ABSTRACT
Liver fibrosis is a reversible pathological process caused by chronic liver damage and a major risk factor for hepatocellular carcinoma (HCC). Hepatic stellate cell (HSC) activation is considered the main target for liver fibrosis therapy. However, the efficiency of this strategy is limited due to the complex microenvironment of liver fibrosis, including excessive extracellular matrix (ECM) deposition and hypoxia-induced imbalanced ECM metabolism. Herein, nilotinib (NIL)-loaded hyaluronic acid (HA)-coated Ag@Pt nanotriangular nanozymes (APNH NTs) were developed to inhibit HSCs activation and remodel the microenvironment of liver fibrosis. APNH NTs efficiently eliminated intrahepatic reactive oxygen species (ROS) due to their inherent superoxide dismutase (SOD) and catalase (CAT) activities, thereby downregulating the expression of NADPH oxidase-4 (NOX-4) and inhibiting HSCs activation. Simultaneously, the oxygen produced by the APNH NTs further alleviated the hypoxic microenvironment. Importantly, the released NIL promoted collagen depletion by suppressing the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), thus synergistically remodeling the microenvironment of liver fibrosis. Notably, an in vivo study in CCl4-induced mice revealed that APNH NTs exhibited significant antifibrogenic effects without obvious long-term toxicity. Taken together, the data from this work suggest that treatment with the synthesized APNH NTs provides an enlightening strategy for remodeling the microenvironment of liver fibrosis with boosted antifibrogenic activity.
ABSTRACT
Regulating the catalytic activity of nanozymes is significant for their applications in various fields.Here,we demonstrate a new strategy to achieve reversible regulation of the nanozyme's activity for sensing purpose.This strategy involves the use of zero-dimensional M0S2 quantum dots(MQDs)as the building blocks of nanozymes which display very weak peroxidase(POD)-like activity.Interestingly,such POD-like activity of the MQDs largely enhances in the presence of Fe3+while diminishes with the addition of captopril thereafter.Further investigations identify the mechanism of Fe3+-mediated aggregation-induced enhancement of the POD-like activity and the inhibitory effect of captopril on the enhance-ment,which is highly dependent on their concentrations.Based on this finding,a colorimetric method for the detection of captopril is developed.This sensing approach exhibits the merits of simplicity,rapidness,reliability,and low cost,which has been successfully applied in quality control of captopril in pharmaceutical products.Moreover,the present sensing platform allows smartphone read-out,which has promising applications in point-of-care testing devices for clinical diagnosis and drug analysis.
ABSTRACT
A new electrochemical sensor for organophosphate pesticide(methyl-paraoxon)detection based on bifunctional cerium oxide(CeO2)nanozyme is here reported for the first time.Methyl-paraoxon was degraded into p-nitrophenol by using CeO2 with phosphatase mimicking activity.The CeO2 nanozyme-modified electrode was then synthesized to detect p-nitrophenol.Cyclic voltammetry was applied to investigate the electrochemical behavior of the modified electrode,which indicates that the signal enhancement effect may attribute to the coating of CeO2 nanozyme.The current research also studied and discussed the main parameters affecting the analytical signal,including accumulation potential,accumulation time,and pH.Under the optimum conditions,the present method provided a wider linear range from 0.1 to 100 μmol/L for methyl-paraoxon with a detection limit of 0.06 μmol/L.To validate the proof of concept,the electrochemical sensor was then successfully applied for the determination of methyl-paraoxon in three herb samples,i.e.,Coix lacryma-jobi,Adenophora stricta and Semen nelum-binis.Our findings may provide new insights into the application of bifunctional nanozyme in electro-chemical detection of organophosphorus pesticide.
ABSTRACT
Due to their high catalytic activity and substrate specificity, enzymes have broad applications in commodity chemistry, medicine, food manufacturing, pollution prevention and control, etc. However, their actual applications are compromised by disadvantages such as difficulty to separate and purify, high cost and poor stability. It is of great significance to explore artificial substitutes for enzymes. Ferroferric oxide nanoparticles were reported to have peroxidase-like activity by Dr. Xiyun Yan for the first time in 2007. Since then the researches about nanomaterials with catalytic activities have emerged in large numbers. In addition to peroxidase-like activities, nanomaterials also possessed many enzyme-like catalytic activities such as oxidase, superoxide dismutase and catalase. Nanomaterials with enzyme-like activities are usually referred as nanozymes. As an alternative to natural enzymes, nanozymes possess characteristics such as low costs, easy mass production, high stability and adjustable activity. Those nanozyme characteristics have broad applications in environmental monitoring and management, disease diagnosis and treatment, food safety control, etc. However, low catalytic efficiency and specificity limit further applications of nanozymes. Therefore, enhancing the catalytic activities and selectivity of nanozymes will promote their applications. The catalytic activity of nanozymes can be regulated by changes in nanomaterials (size, morphology and surface modification) and catalytic reaction conditions (temperature, pH, accelerators, light irradiation, etc.), mixing of different nanomaterials, nanomaterial hybridization, and so on. The most widely used catalytic activity of nanozymes is peroxidase-like activity. This review summarizes the strategies to enhance peroxidase-like activities of nanomaterials, mainly focuses on catalytic efficiency and substrate specificity. It is expected that readers can have a comprehensive understanding of the strategies to enhance the enzyme-like activity of nanomaterials.
ABSTRACT
The combination of chemotherapy and photodynamic therapy provides a promising approach for enhanced tumor eradication by overcoming the limitations of each individual therapeutic modality. However, tumor is pathologically featured with extreme hypoxia together with the adaptable overexpression of anti-oxidants, such as glutathione (GSH), which greatly restricts the therapeutic efficiency. Here, a combinatorial strategy was designed to simultaneously relieve tumor hypoxia by self-oxygenation and reduce intracellular GSH level to sensitize chemo-photodynamic therapy. In our system, a novel multi-functional nanosystem based on MnO
ABSTRACT
Lateral flow assay is widely used in the point-of-care testing on-site and in-home testing with the advantage of being simple, rapid, sensitive and cost-effective. Proper labels are the key factors in lateral flow assay. Traditional labels include colloidal gold, selenium nanoparticle, and carbon nanoparticle, among which the colloidal gold is most commonly used. Lateral flow assay has been improved as a result of the discovery of new labels, such as quantum dots and nanozyme recently. Meanwhile, transformation of qualitative detection to quantitative detection is gradually realized. This article aims at introducing the most often used and the latest lateral flow assay labels, providing a basis theoretical investigation on screening proper labels for lateral flow assay researchers.