have further sparked interest in exploring COFs as durable and robust nanocoatings for living cells. [36][37][38] The appealing features of COFs, including acidic stability, metal-free composition, precisely tunable functionalities and pore geometries, topological diversity, and well-dened structures, hold the potential to confer living cells with unprecedented properties.…”

A Multifunctional Covalent Organic Framework Nanozyme for Promoting Ferroptotic Radiotherapy against Esophageal Cancer

“…Since being defined in 2005, COFs have typically been synthesized in sealed ampules via solvothermal reactions. Regulating their morphology under such conditions poses difficulties, resulting in multiple phases being produced. − By contrast, ambient synthesis, especially at room temperature, offers a homogeneous nucleation process and greater control over the morphology of crystal products. − Therefore, nanoscale COFs with high crystallinity and good homogeneity can be easily prepared by adjusting crystallization conditions, such as solvent type, monomer concentration, and acidity. , Herein, imine-linked TADI-COF was obtained as a yellow microcrystalline powder by reacting 1,3,5-tris­(4-aminophenyl)­benzene and 2,5-diiodoterephthalaldehyde in acetonitrile/methyl acetate (2:1, v/v) with acetic acid at room temperature for 2 d. Fc-functionalized TADI-COF-Fc was prepared as a dark brown crystalline solid via the imine condensation reaction between the free amino group on TADI-COF and ferrocenecarboxaldehyde (FcCHO) in ethanol with a catalytic amount of acetic acid. The formation of TADI-COF and TADI-COF-Fc was further supported by the high-yield syntheses of the model compounds, 1-(2-iodophenyl)- N -phenylmethanimine (CCDC 2278318, Table S1, and Figure S1) and N -(ferrocenylmethylidene)­aniline (Figure S2).…”

Light-Switchable Biocatalytic Covalent–Organic Framework Nanomotors for Aqueous Contaminants Removal

“…To tackle the aforementioned challenges, we chose covalent–organic frameworks (COFs) as the foundation for the nanomotor due to their highly customizable molecular structure and porosity. Recent reports have highlighted pioneering endeavors of MNMs designed based on metal–organic frameworks (MOFs), which are “siblings” of COFs, both being reticular porous nanomaterials. − Moverover, recent advancements in biofriendly COF synthesis strategies have further sparked interest in exploring COFs for the integration and protection of biocatalysts (i.e., enzymes) within the framework, ensuring a high loading of catalysts without the need for complex fabrication processes. − This protective COF layer shields the biomolecules from intricate and potentially harmful external environments while simultaneously maintaining or even enhancing their biocatalytic efficiency. , As a result, enzyme@COF constructs have emerged as a promising strategy for various biological and environmental applications. − On the other hand, enzymes, being a type of naturally abundant biocatalyst, display remarkable catalytic efficiency. This enables them to catalyze reactions more rapidly, requiring lower catalyst loading and demanding less fuel than some inorganic catalysts.…”