seyed ahmad dehdast

Green synthesis of nanoparticles is a safe and cost-effective process for creating nanoparticles using extracts from different parts of plants, such as flowers, leaves, stems, and roots. In this research, Melissa Officinalis L. (MO) aqueous extract was used for the synthesis of Selenium nanoparticles (Se NPs) for the first time. These extracts contain flavonoids, polyphenols, and alkaloids, which act as reducing agents in synthesizing nanoparticles. In this study, the extract serves both as a reducing agent and a capping agent during the fast and simple green synthesis of Selenium nanoparticles. The hydrodynamic size of the nanoparticles was investigated by using DLS. Further characterization of the shape and size of the nanoparticles was conducted through SEM and TEM studies. Moreover, the elemental composition of the NPs was identified through Energy Dispersive X-ray (EDX) elemental analysis. Microscopy analysis results showed that the Se NPs had a spherical shape. Furthermore, the particle size was determined to be 65 nm and 34 nm via DLS and SEM studies, respectively. Additionally, the biological evaluation of Se NPs demonstrated a non-toxic effect on the Human Umbilical Vein Endothelial Cells (HUVEC) normal cell line and anticancer activity on the MCF-7 breast cancer cell line.

The development of nanotechnology has proposed new routes in the design of the novel device for medical and biological applications. Tungsten disulfide (WS2) is a transition metal dichalcogenides. Tungsten disulfide nanomaterial (WS2 NM) are new nanostructures that can be used as a new option in bio-nanomedicine. Recently, Tungsten disulfide nanomaterial such as WS2 nanotubes, nanoparticles, quantum dots, and WS2 based nanocomposites have been used in some medical and biological science research. WS2 nanomaterial present chemical, physical, optical and electronic properties that can be exploited in a range of various applications. In this article, we discuss and report chemophysical relevant properties of tungsten disulfide nanostructures and the main achievements reached by using of this nanomaterial and related composite in biomedical research and biosensors, especially those involving electrochemical biosensors, optical biosensors, biomedical imaging, Photothermal therapy, radiotherapy, tissue engineering, and biocompatible anticancer and antibacterial agent.Keywords: Tungsten disulfide (WS2) Nanomaterial, Biosensor, Bio-imaging, Photothermal/Radiotherapy, Biocompatibility.

Leishmaniasis is a global disease that poses a threat to human life and is associated with complications. Current medications have limitations due to serious side effects, costs and drug resistance. Nanotechnology has received increased attention in recent years, owing to its extensive range of applications in various fields including parasitology and its inherent therapeutic properties. This study was designed to assess the effects of chitosan and chitosan-ZnO nanocomposite interventions on Leishmania major. In this study, different concentrations of the nanocomposite were prepared (200, 100, 50 and 25 µg/mL), the parasite was cultured at 24, 48 and 72 h intervals and the viability of promastigotes and nanocomposite toxicity were evaluated by MTT assay. IC50 was determined by counting parasites. The inhibitory effect of the chitosan and nanocomposite were compared with standard drugs using different concentrations. The IC50 for nanocomposite after 72 hours were 50 and 10 µg/mL for promastigotes and amastigotes, respectively. In addition, 15% toxicity of nanocomposite on macrophage cells was found. The MTT assay showed 18.54 % promastigote viability after 72 h exposure to 200 µg/mL concentration of nanocomposite. Results showed significant differences between treatment groups as compared to control groups. The above nanocomposites showed low toxicity and anti-leishmanial effects on both promastigote and amastigote forms. This study revealed anti-leishmanial activities of nanocomposites but further study is needed for in vivo evaluation of nanocomposites application for cutaneous leishmaniasis.

A thin layer of poly methylen green (PMG) was covered on glassy carbon (GC) electrode surface by electrochemical polymerization method. In the next step by dropping a suspension of carboxylic acid functionalized carbon nano-tubes on the PMG/GC electrode a layer of CNTs was coated on the electrode. Thereafter, to immobilize the enzyme on electrode surface, three layers of PMG, alcohol dehydrogenase and PMG were added to the modified electrode, respectively. The Fourier transform infrared, scanning electron microscopy and cyclic voltammetry measurements clearly confirmed the successful immobilization of enzyme on the GC electrode.