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In this study, a novel drug delivery system (MSN-PEG-Hypericin) was successfully fabricated using tetraethyl orthosilicate and 3-aminopropyltriethoxysilane as raw materials, and the PEGylation of the prepared aminated mesoporous silica and grafting of hypericin onto the carrier were further conducted to obtain MSN-PEG-Hypericin. The successful preparation of MSN-PEG-Hypericin was characterized by several physical-chemical techniques. Furthermore, the MSN-PEG-Hypericin system increased the ability of hypericin to generate reactive oxygen species (ROS) in vitro. The cytotoxicity assay and hemolysis analysis showed that MSN-PEG-Hypericin had good biocompatibility. For antibacterial studies, the irradiation time and incubation time of photodynamic therapy (PDT) for S. aureus and E. coli were respectively 8 min and 8 h, and the concentrations of hypericin were 2.5 and 5 μg/mL. The result of triphenyl tetrazolium chloride assay indicated that MSN-PEG-Hypericin had stronger photodynamic antibacterial activity than free hypericin, and S. aureus was more sensitive to PDT than E. coli, which was related to their cell structural differences. The antibacterial mechanism study indicated that the generated ROS could destroy the bacterial structures and cause bacterial death due to the leakage of the contents. The MSN-PEG-Hypericin system prepared in this study had potential application prospects in the antibacterial field. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2)-based nanostructures are highly desirable for applications such as chemical and biological sensing, photo/electrochemical catalysis, and energy storage due to their unique physical and chemical properties. In this work, MoS2 core-shell nanoparticles were first prepared through the liquid-phase processing of bulk MoS2 by a femtosecond laser. The core of prepared nanoparticles was incompletely and weakly crystalline MoS2; the shell of prepared nanoparticles was highly crystalline MoS2, which wrapped around the core layer by layer. The femtosecond laser simultaneously achieved liquid-phase ablation and light exfoliation. The formation mechanism of the core-shell nanoparticles is to prepare the nanonuclei first by laser liquid-phase ablation and then the nanosheets by light exfoliation; the nanosheets will wrap the nanonuclei layer by layer through van der Waals forces to form core-shell nanoparticles. The MoS2 core-shell nanoparticles, because of Mo−S bond breakage and recombination, have high chemical activity for chemical catalysis. Afterward, the nanoparticles were used as a reducing agent to directly prepare three-dimensional (3D) Au-MoS2 micro/nanostructures, which were applied as surface-enhanced Raman spectroscopy (SERS) substrates to explore chemical sensing activity. The ultrahigh enhancement factor (1.06×1011), ultralow detection limit (10−13 M), and good SERS adaptability demonstrate highly sensitive SERS activity, great ability of ultralow concentration detection, and ability to detect diverse analytes, respectively. This work reveals the tremendous potential of 3D Au-MoS2 composite structures as excellent SERS substrates for chemical and biological sensing. [ABSTRACT FROM AUTHOR]

A melamine phosphate borate flame retardant was prepared through a solvothermal method and characterized by Fourier transform infrared spectroscopy, scanning electron microscope, element analysis, and X-ray photoelectron spectroscopy. The incorporation of melamine phosphate borate into the phenolic foams toughened by polyethylene glycol results in an increase in limiting oxygen index and a decrease in peak heat release rate, smoke, and CO and CO2production. The mechanical tests reveal that the incorporation of melamine phosphate borate leads to a further improvement in flexural strength and compressive strength, and a decrease in the pulverization ratios of the toughened foams. Moreover, the thermal stability of the toughened PF foams containing melamine phosphate borate was studied. [ABSTRACT FROM AUTHOR]

In this study, a novel drug delivery system (MSN-PEG-Hypericin) was successfully fabricated using tetraethyl orthosilicate and 3-aminopropyltriethoxysilane as raw materials, and the PEGylation of the prepared aminated mesoporous silica and grafting of hypericin onto the carrier were further conducted to obtain MSN-PEG-Hypericin. The successful preparation of MSN-PEG-Hypericin was characterized by several physical-chemical techniques. Furthermore, the MSN-PEG-Hypericin system increased the ability of hypericin to generate reactive oxygen species (ROS) in vitro . The cytotoxicity assay and hemolysis analysis showed that MSN-PEG-Hypericin had good biocompatibility. For antibacterial studies, the irradiation time and incubation time of photodynamic therapy (PDT) for S. aureus and E. coli were respectively 8 min and 8 h, and the concentrations of hypericin were 2.5 and 5 μg/mL. The result of triphenyl tetrazolium chloride assay indicated that MSN-PEG-Hypericin had stronger photodynamic antibacterial activity than free hypericin, and S. aureus was more sensitive to PDT than E. coli , which was related to their cell structural differences. The antibacterial mechanism study indicated that the generated ROS could destroy the bacterial structures and cause bacterial death due to the leakage of the contents. The MSN-PEG-Hypericin system prepared in this study had potential application prospects in the antibacterial field.

Carbon fiber reinforced polymer (CFRP), a highly engineered lightweight material with superior properties, is widely used in industrial fields, such as aerospace, automobile, and railway transportation, as well as medical implants and supercapacitor. This work presents an effective surface treatment method for the controllable fabrication of hydrophilic surface micro/nanostructures of CFRP through femtosecond laser processing. Selective removal of the epoxy resin and leaving the carbon fibers exposed are achieved when CFRP is weakly ablated by a femtosecond laser. The diameters and structures of the carbon fibers can be controlled by adjusting the laser processing parameters. Three-dimensional surface micro/nanostructures are processed when CFRP is strongly ablated by a femtosecond laser. Meanwhile, the transformation of the sp 2 orbitals to sp 3 orbitals of graphitic carbons of carbon fibers is induced by a femtosecond laser. Moreover, the investigation of surface roughness and wettability of femtosecond laser-processed CFRP indicates increased roughness and excellent hydrophilicity (a contact angle of 28.1°). This work reveals the effect of femtosecond laser processing on the regulation of the physicochemical properties of CFRP, which can be applicable to surface treatment and performance control of other fiber-resin composites. The excellent hydrophilicity will be conducive to the combination of CFRP with other materials or to reducing the friction resistance of CFRP used in medical implants., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Based on the use of quercetin for treating diabetes and H 2 S for promoting wound healing, a series of three quercetin-linker-H 2 S donor conjugates was designed, synthesized and characterized by 1 H-NMR, 13 C-NMR and MS. Meanwhile, in vitro evaluation of these compounds was also researched by IR-HepG2 treatment experiment, MTT assay, scratch test and tubule formation experiment. The three compounds could be used to treat insulin resistance induced by high glucose and promote the proliferation of human umbilical vein endothelial cells, wound healing, and the formation of tubules in vitro under a high-glucose environment. Our results illustrate that these compounds could be used to treat diabetes and promote wound healing at the same time. Furthermore, molecular docking study results of the compounds were consistent with the evaluated biological activity. In vivo research of compounds is underway., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)