Academic literature on the topic 'Laccase mimetic nanozyme'

Nanozymes (NZs) are catalytically active nanomaterials that have enzyme-like activity but possess increased stability and greater availability due to the fact of their simpler preparation technologies. Nanozymes as nanoscale artificial enzymes demonstrate various catalytic specificities as oxidoreductases, such as peroxidase, catalase, laccase, and others as well as hydrolases, proteases, endonucleases, DNA-ases, NO synthases, etc. A broad variety of NZs exhibits dual- or multienzyme mimetic activity. Nanozymes as stable, low-cost mimetics of natural enzymes have a high potential for application in different branches of biotechnology including scientific investigations, industry, and ecology. Nanozymes can be applied in medicine as diagnostic tools and components of therapeutic drugs. Since NZs have high catalytic activity and chemical and biological stability, they are very promising in the construction of biosensors and biofuel cells. For these reasons, the search for simple methods of synthesis and characterization of different NZs is a very important and real problem. The “green” synthesis of Prussian blue analogous as peroxidase-like NZs using oxido-reductases is described in this study. The obtained green-synthesized hexacyanoferrates (gHCFs) of transition metals were characterized by structure, size, composition, catalytic properties, electro-mediator activities, and substrate specificity. Copper hexacyanoferrate (gCuHCF) was studied in more detail. When immobilized on a graphite electrode (GE), gCuHCF under special conditions of pH and tension gave amperometric signals on hydrogen peroxide and can be used as a peroxidase mimetic in oxidase-based biosensors. Under other conditions, gCuHCF/GE reacts to other analytes. We propose that gHCFs of transition metals synthesized via enzymes may become prospect platforms for the construction of multi-functional amperometric (bio)sensors.

Benefiting from the advantages like large surface area, flexible constitution, and diverse structure, metal-organic frameworks (MOFs) have been one of the most ideal candidates for nanozymes. In this study, a nitro-functionalized MOF, namely NO2-MIL-53(Cu), was synthesized. Multi-enzyme mimetic activities were discovered on this MOF, including peroxidase-like, oxidase-like, and laccase-like activity. Compared to the non-functional counterpart (MIL-53(Cu)), NO2-MIL-53(Cu) displayed superior enzyme mimetic activities, indicating a positive role of the nitro group in the MOF. Subsequently, the effects of reaction conditions on enzyme mimetic activities were investigated. Remarkably, NO2-MIL-53(Cu) exhibited excellent peroxidase-like activity even at neutral pH. Based on this finding, a simple colorimetric sensing platform was developed for the detection of H2O2 and glucose, respectively. The detection liner range for H2O2 is 1–800 μM with a detection limit of 0.69 μM. The detection liner range for glucose is linear range 0.5–300 μM with a detection limit of 2.6 μM. Therefore, this work not only provides an applicable colorimetric platform for glucose detection in a physiological environment, but also offers guidance for the rational design of efficient nanozymes with multi-enzyme mimetic activities.

Nanozymes, which have high enzyme-like activity of natural enzymes, are very promising for analytical purposes, in particular, for the development of methods for sensitive, quantitative detection of practically important analytes – biomarkers of common diseases or pharmaceutical products. Recently, it has been reported that artificial enzymes with laccase-like activity or “nanolaccases (nLacs),” can serve as catalytic elements for the creation of sensitive methods for catecholamines. Our work aimed to obtain laccase-like nanozymes and characterize and demonstrate their suitability for spectrophotometric adrenaline (AD) analysis. In this article, we report on preparing five hexacyanoferrate nanoparticles (HCF NPs) that possess laccase-like activity, particularly, Co-HCF, Ni-HCF, Mn-HCF, Zn-HCF, and Cu-HCF. Among the investigated nLacs, Cu-HCF was selected and characterized. It was shown that Cu-HCF reveals the highest activities, is stable in various pH conditions in the range 3.0–6.5, and has satisfactory stored stability. A new spectrophotometric method for the quantitative detection of AD was created using the selected nLacs. The linearity of the proposed method is in the range from 5 μM to 50 μM (0.66–11 μg/ml), and the limit of detection is 1.5 μM (0.33 μg/ml), which is lower than that catalyzed by native laccase (1.15 μg/ml). The proposed method was tested on the real samples of pharmaceuticals, and the obtained data agree with the data declared by the producer. The resulting nLacs have great potential for use in catalysis of mimetics, environmental restoration, and sensor design. Thus methods, the obtained Cu-HCF has great potential application in spectrophotometric and biosensor method for analysis of biologically active toxic compounds in surface waters.

Nanozymes are nanomaterials which exhibit artificial enzymatic activities and are considered as alternatives to natural enzymes. They are characterized by good catalytic activity and high stability, as well as ease and low cost of preparation. In this study, the mimetics of laccase or “nanolaccases” (NLacs) were synthesized by a simple method of chemical reduction of transition metal salts. The NLacs were tested for their catalytic activity in solution and on the electrode surface. The most effective NLacs, namely nAuCePt and nPtFe, were found to possess excellent laccase-like activities capable of oxidizing the endocrine hormone adrenaline (AD). These NLacs were characterized in detail and used for the development of amperometric sensors for AD determination. The amperometric sensors containing the best NLacs, as well as a natural fungal laccase, were constructed. The most effective nAuCePt-containing sensor had good specificity in relation to AD and improved analytical characteristics. It possessed a 384-fold higher sensitivity than adrenaline (230,137 A·M−1·m−2), a 64-fold lower limit of detection (0.025 µM), and a broader linear range (0.085–45 µM) in comparison with the sensor based on natural laccase. The constructed nAuCePt-containing sensor was successfully used for AD analysis in pharmaceutical formulation.