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• AgNPs were green synthesized using leaf extracts of P. boldus and incorporated into an nPSi structure by capillary suction. • Composite thin films of nPSi/AgNPs were chemically and morphologically characterized. • Antibacterial activity of nPSi/AgNPs layers was successfully evaluated using a wide fan of bacterial strains. This work is about the fabrication of composite thin films of nanoporous silicon/green synthesized silver nanoparticles and their potential use as antibacterial surfaces. To obtain the composite layers, silver nanoparticles were synthesized using leaf extracts of P. boldus , and subsequently integrated on nanoporous silicon matrix. The achieved samples were characterized microscopically (TEM and AFM), and physiochemically (UV–vis spectroscopy, LIBS, and XRD). Moreover, the antibacterial activity of the composite layers was studied using different strains of Gram-positive (S. aureus and S. epidermidis) and Gram-negative (K. pneumoniae , E. coli , and P. aeruginosa) bacteria. The experimental results showed the potential of these composite thin films as antibacterial surfaces for biomedical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel biosynthesis of silver nanoparticles (AgNPs) was formed by the phage. • The AgNPs depended mainly on phage's negatively-charged capsid proteins. • The AgNPs resulted in a uniform particles with a size ranging from 10 to 30 nm. • The biosynthesis AgNPs had shown a promising antibacterial and antibiofilm activity. • The AgNPs showed highly specific and rapid detection for cadmium in water. The risk of multidrug-resistant bacteria and heavy metals contaminating the environment raises a drastic public issue. In this report, we succeeded in introducing a novel synthesis technique of silver nanoparticles (AgNPs) with antibacterial, anti-biofilm activities and detection of cadmium in water. Furthermore, we managed to reduce silver nitrate (AgNO 3) using the capsid structural proteins of bacteriophage, a naturally occurring bacterial virus. The formulated AgNPs were regular in shape and ranged from 10 to 30 nm in size, as indicated from the transmission electron micrographs (TEM). Moreover, the formulated AgNPs highlighted biofilm deformation capabilities against the model bacteria, Staphylococcus sciuri. Furthermore, the newly synthesized AgNPs can rapidly sense the heavy metal in a concentration of 100 µM. Thus, this study reveals the outstanding ability of the bacteriophage-mediated synthesis of AgNPs and suggests its promising activity over the traditional synthesis methods. [ABSTRACT FROM AUTHOR]

• The antimicrobial properties of AgNPs are affected by their size. • The viscosity of the reaction system and size of crystal growth space affect AgNPs size. • Preparing AgNPs by using N -maleoyl chitosan and montmorillonite. • Higher antibacterial ability and lower cytotoxicity. The antimicrobial properties of silver nanoparticles (AgNPs) are significantly affected by their size. In our previous study, we synthesized low-toxicity AgNPs using chitosan derivatives. As chemical reductants and stabilizers were not used in the preparation process, the toxicity of the products was very low. However, the size of the as-obtained nanoparticles was relatively large (100–150 nm). In this study, we used N -maleoyl chitosan and montmorillonite to prepare small-sized green AgNPs and investigated the effect of the reaction system viscosity and crystal growth space on the formation of small-sized nanoparticles. We found that increasing the viscosity of the reaction system or controlling the crystal growth space was conducive to the green preparation of small-sized AgNPs. The prepared AgNPs had higher antibacterial ability and lower cytotoxicity. To the best of our knowledge, this is the first time that AgNPs with such a small size (less than 5 nm) have been prepared using a simple and completely green method. [ABSTRACT FROM AUTHOR]

[Display omitted] • AgNPs were facile synthesized from Glochidion candolleanum leaf (GCL) extract. • FT-IR, FE-SEM, and TEM analyses confirmed the properties of AgNPs. • GCL·AgNPs exhibited antimicrobial activity against G+ve and G−ve bacteria. • GC–MS revealed the presence of antimicrobial phytochemicals in GCL extract. In the present study, Glochidion candolleanum (Wight & Arn.) Chakrab. & M. Gangop. leaf (GCL)-ethyl acetate extract was used for the phytosynthesis of silver nanoparticles (AgNPs) and subjected to antibacterial assay with G+ve and G−ve bacteria. The GCL·AgNPs synthesized were characterized through various spectroscopic and microscopic analyses, while the phytochemical compounds was analyzed by GC–MS. The discrete GCL·AgNPs formed were micron-scale range. TEM images of AgNPs reveal that nanoparticles were spherical and ellipsoidal in shape, dispersed uniformly and capped with secondary material of ≈10 nm thickness. A maximum inhibition zone of 12.2 mm diameter was observed against Salmonella enterica followed by 11.8 mm diameter against Pseudomonas aeruginosa. GC–MS analysis revealed the occurrence of bioactive phytocompounds in GCL extract, hexamethylcyclotrisiloxane, 2,4,6-cycloheptatrien, benzenepropanoic acid, 2-ethylacridine, benzo[h]quinoline, methyltris(trimethylsiloxy)silane and 5-methyl-2-phenylindolizine. The findings suggest that GCL could be used for developing antibacterial AgNPs against pathogenic bacteria. [ABSTRACT FROM AUTHOR]

[Display omitted] • AgNPs are bio-synthesized using Acacia etbaica valve extract. • This method was very fast, simple and environmental friendly. • Antimicrobial activity against human pathogenic microbes was efficaciously investigated. • AgNPs are not effective against E. Faecalis and P. aeruginosa. • The prepared AgNPs are more potent against specific microbe than their crude extract. Here, we employed green and very fast (clock) synthesis of silver nanoparticles (AgNPs) by means of silver nitrate and Acacia etbaica valve extract at room temperature. Transmission electron microscopy (TEM) results confirm the spherical shape and diameter (size) ranging from 6.38 ± 3.21, 10.09 ± 3.21 and 20 ± 3.21 for AeAg-1, AeAg-2 and AeAg-3, respectively. TEM results showed that size of AgNPs increase as the concentration of AgNO 3 decreases due to the low concentration of bio reducing agent present in the extract. The enhanced antimicrobial activity against human pathogenic microbes was investigated by diffusion method based on zone of inhibition. The prepared AgNPs showed high specificity against the tested pathogens, namely K. pneumonia , S. typhi , S. dysenteriae , P. mirabilis , S. saprophyticus , S. aureus and C. albican with inhibition zone between 22.3 ± 2.08 mm and 11.67 ± 1.15 mm. On the other hand, the prepared AgNPs did not exhibit high specifity against E. Faecalis and P. aeruginosa. Therefore, it can be concluded that the prepared AgNPs have potential as natural antimicrobial agents against microbes with multidrug resistance. [ABSTRACT FROM AUTHOR]