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.

Nowadays, magnetotactic bacteria have attracted the attention of scientists due to their green synthesis of nanoparticles. Magnetic nanoparticles enclose within the magnetosome; the bacterial intracellular organelle with a double-layered membrane which causes them to taxi the south and north poles of the earth. Bacteria synthesize magnetosomes in low oxygen conditions. Magneto-tactic bacteria are often isolated from the water sediments. All the magnetosome-forming bacteria are Gram-negative. Until now all of the identified Magnetotactic bacteria are among 13 phyla of 34 culturable phyla: Proteobacteria, Nitrospirota, Omnitrophota, Latescibacterota, Planctomycetota, Nitrospinota, Hydrogenedentota, Elusimicrobiota, Fibrobacterota, Riflebacteria, Bdellovibrionota, UBA1019, and desulfobacterota. The origin of magnetic behavior and magnetosome genes among all MTB is supposed to be acquired by horizontal gene transfer in different phyla. Magnetotactic bacteria have an -891gene core genome related to magnetotaxis named the magnetosome island. Some of the genes associated with proteins as Mam B, MamQ, MamT, MamM, MamK, and MamA (Mam: magnetosome membrane) are essential for magnetosome formation. Magnetosomes have various applications, such as sensing, diagnostics, remediation, immobilization of catalysts, and targeted delivery. Biosynthetic magnetite nanoparticles compared to those synthetic chemicals have exciting properties: they are permanently magnetic at room temperature, have high purity, and illustrate a uniform shape and size, low toxicity due to their membrane envelope, ferrimagnetic attributes, and dispersal capability, which are essential for their potential industrial applications. Due to the importance of magnetosomes in various applications and their unique characteristics, it is necessary to find and identify new sources and new bacteria

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.