Fe3O4@OA@Poloxamer nanoparticles lower triglyceride in hepatocytes through liposuction effect and nano-enzyme effect

Bioconjugation of nanozyme and natural enzyme to enable a one-step cascade reaction for the detection of metabolites

Nanozyme, with enzyme-mimicking activity and excellent stability, has attracted extensive attention. However, some inherent disadvantages, including poor dispersion, low selectivity, and insufficient peroxidase-like activity, still limit its further development. Therefore, an innovative bioconjugation of a nanozyme and natural enzyme was conducted. In the presence of graphene oxide (GO), histidine magnetic nanoparticles (H-Fe₃O₄) were first synthesized by a solvothermal method. The GO-supported H-Fe₃O₄ (GO@H-Fe₃O₄) exhibited superior dispersity and biocompatibility because GO was the carrier and possessed outstanding peroxidase-like activity because of the introduction of histidine. Furthermore, the mechanism of the peroxidase-like activity of GO@H-Fe₃O₄ was the generation of •OH. Uric acid oxidase (UAO) was selected as the model natural enzyme and covalently linked to GO@H-Fe₃O₄ with hydrophilic poly(ethylene glycol) as a linker. UAO could specifically catalyze the oxidation of uric acid (UA) to generate H₂O₂, and subsequently, the newly produced H₂O₂ oxidized the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue ox-TMB under the catalysis of GO@H-Fe₃O₄. Based on the above cascade reaction, the GO@H-Fe₃O₄-linked UAO (GHFU) and GO@H-Fe₃O₄-linked ChOx (GHFC) were used for the detection of UA in serum samples and cholesterol (CS) in milk, respectively. The method based on GHFU exhibited a wide detection range (5-800 μM) and a low detection limit (1.5 μM) for UA, and the method based on GHFC exhibited a wide detection range (4-400 μM) and a low detection limit (1.13 μM) for CS. These results demonstrated that the proposed strategy had great potential in the field of clinical detection and food safety.

Iron oxide nanoparticles for biomedical applications: an updated patent review (2015-2021)

INTRODUCTION

Iron oxide nanoparticles (IONPs) hold the edges of great magnetic properties and fine nanoparticle characteristics, making them an attractive therapeutic agent. In the past seven years, more in-depth investigations were devoted to the intrinsic structure, magnetic properties, and biological effects of IONPs, expanding the range of their therapeutic application scenes.

AREAS COVERED

This review focuses on the development of IONPs for biomedical applications from the angle of the patent literature reported during the period 2015-2021.

EXPERT OPINION

While the magnetic properties of IONPs have been extensively explored, the precise control of IONP behavior through external magnetic fields remains a challenge. Further digging into the biological effects of IONPs will facilitate the development of IONP-based immune therapies. Long-term reliable safety evaluations are of necessity and significance to promote the process of clinical translation.

Mesoporous peroxidase nanozyme for synergistic chemodynamic therapy and chemotherapy

Peroxidase nanozyme, enabling decomposition of hydrogen peroxide (H₂O₂) into highly toxic hydroxyl radical (•OH), is an emerging technology for tumor treatment. However, limited by the low H₂O₂ level in the tumor microenvironment, the standalone peroxidase nanozyme-mediated therapy usually fails to achieve desirable therapeutic outcomes. Herein, we presented a mesoporous nanozyme that not only had peroxidase-like activity but also could deliver anticancer drug for synergistic tumor therapy. The nanozyme, that was, iron-doped mesoporous silica nanoparticle (FeMSN), was prepared by a sol-gel method and then a calcination treatment. The introduction of iron endowed FeMSN with peroxidase-like activity that could decompose H₂O₂ into •OH under acidic condition for chemodynamic therapy of tumors. Meanwhile, the mesoporous structure enabled FeMSN to deliver anticancer drug doxorubicin (DOX) for chemotherapy and enhanced chemodynamic therapy through H₂O₂ production, ultimately achieving synergistic effect to improve the efficacy of tumor treatment. The in-vitro and in-vivo results demonstrated that DOX-loaded FeMSN exhibited significant cancer cell-killing effect and potently inhibited tumor growth. Collectively, this study represented a paradigm for achieving efficient tumor therapy through design of peroxidase-like nanozyme with drug delivery capability, which might advance the development of nanozyme in tumor chemodynamic therapy.

Cur@SF NPs alleviate Friedreich's ataxia in a mouse model through synergistic iron chelation and antioxidation

Abnormal iron metabolism, mitochondrial dysfunction and the derived oxidative damage are the main pathogeneses of Friedrich's ataxia (FRDA), a single-gene inherited recessive neurodegenerative disease characterized by progressive cerebellar and sensory ataxia. This disease is caused by frataxin (FXN) mutation, which reduces FXN expression and impairs iron sulfur cluster biogenesis. To date, there is no effective therapy to treat this condition. Curcumin is proposed harboring excellent ability to resist oxidative stress through Nrf2 activation and its newly found ability to chelate iron. However, its limitation is its poor water solubility and permeability. Here, we synthesized slow-release nanoparticles (NPs) by loading curcumin (Cur) into silk fibroin (SF) to form NPs with an average size of 150 nm (Cur@SF NPs), which exhibited satisfactory therapeutic effects on the improvement of FRDA manifestation in lymphoblasts (1 μM) derived from FRDA patients and in YG8R mice (150 mg/kg/5 days). Cur@SF NPs not only removed iron from the heart and diminished oxidative stress in general but also potentiate iron-sulfur cluster biogenesis, which compensates FXN deficiency to improve the morphology and function of mitochondria. Cur@SF NPs showed a significant advantage in neuron and myocardial function, thereby improving FRDA mouse behavior scores. These data encourage us to propose that Cur@SF NPs are a promising therapeutic compound in the application of FRDA disease.

Polyphenols extracted from Shanxi-aged vinegar exert hypolipidemic effects on OA-induced HepG2 cells via the PPARα-LXRα-ABCA1 pathway

Hyperlipidemia is one of the key risk factors causing many chronic diseases, and lowering blood lipid levels can prevent many diseases. In this paper, a hyperlipidemic cell model of oleic acid (OA) induced hepatocellular carcinoma cells (HepG2) was established using polyphenols extracted from Shanxi-aged vinegar (SAVEP). The effects of SAVEP on nuclear damage, mitochondrial membrane potential, apoptosis, cellular lipid deposition, and lipid metabolism protein expression in HepG2 hyperlipidemic cells were examined to investigate the lipid-lowering mechanism of SAVEP at the cellular level. The results showed that SAVEP could reduce the content of TC/TG index, repair the nuclear damage, reduce lipid accumulation and finally decrease the rate of apoptosis by up-regulating the expression of key proteins such as PPARα, LXRα, and ABCA1 in the process of lipid metabolism. PRACTICAL APPLICATIONS: In this thesis, the hypolipidemic activity of polyphenol extracts from Shanxi-aged vinegar was analyzed on the level of HepG2 cells. The hypolipidemic mechanism of oxidative stress, lipid metabolism and inflammatory stress was also elucidated. It provided a theoretical basis for the in-depth understanding of the hypolipidemic health effects of Shanxi-aged vinegar.

Design of Hepatic Targeted Drug Delivery Systems for Natural Products: Insights into Nomenclature Revision of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-dysfunction-associated fatty liver disease (MAFLD), affects a quarter of the worldwide population. Natural products have been extensively utilized in treating NAFLD because of their distinctive advantages over chemotherapeutic drugs, despite the fact that there are no approved drugs for therapy. Notably, the limitations of many natural products, such as poor water solubility, low bioavailability in vivo, low hepatic distribution, and lack of targeted effects, have severely restricted their clinical application. These issues could be resolved via hepatic targeted drug delivery systems (HTDDS) that boost clinical efficacy in treating NAFLD and decrease the adverse effects on other organs. Herein an overview of natural products comprising formulas, single medicinal plants, and their crude extracts has been presented to treat NAFLD. Also, the clinical efficacy and molecular mechanism of active monomer compounds against NAFLD are systematically discussed. The targeted delivery of natural products via HTDDS has been explored to provide a different nanotechnology-based NAFLD treatment strategy and to make suggestions for natural-product-based targeted nanocarrier design. Finally, the challenges and opportunities put forth by the nomenclature update of NAFLD are outlined along with insights into how to improve the NAFLD therapy and how to design more rigorous nanocarriers for the HTDDS. In brief, we summarize the up-to-date developments of the NAFLD-HTDDS based on natural products and provide viewpoints for the establishment of more stringent anti-NAFLD natural-product-targeted nanoformulations.

Immobilization of glyceraldehyde-3-phosphate dehydrogenase on Fe3O4 magnetic nanoparticles and its application in histamine removal

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Lactobacillus plantarum is a novel biocatalyst in the degradation of histamine, but its properties need enhancement before practical application. Herein, we used Fe₃O₄ magnetic nanoparticles (MNPs) as the carrier core to prepare immobilized GAPDH. GAPDH was cloned, expressed in E. coli and purified, followed by immobilization on Fe₃O₄ MNPs and characterization by TEM and FT-IR. Then, characteristic comparisons between immobilized enzyme and its free form showed that the optimal pH and temperature of the former shifted to 7.5 and 40 °C, respectively, and pH tolerance and thermostability were separately broadened to 4.5-8.5 and 50-60 °C. In a wine-making experiment, including grape and black raspberry wines, using the immobilized enzyme, the results showed that over 81 %, 75 % and 59 % of histamine was removed after each treatment. These findings demonstrate that immobilizing GAPDH onto Fe₃O₄ MNPs is facile and efficient for histamine removal in fermented beverages.