In the present work, we studied the reduction of gold ions into gold nanoparticles using Nigella arvensis leaf extract in the one-step green synthesis method. The formation of N. arvensis gold nanoparticles (NA-GNPs) was confirmed by UV–Vis spectroscopy, XRD, FT-IR and TEM analyses. The XRD pattern confirmed the crystal structure of NA-GNPs, and TEM image showed the small size (3–37 nm) and almost spherical shape of NA-GNPs. NA-GNPs have not shown enhanced antioxidant properties compared to the plant extract while they were active against the clinical isolated bacterial strains. These nanoparticles showed the cytotoxicity effects against H1299 and MCF-7 cancer cell lines with an IC₅₀ value of 10 and 25 μg/ml, respectively. The extract of N. arvensis contained 212 μg/ml flavonoids and 145 μg/ml phenolic compounds. The contents of total phenolics and flavonoids of biosynthesized NA-GNPs were 68 and 189 μg/ml, respectively. Plant extract and NA-GNPs exhibited a maximum DPPH scavenging activity of 32% and 12%, respectively. The catalytic activity of NA-GNPs against methylene blue was 44%. In conclusion, these results suggest that NA-GNPs can act as a promising candidate for different medical applications produced by cost-effective, eco-friendly and straightforward green method.

In the current study, isoimperatorin, a natural furanocoumarin, is used as a reducing reagent to synthesize isoimperatorin mediated silver nanoparticles (Iso-AgNPs), and photocatalytic and electrocatalytic activities of Iso-AgNPs are evaluated. Iso-AgNPs consisted of spherically shaped particles with a size range of 79–200 nm and showed catalytic activity for the degradation (in high yields) of New Fuchsine (NF), Methylene Blue (MB), Erythrosine B (ER) and 4-chlorophenol (4-CP) under sunlight irradiation. Based on obtained results, Iso-AgNPs exhibited 96.5%, 96.0%, 92%, and 95% degradation rates for MB, NF, ER, and 4-CP, respectively. The electrochemical performance showed that the as-prepared Iso-AgNPs exhibited excellent electrocatalytic activity toward hydrogen peroxide (H₂O₂) reduction. It is worth noticing that the Iso-AgNPs were used as electrode materials without any binder. The sensor-based on binder-free Iso-AgNPs showed linearity from 0.1 µM to 4 mM with a detection limit of 0.036 μM for H₂O₂. This binder-free and straightforward strategy for electrode preparation by silver nanoparticles may provide an alternative technique for the development of other nanomaterials based on isoimperatorin under green conditions. Altogether, the application of isoimpratorin in the synthesis of nano-metallic electro and photocatalysts, especially silver nanoparticles, is a simple, cost-effective and efficient approach.

Human spaceflight has historically been managed by government agencies, such as in the NASA Twins Study¹, but new commercial spaceflight opportunities have opened spaceflight to a broader population. In 2021, the SpaceX Inspiration4 mission launched the first all-civilian crew to low Earth orbit, which included the youngest American astronaut (aged 29), new in-flight experimental technologies (handheld ultrasound imaging, smartwatch wearables and immune profiling), ocular alignment measurements and new protocols for in-depth, multi-omic molecular and cellular profiling. Here we report the primary findings from the 3-day spaceflight mission, which induced a broad range of physiological and stress responses, neurovestibular changes indexed by ocular misalignment, and altered neurocognitive functioning, some of which match those of long-term spaceflight², but almost all of which did not differ from baseline (pre-flight) after return to Earth. Overall, these preliminary civilian spaceflight data suggest that short-duration missions do not pose a significant health risk, and moreover present a rich opportunity to measure the earliest phases of adaptation to spaceflight in the human body at anatomical, cellular, physiological and cognitive levels. Finally, these methods and results lay the foundation for an open, rapidly expanding biomedical database for astronauts³, which can inform countermeasure development for both private and government-sponsored space missions.

In the present study, different effective parameters (temperature, reaction time, and pH) on the synthesis of quercetin‐assisted silver nanoparticles (QE‐AgNPs) are optimized. These biogenic NPs are characterized by different physico‐chemical analyses, including transmission electron microscopy, X‐ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and UV‐visible spectroscopy. In addition, the biological properties of QE‐AgNPs are evaluated through antioxidant, antimicrobial, anti‐inflammatory, hemolysis, and coagulation time assays. The formation of QE‐AgNPs is affected by different parameters. The optimum condition for the synthesis of QE‐AgNPs is attained at 70 °C and pH 7. Prepared QE‐AgNPs show a spherical shape with a crystalline nature and an average particle size of 20 ± 3.6 nm. The role of QE as a reducing and capping agent in the preparation process of QE‐AgNPs is demonstrated using FTIR analysis. These NPs with excellent antioxidant activity (82.3% at a concentration of 400 µg mL⁻¹) and anti‐inflammatory properties (82.5% and 100% at concentrations of 37.25 and 500 µg mL⁻¹, respectively), show good antimicrobial effects, particularly against Staphylococcus aureus. Furthermore, the results of the hemolytic and coagulation assay of QE‐AgNPs indicate their hemo‐compatibility. Therefore, hemo/bio‐compatible QE‐AgNPs with excellent and unique properties can be employed in different medicinal and pharmacological applications.