A new strategy to achieve high antimicrobial activity: green synthesised silver nanoparticle formulations with Galium aparine and Helichrysum arenarium.

Silver nanoparticles (AgNPs), which have recently gained attention due to their antimicrobial activity, can also be produced by green synthesis. The aims of this study were to (i) characterise green synthesized AgNPs using microwave-assisted aqueous extracts of Galium aparine (G-AgNPs) and Helichrysum arenarium (H-AgNPs) and (ii) investigate the combined antimicrobial effects of the G- and H-AgNPs in different ratios. Nanoparticle formation and reactions were determined with UV-Vis spectroscopy. The G-AgNPs were 52.0±10.9 nm in size, with a 0.285±0.034 polydispersity index (PDI), and a -17.9±0.9 mV zeta potential. For H-AgNPs these characteristics were 23.9±1.0 nm, 0.280±0.032, and -21.3±2.7 mV, respectively. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) confirmed that the particles were monodisperse and spherical. The Fourier transform-infrared spectroscopy (FT-IR) results showed the presence of reducing agents that stabilised the AgNPs. Three different nanoformulations (NF-1, NF-2, and NF-3) were prepared by combining these two synthesised nanoparticles in different ratios and their antimicrobial activity was tested against E. coli, S. aureus, C. albicans, and A. flavus. Our study is the first to show that combining AgNPs from two different biological sources can produce effective nanoformulations with improved antibacterial activity against E. coli and S. aureus. These nanoformulations showed lower minimum inhibitory concentrations (31.25 µg/mL against E. coli with all NFs; 62.5 µg/mL for NF-1 and 125 µg/mL for NF-2/3 against S. aureus) than G-AgNPs (62.5 µg/mL for E. coli) or H-AgNPs (125 µg/mL for S. aureus) alone. Their high combined inhibitory effect against E. coli (NF-1-3) was synergistic and against S. aureus (NF-2 and NF-3) potentially additive. Considering such promising results, we believe our study provides some direction for new research and strategies in antimicrobial therapeutics.

Selenium status in blood, urine, and hair samples of newly diagnosed pediatric cancer patients.

BACKGROUND/AIM: Selenium (Se) is a trace element that has multiple functions. Low Se amounts in serum and hair have been reported in pediatric and adult cancer patients. The aim of our study was to evaluate Se levels in the serum, urine, and hair of pediatric cancer patients with leukemia, lymphoma, and solid tumors when compared with healthy children. MATERIALS AND METHODS: The concentrations of Se in the serum, hair, and urine of 32 Turkish children as healthy controls and 88 Turkish children diagnosed with acute leukemia (58), lymphoma (16), and solid tumors (14) were measured using inductively coupled plasma mass spectroscopy. RESULTS: Se levels in the serum and hair of the children with cancer were significantly lower than those of the controls. There were no differences between the leukemia, lymphoma, and solid tumors group. On the other hand, the Se levels of the urine samples were slightly elevated in cancer patients compared with the control group. There was no marked difference in the Se levels of patients with different types of cancer. CONCLUSION: Se deficiency might be associated with the development of pediatric cancer. Especially in children, additional studies are needed to define whether low levels of Se may play a role in cancer pathogenesis.