Biomimetic Catalysis Research Articles

Supramolecular Systems Chemistry Based on the Interplay between Peptides and Porphyrins

The functions of living organisms are emergent from networks of biomolecules. In this review, we discuss the creation of synthetic life‐like systems based on the interplay of peptides and porphyrins in the supramolecular chemical systems. In particular, we focus on the spatiotemporal control of self‐assembly processes, which allows for the development of hierarchical structures for biomimetic catalysis and adaptive dynamics for stimulus‐responsive structural transformations. Notably, when operating in a nonequilibrium regime—characterized by kinetic traps, feedback loops, and dissipative conditions—the structural landscape expands and system‐level properties emerge, including transient catalysis, metabolic self‐replication, and Darwinian‐like evolution. Controlling these systems at the biointerface would facilitate intelligent therapeutic interventions in the anti‐tumor phototherapy. Supramolecular systems chemistry provides a valuable framework for exploring new physicochemical spaces of peptides and porphyrins, and may offer distinct advantages and extensive applications across diverse fields.

Immobilized Multi-Enzyme/Nanozyme Biomimetic Cascade Catalysis for Biosensing Applications.

Multiple enzyme-induced cascade catalysis has an indispensable role in the process of complex life activities, and is widely used to construct robust biosensors for analyzing various targets. The immobilized multi-enzyme cascade catalysis system is a novel biomimetic catalysis strategy that immobilizes various enzymes with different functions in stable carriers to simulate the synergistic catalysis of multiple enzymes in biological systems, which enables high stability of enzymes and efficiency enzymatic cascade catalysis. Nanozymes, a type of nanomaterial with intrinsic enzyme-like characteristics and excellent stabilities, are also widely applied instead of enzymes to construct immobilized cascade systems, achieving better catalytic performance and reaction stability. Due to good stability, reusability, and remarkably high efficiency, the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems show distinct advantages in promoting signal transduction and amplification, thereby attracting vast research interest in biosensing applications. This review focuses on the research progress of the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems in recent years. The construction approaches, factors affecting the efficiency, and applications for sensitive biosensing are discussed in detail. Further, their challenges and outlooks for future study are also provided.

Exploring Enzyme-Mimicking Metal-Organic Frameworks for CO2 Conversion through Vibrational Spectra-Based Machine Learning.

In pursuing the benefits of natural enzyme catalysts while overcoming their limitations, we find metal-organic frameworks (MOFs), renowned for their highly tunable functionalities, stand out in biomimetic applications. We used unsupervised machine learning on density functional theory-computed vibrational infrared and Raman spectral features to screen 300 Zn-MOFs for CO2 conversion, similar to carbonic anhydrase (CA). Our findings confirmed that MOFs with spectroscopic attributes closely resembling those of CA hold the potential for replicating CA's electronic and catalytic properties. Unlike previous studies that relied on heuristic or trial-and-error methods and focused on geometric configurations, our research uses vibrational spectral features to explore structure-property relationships, making them more accessible through spectroscopy. Moreover, we highlight vibrational spectral features as efficient carriers for highly dimensional chemical information, enabling the simultaneous optimization of multiple performance parameters. These findings pave the way for pioneering designs of enzyme-mimetic MOFs and concurrently expand the application scope of spectroscopic tools in biomimetic catalysis.

Using Gold‐Nanoparticles‐Based Nanozyme to Accelerate the Self‐Assembly of Silk Fibroin

AbstractThe design and development of nanomaterials with intrinsic enzyme‐like activities (nanozymes) have attracted huge interest during the past several decades. Herein, by incorporating the concept of nanozyme‐involved biomimetic catalysis into the molecular assembly, we introduce an exciting example of utilizing the gold nanozyme system to expedite the sol‐gel transition of silk fibroin. In this system, silica‐encapsulated gold nanoparticles (MSN‐AuNPs) possess an intrinsic glucose oxidase‐like activity, and the activity of AuNPs has been studied by using first‐principles calculations. The catalytic oxidization of glucose into gluconic acid by MSN‐AuNPs leads to a significant decrease in the pH value of silk fibroin solution, rapidly accelerating the self‐assembly of silk fibroin solution into physical hydrogel. Since nanozymes can be further remotely controlled via different stimuli, this simple, rational control and accelerated method is a significant breakthrough, will lead to a large pool of opportunities for further exploration of nanozymes in the field of molecular assembly.

Dual‐Site Trigger Electronic Communication Effects to Accelerate H2O2 Activation for Colorimetric Sensing of Uranyl Ions in Seawater

AbstractEfficient activation of hydrogen peroxide (H2O2) through biomimetic catalysis still faces a major challenge. In this work, inspired by the catalytic pocket of natural peroxidase, Cu single atom (CuSA) and AuCu nanoparticles (AuCuNPs) anchored on nitrogen‐doped carbon skeleton (CuSA‐AuCuNPs/NC) serve as dual active sites that significantly accelerate the charge transfer process and thus achieve efficient H2O2 activation. Meanwhile, the experimental and theoretical calculations show that the well‐established electronic communication effect between CuSA and AuCuNPs results in moderate electronic modifications to CuSA, which promotes the heterolysis of H2O2 and the timely desorption of H2O. As a proof of concept, CuSA‐AuCuNPs/NC show remarkable performance in detecting uranyl ions in seawater. This work provides new insights into the H2O2 activation for colorimetric sensing.

Luminescent gold nanoclusters loaded on iron metal–organic framework with enhanced peroxidase-like activity for the colorimetric/fluorescent determination of H2O2

In this work, a composite nanozyme, termed AuNCs/Fe-MIL, was obtained by combining glutathione-stabilized gold nanoclusters (AuNCs) on the surface of the Fe metal–organic framework (Fe-MIL-88B-NH2). The AuNCs/Fe-MIL nanocomposite retains the red emission of AuNCs, exhibiting unique dual-emission fluorescence with remarkable stability. This nanozyme exhibits improved peroxidase-like activity as a result of the heightened rate of electron transfer. As a result, the decomposition of H2O2 is accelerated, leading to the generation of more •OH radicals that oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into blue ox-TMB. The generated ox-TMB can quench the fluorescence of AuNCs/Fe-MIL in the red-light region. By leveraging the dual function of the catalytic product ox-TMB, a fusion of colorimetric and fluorescence signals enabled H2O2 detection within 10 min. The sensing platform demonstrated wide linear ranges of 5–1000 μM with a detection limit of 2.78 μM in colorimetry mode and 5–500 μM with a detection limit of 0.78 μM in fluorescence mode. This method was successfully utilized for accurate in situ monitoring of H2O2 release from different types of living cells. Additionally, a dual-mode portable sensing platform based on AuNCs/Fe-MIL/TMB hydrogel was constructed for convenient H2O2 detection. Through a smartphone application, precise quantitation of H2O2 added to milk samples was achieved. This work provides a rational design of multifunctional nanozymes for reliable biomimetic catalysis.

High-entropy oxide based biomimetic catalysis system enables robust oxidative desulfurization with an excellent regeneration ability

Sulfur-containing compounds from the usage of fossil fuel have severe impacts on the ecological environment and human health. To eliminate sulfur species in fuels, oxidative desulfurization is served as an effective technology, whose core lies in constructing an efficient catalytic system under mild conditions. High-entropy oxides (HEOs) with maximized conformational entropy normally generates abundant catalytically active sites, which are beneficial for the enhancement in catalytic performance. On this basis, a biomimetic catalytic system coupling HEO with deep eutectic solvent (DES) was designed for oxidative desulfurization with molecular O2 oxidant by following the electron transfer mechanism. This catalytic system not only exhibited excellent sulfide removal with O2 oxidant under the ambient pressure, but also can resist the adverse effects of naphthalene and indole in an appropriate concentration range. Uniquely, this HEO was capable to be recovered from the DES phase, ensuring a good recycling and regeneration ability. During the whole catalytic process, the electron was transferred in the sequence of sulfide → DES → HEO → O2. These extraordinary features make it to be an alternative candidate for industrial applications under mild conditions.

Cu/Mn Synergy Catalysis-Based Colorimetric Sensor for Visual Detection of Hydroquinone

The reliable detection of environmental contaminants can correctly forecast the degree of environmental pollution that has occurred, which contributes to improving the environmental purification rate and maintaining the ecological balance. Herein, a novel hierarchical biomimetic catalysis MnO2@CuAl-CLDHs was designed and synthesized using a facile method, which exhibited significantly enhanced peroxidase-like activity due to the unique composition and hierarchical mesoporous structure. Under optimized operational conditions, a visible colorimetric array based on the superior nanozyme activity of MnO2@CuAl-CLDHs was developed for the quantitative determination of hydroquinone with a wide linear detection range (1–100 μM) and a low detection limit (0.183 μM). Simultaneously, our presented strategy could analyze hydroquinone in real water samples with high accuracy. Therefore, the bimetallic co-catalyzed nanozymes are expected to be the perfect replacement for natural enzymes to develop convenient and efficient sensors.

CATALYTIC ACTIVITY OF METAL-BASED IONIC LIQUIDS IN OXIDATIVE DESULFURIZATION

Effective desulfurization techniques are required due to the operational and environmental difficulties caused by sulfur compounds found in petroleum fuels. The use of Fenton catalysts in the oxidative desulfurization of petroleum fuels is examined in this work. Evaluating the viability and effectiveness of Fenton catalysts in lowering sulfur concentration while maintaining fuel quality is the main goal. Promising outcomes are found in laboratory tests using hydrogen peroxide (H2O₂) and ferrous iron (Fe³⁺) as catalysts. Fenton catalysts focus on sulfur compounds and transform them into forms that are soluble in water, making the process of separating them from the fuel easier. This procedure offers a more environmentally friendly and financially feasible desulfurization option because it works in milder circumstances than other techniques. The results provide a viable path for the development of sustainable fuel and have ramifications for greener energy sources and environmental legislation. There has been a growing interest in ionic liquids (ILs) as innovative materials for functional desulfurization. Based on their definition and fundamental structure, metal-based ionic liquids (MILs) are divided into three categories in this critical article: metal chloride MILs, metal oxide MILs, and metal complex MILs. To enhance the oxidative desulfurization (ODS) process, MILs have both the oxidation and absorption sites for intramolecular adsorption and oxidation. A noteworthy characteristic of MILs in ODS is biomimetic catalysis, which serves to enhance oxidation performance by triggering molecular oxygen. Hydrogen peroxide or oxygen combined with the available water, together with metal oxide and metal complex ions, create a Fenton-like reaction that transforms hydrophobic organic sulfur (SO2) or hydrophilic sulfoxide/sulfone (Seroxide), or sulfur acid, respectively. Promising approaches for developing environmentally friendly and highly effective desulfurization procedures for large-scale applications are also given. Keywords: supported ionic liquid catalyst (SILC), hydrogen peroxide, catalytic oxidative desulfurization, copper (I) chlorocomplexes.

Biomimetic Dual-Network Collagen Fibers with Porous and Mechanical Cues Reconstruct Neural Stem Cell Niche via AKT/YAP Mechanotransduction after Spinal Cord Injury.

Tissue engineering scaffolds can mediate the maneuverability of neural stem cell (NSC) niche to influence NSC behavior, such as cell self-renewal, proliferation, and differentiation direction, showing the promising application in spinal cord injury (SCI) repair. Here, dual-network porous collagen fibers (PCFS) are developed as neurogenesis scaffolds by employing biomimetic plasma ammonia oxidase catalysis and conventional amidation cross-linking. Following optimizing the mechanical parameters of PCFS, the well-matched Young's modulus and physiological dynamic adaptability of PCFS (4.0wt%) have been identified as a neurogenetic exciter after SCI. Remarkably, porous topographies and curving wall-like protrusions are generated on the surface of PCFS by simple and non-toxic CO2 bubble-water replacement. As expected, PCFS with porous and matched mechanical properties can considerably activate the cadherin receptor of NSCs and induce a series of serine-threonine kinase/yes-associated protein mechanotransduction signal pathways, encouraging cellular orientation, neuron differentiation, and adhesion. In SCI rats, implanted PCFS with matched mechanical properties further integrated into the injured spinal cords, inhibited the inflammatory progression and decreased glial and fibrous scar formation. Wall-like protrusions of PCFS drive multiple neuron subtypes formation and even functional neural circuits, suggesting a viable therapeutic strategy for nerve regeneration and functional recovery after SCI.

Revving up a Designed Copper Nitrite Reductase Using Non-Coded Active Site Ligands.

Herein, we report a three stranded coiled-coil (3SCC) de novo protein containing a type II copper center (CuT2) composed of 6-membered ring N-heterocycles. This design yields the most active homogenous copper nitrite reductase (CuNiR) mimic in water. We achieved this result by controlling three factors. First, previous studies with Nδ and Nε -Methyl Histidine had indicated that a ligand providing pyridine-like electronic character to the copper site was superior to the more donating Nδ for nitrite reduction. By substitution of the parent histidine with the non-coded amino acids pyridyl alanine (3'-Pyridine [3'Py] vs 4'-Pyridine [4'Py]), an authentic pyridine donor was employed without the complications of the coupling of both electronic and tautomeric effects of histidine or methylated histidine. Second, by changing the position of the nitrogen atom within the active site (4'-Pyridine vs. 3'Pyridine) a doubling of the enzyme's catalytic efficiency resulted. This effect was driven exclusivity by substrate binding to the copper site. Third, we replaced the leucine layer adjacent to the active site with an alanine, and the disparity between the 3'Py and 4'Py became more apparent. The decreased steric bulk minimally impacted the 3'Py derivative; however, the 4'Py K m decreased by an order of magnitude (600 mM to 50 mM), resulting in a 40-fold enhancement in the k cat/K m compared to the analogues histidine site and a 1500-fold improvement compared with the initially reported CuNiR catalyst of this family, TRIW-H. When combined with XANES/EXAFS data, the relaxing of the Cu(I) site to a more 2-coordinate Cu(I) like structure in the resting state increases the overall catalytic efficiency of nitrite reduction via the lowering of K m. This study illustrates how by combining advanced spectroscopic methods, detailed kinetic analysis, and a broad toolbox of amino acid side chain functionality, one can rationally design systems that optimize biomimetic catalysis.

Integration of multienzyme co-immobilization and biomimetic catalysis in magnetic metal–organic framework nanoflowers for α-amylase detection in fermentation samples

Multiple enzymes induce biological cascade catalysis is essential in nature and industrial production. However, the shortcomings of enzymes, including unsatisfactory stability, reusability, and sensitivity in harsh microenvironment, have restricted their broader use. Here, we report a facile method for fabricating a cascade system by combining the benefits of immobilized enzymes and biomimetic catalysis based on magnetic metal–organic framework nanoflowers (mMOFNFs). mMOFNFs prepared through the layered double hydroxide-derived strategy exhibited remarkable peroxidase-like activity and accessible amino interface, enabling it to serve not only as a reliable carrier for α-glucosidase and glucose oxidase fixation, but also as a nanozyme participating in cascade. On this basis, a colorimetric biosensor of excellent sensitivity and selectivity for α-amylase detection was constructed with a wide range (2–225 U L−1), low detection limit (2.48 U L−1), and rapid operation (30 min). This work provides a versatile strategy for establishing multi-enzyme cascade systems and rapid analysis of α-amylase.

Enhanced biomimetic catalysis via self-cascade photocatalytic hydrogen peroxide production over modified carbon nitride nanozymes for total antioxidant capacity evaluation

The peroxidase mimics usually requires the addition of exogenous hydrogen peroxide (H2O2), which greatly hinder their practical applications. Herein, through rational co-modification of multiple elements (potassium (K), chlorine (Cl) and iodine (I)), the modified carbon nitride nanomaterials (KCl/KI-CN) could serve as efficient bifunctional catalysts. The multiple elements doping and the incorporation of cyano groups (CN) are deemed to enhance their photocatalytic and peroxidase-like activity, respectively. Based on the photocatalytic function, H2O2 can be produced continuously and steadily via two-electron oxygen reduction over modified carbon nitride under visible light irradiation. Subsequently, the KCl/KI-CN could catalyze the chromogenic substrate by the in-situ produced H2O2. Taking advantage of the bifunctional properties of modified carbon nitride, we for the first time demonstrate a self-cascade catalytic process and apply successfully for the ascorbic acid (AA) detection and versatile total antioxidant capacity (TAC) evaluation. This paper not only prepares an efficiently bifunctional catalyst but also provides a new self-cascade photocatalytic H2O2 production strategy for the peroxidase-like application.

Supramolecular Hydrolase Mimics in Equilibrium and Kinetically Trapped States

AbstractThe folding of proteins into intricate three‐dimensional structures to achieve biological functions, such as catalysis, is governed by both kinetic and thermodynamic controls. The quest to design artificial enzymes using minimalist peptides seeks to emulate supramolecular structures existing in a catalytically active state. Drawing inspiration from the nuanced process of protein folding, our study explores the enzyme‐like activity of amphiphilic peptide nanosystems in both equilibrium and non‐equilibrium states, featuring the formation of supramolecular nanofibrils and nanosheets. In contrast to thermodynamically stable nanosheets, the kinetically trapped nanofibrils exhibit dynamic characteristics (e.g., rapid molecular exchange and relatively weak intermolecular packing), resulting in a higher hydrolase‐mimicking activity. We emphasize that a supramolecular microenvironment characterized by an optimal local polarity, microviscosity, and β‐sheet hydrogen bonding is conducive to both substrate binding and ester bond hydrolysis. Our work underscores the pivotal role of both thermodynamic and kinetic control in impacting biomimetic catalysis and sheds a light on the development of artificial enzymes.

Supramolecular Hydrolase Mimics in Equilibrium and Kinetically Trapped States.

The folding of proteins into intricate three-dimensional structures to achieve biological functions, such as catalysis, is governed by both kinetic and thermodynamic controls. The quest to design artificial enzymes using minimalist peptides seeks to emulate supramolecular structures existing in a catalytically active state. Drawing inspiration from the nuanced process of protein folding, our study explores the enzyme-like activity of amphiphilic peptide nanosystems in both equilibrium and non-equilibrium states, featuring the formation of supramolecular nanofibrils and nanosheets. In contrast to thermodynamically stable nanosheets, the kinetically trapped nanofibrils exhibit dynamic characteristics (e.g., rapid molecular exchange and relatively weak intermolecular packing), resulting in a higher hydrolase-mimicking activity. We emphasize that a supramolecular microenvironment characterized by an optimal local polarity, microviscosity, and β-sheet hydrogen bonding is conducive to both substrate binding and ester bond hydrolysis. Our work underscores the pivotal role of both thermodynamic and kinetic control in impacting biomimetic catalysis and sheds a light on the development of artificial enzymes.

Opportunities and challenges for plastic depolymerization by biomimetic catalysis.

Plastic waste has imposed significant burdens on the environment. Chemical recycling allows for repeated regeneration of plastics without deterioration in quality, but often requires harsh reaction conditions, thus being environmentally unfriendly. Enzymatic catalysis offers a promising solution for recycling under mild conditions, but it faces inherent limitations such as poor stability, high cost, and narrow substrate applicability. Biomimetic catalysis may provide a new avenue by combining high enzyme-like activity with the stability of inorganic materials. Biomimetic catalysis has demonstrated great potential in biomass conversion and has recently shown promising progress in plastic degradation. This perspective discusses biomimetic catalysis for plastic degradation from two perspectives: the imitation of the active centers and the imitation of the substrate-binding clefts. Given the chemical similarity between biomass and plastics, relevant work is also included in the discussion to draw inspiration. We conclude this perspective by highlighting the challenges and opportunities in achieving sustainable plastic recycling via a biomimetic approach.

Advances in chromone-based copper(ii) Schiff base complexes: synthesis, characterization, and versatile applications in pharmacology and biomimetic catalysis.

Chromones are well known as fundamental structural elements found in numerous natural compounds and medicinal substances. The Schiff bases of chromones have a much wider range of pharmacological applications such as antitumor, antioxidant, anti-HIV, antifungal, anti-inflammatory, and antimicrobial properties. A lot of research has been carried out on chromone-based copper(ii) Schiff-base complexes owing to their role in the organometallic domain and promise as potential bioactive cores. This review article is centered on copper(ii) Schiff-base complexes derived from chromones, highlighting their diverse range of pharmacological applications documented in the past decade, as well as the future research opportunities they offer.

Aerobic oxidative C-C bond formation through C-H bond activation catalysed by flavin and iodine.

We report a metal/light-free aerobic oxidative C-C bond formation using sp3 C-H bond activation of tetrahydroisoquinolines catalyzed by flavin and iodine. The dual catalytic system enabled the oxidative Mannich and aza-Henry reactions by the cross-dehydrogenative coupling between two sp3 C-H bonds. Furthermore, the flavin-iodine-coupled catalysis was applied to the synthesis of pyrrolo[2,1-a]isoquinolines through the sequential oxidative 1,3-dipolar cycloaddition and dehydrogenative aromatization. The biomimetic flavin catalysis efficiently activates molecular oxygen; thus the non-metal dual catalytic system enables green oxidative transformation using molecular oxygen as an environmentally friendly terminal oxidant which generates benign water.

Molybdenum-maltolate as a molybdopterin mimic for bioinspired oxidation reaction.

A novel cis-dioxomolybdenum(VI)-maltolate [MoO2(Mal)2] (1) is prepared as a stable molybdopterin model for the biomimetic catalysis of the oxidation of hypoxanthine in acetonitrile-water at room temperature. Compound 1 efficiently catalyzes the oxidation reaction of toluene, diphenylmethane, and styrene. Cyto- and oral-toxicity studies suggest its tremendous potential for application as a molybdenum supplement.

A sensing platform for ascorbic acid based on the spatial confinement of covalent organic frameworks

Essential to many activities in our bodies, ascorbic acid is a small molecule essential to human health and physiological processes. In this study, a covalent organic framework called TpNda-COF was synthesized, which is composed of Tp (triformylephloroglucinol) and Nda (1, 5-napthalenediamine). This framework acts as a mimic enzyme and displays excellent oxidase-like activity when stimulated with purple light (at = 405 nm). It catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzydine (TMB) by generating O2− free radicals in the presence of oxygen. The resulting oxTMB shows a characteristic absorption peak at 652 nm. The biomimetic catalysis efficiency is significantly improved due to spatial restriction. By introducing ascorbic acid (AA) in the system, the blue oxTMB is reduced to colorless TMB. The decrease in absorption peak intensity can be quantitatively measured using a UV–Vis spectrophotometer, enabling the detection of AA. The sensing platform demonstrates excellent selectivity and sensitivity. It has a wide linear detection range from 5 μM to 50 μM, with a low detection limit of 1.44 μM. Advantages such as the easy control of light, high stability and efficient oxidation are provided by the TpNda-COF mimic oxidase. This innovative method presents a promising and cost-effective approach for rapid detection of ascorbic acid, with potential applications across various fields.