Biomimetic nanoparticles: U937 cell membranes based core-shell nanosystems for targeted atherosclerosis therapy.

Atherosclerosis (AS), with its intricate pathogenesis, is primarily responsible for the development and progression of cardiovascular diseases. Although drug development has made some achievements in AS therapy, limited targeting ability and rapid blood clearance remain great challenges for achieving superior clinical outcomes. Herein, ginsenoside (Re)- and catalase (CAT)-coloaded porous poly(lactic-coglycolic acid) (PLGA) nanoparticles (NPs) were prepared and then surface modified with U937 cell membranes (UCMs) to yield a dual targeted model and multimechanism treatment biomimetic nanosystem (Cat/Re@PLGA@UCM). The nanoparticles consisted of a core-shell spherical morphology with a favorable size of 112.7 ± 0.4 nm. Furthermore, UCM assisted the nanosystem in escaping macrophage phagocytosis and targeting atherosclerotic plaques. Meanwhile, loading with catalase might not only exhibit favorable antioxidant effects but also enable H2O2-responsive drug release ability. The Cat/Re@PLGA@UCM NPs also exhibited outstanding ROS scavenging properties, downregulating ICAM-1, TNF-α and IL-1ß, while preventing angiogenesis to attenuate the progression of AS. Moreover, the nanodrugs displayed 2.7-fold greater efficiency in reducing the atherosclerotic area in ApoE-/- mouse models compared to free Re. Our nanoformulation also displayed excellent biosafety in response to long-term administration. Overall, our study demonstrated the superiority of UCM-coated stimuli-responsive nanodrugs for effective and safe AS therapy.

[Display of glucose oxidase on Bacillus subtilis spore surface and preparation for enzyme electrode].

Glucose biosensor is currently the most common electrochemical biosensor. Most glucose biosensors are prepared by modifying glucose oxidase on the electrode surface. However, in the process of electrode immobilization, enzyme purification is required, which increases the cost and has become a bottleneck in the field of development of immobilized enzyme electrodes. In this study, glucose oxidase (GOD) was displayed on the surface of Bacillus subtilis using the spore capsid protein CotX as an anchor protein. By Western blotting analysis, immunofluorescence analysis and enzyme activity detection, GOD was effectively expressed on the surface of spores, and recombinant spores (Spore-GOD) were obtained by fermentation. The graphene oxide/prussian blue deposition film modified glassy carbon electrode was prepared by the drop coating method and the electrodeposition method. The surface of the modified electrode was fixed with Spore-GOD, and finally covered with a layer of Nafion solution to make an electrochemical biosensor for sensitive determination of glucose. The cyclic voltammogram of glucose on the enzyme electrode sensor showed a well-defined oxidation peak at 0.42 V, and the redox peak current has a good linear relationship with the glucose concentration in the range of 0.1-7.0 mmol/L. The calibration curve equation is: I=1.305C(glucose)+3.639 (R²=0.992 9), and its detection limit is 7.5 µmol/L (S/N=3). This modified electrode has good conductivity, stability and reproducibility, and can be used for the analysis and determination of glucose.

Conductive Hydrogels-A Novel Material: Recent Advances and Future Perspectives.

A conductive hydrogel is a kind of polymer material having substantial potential applications with various properties, including high toughness, self-recoverability, electrical conductivity, transparency, freezing resistance, stimuli responsiveness, stretchability, self-healing, and strain sensitivity. Herein, according to the current research status of conductive hydrogels, properties of conductive hydrogels, preparation methods of different conductive hydrogels, and their application in different fields, such as sensor and actuator fabrication, biomedicine, and soft electronics, are introduced. Furthermore, the development direction and application prospects of conductive hydrogels are proposed.

Trehalose Production Using Recombinant Trehalose Synthase in Bacillus subtilis by Integrating Fermentation and Biocatalysis.

Trehalose, a stable nonreducing disaccharide, protects biomolecules against environmental stress. However, trehalose production using secretory trehalose synthase (TreS) by Bacillus subtilis has not been well studied. In this study, a mutant TreS was successfully secreted and expressed in B. subtilis WB800N. The extracellular enzyme activity of TreS regulated by the P43 promoter and SPPhoD signal peptide in recombinant B. subtilis WB800N reached 23080.6 ± 1119.4 U/L in a 5-L fermenter after optimizing the culture medium, while xpF, skfA, lytC, and sdpC were knocked out. To reduce maltose consumption, malP and amyE corresponding to maltose transporters were further deleted. To simplify the trehalose production process, we invented a fermentation-coupling biocatalysis process involving recombinant bacteria fermentation to secrete TreS and simultaneous conversion of maltose to trehalose by TreS and found that the conversion rate of maltose to trehalose reached 75.5%, suggesting that this is an efficient strategy for large-scale trehalose production using recombinant B. subtilis.