فهرست مطالب محمدعلی فرامرزی

The spread of drug resistance and limited effects of antibiotics on the pathogenic biofilms along with the increasing number of hospital infections have imposed heavy costs on the healthcare system. In the present study, quercetin-barium phosphate hybrid nanostructures were fabricated and characterized in order to improve their antibiofilm activity.

To prepare hybrid nanostructures, barium sulfate was added to sodium phosphate buffer containing quercetin (0.1 mg mL–1), the reaction mixture was sonicated for 10 min, and the obtained precipitate was collected. To obtain the hybrid nanostructures with the maximum immobilized quercetin, the concentrations of phosphate buffer and barium sulfate were examined in the range of 50–250 mM and 10–50 mM, respectively. The prepared hybrid nanostructures were characterized using scanning electron microscopy, infrared spectroscopy, and X-ray diffraction analysis, their effects were evaluated in preventing and destroying bacterial biofilms as well.

The immobilization yield of quercetin within hybrid structures was 95%. The scanning electron microscope images showed fiber-like structures with smooth, knot-free, and uniform surfaces. Quercetin-barium phosphate hybrid nanofibers significantly inhibited the biofilm formation in Pseudomonas aeruginosa and Staphylococcus aureus by 100% and 80%. Also, in the presence of the immobilized quercetin (500 mg L–1), biofilms of Staphylococcus aureus and Bacillus subtilis were destroyed by 75% and 70%.

Due to the notable antibiofilm properties of quercetin-barium phosphate hybrid nanofibers, they could be useful in medical devices, and therapeutic and environmental processes.

Organic-inorganic hybrid nanoflowers with flower-like morphology are new nanostructures comprising organic and inorganic components. In general, the organic component of hybrid nanoflowers mostly consists of proteins, DNA, RNA, plant extracts, metabolites, and natural polymers; and the inorganic component composes of various metal phosphates, including copper, calcium, manganese, iron, zinc, cobalt, cadmium, aluminum, silver, gold, etc. Until now, five notable procedures have been introduced for their synthesis, including biomineralization, ultra-fast sonication, the two-step method, shear stress, and the concentrated method. These nanostructures have many promising applications in diverse fields, such as the immobilization of enzymes and biomolecules, bio-catalysis of chemical reactions, bioremediation, electrochemical biosensors, drug and gene carriers, diagnosis of various diseases, photothermal therapy, etc., and wide range of research has been performed on them in the last recentdecade.Google Scholar, Scopus, ScienceDirect, and Springer databases were searched using the keywords hybrid nanostructure, nanoflower, biosciences, and biocatalyst to find related articles.Studying these organic-inorganic hybrid nanocrystals may lead to finding new creative solutions in the effective application of enzyme-based systems, the rapid development of bionanomaterials, and biotechnology industries. The present review has investigated the different types of hybrid nanoflowers, their synthesis procedures and structural characteristics, and their applications in biosciences.

In this study, we used a simple green method for preparing tellurium nanoparticles and mainly evaluated their toxicological effects. The nanoparticles were synthesized using lactose and characterized with different instrumentation methods. The in vitro and in vivo cytotoxicity of tellurium nanoparticles and its effect on lipid profile were also evaluated. Hydroxyl-capped tellurium nanoparticles were successfully fabricated by lactose. The results showed spherical tellurium nanoparticles with a mean size of 89 nm. The toxicological study showed that the tellurium nanoparticles did not exhibit any toxicity on the primary cells. The LD50 values for the nanoparticles were 327 and 295 mg/kg for oral and intraperitoneal administrations, respectively. Also, the results showed a significant reduction in liver enzymes at the 16, 24, and 40 mg/kg doses. Hematological parameters indicated no significant suppressive changes between the animals that were administered tellurium nanoparticles and the control group. In addition, the effects of tellurium nanoparticles on hypercholesterolemic risk factors in mice fed with cholesterol demonstrated the depletion of triglyceride, cholesterol, and low-density lipoprotein. This study showed that the toxicity of tellurium nanoparticles was lower than tellurium ions. Furthermore, tellurium nanoparticles decreased the cholesterol and triglyceride levels in the animal model.