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Biosynthesized silver nanoparticles (AgNPs) are widely used in varied applications, which are morphology dependent. Consequently, a morphology-controlled synthesis is mandatory. Although there are several studies focused on the plant extract-based biosynthesis of metallic nanoparticles, the use of extracts obtained from agro-wastes is scant. Furthermore, information regarding morphology modification through the use of additional agents is even more scarce. Thus, in this study, AgNPs were synthesized using a malt extract (ME) obtained from an artisanal beer brewing process residue. Additionally, sodium chloride (NaCl), gum arabic (GA), and talc (T) were used in an attempt to modify the morphology of AgNPs. XRD, DLS, SEM, and TEM results demonstrate that stable AgNPs of different sizes and shapes were synthesized. FTIR, HPLC analysis, and the quantification of total proteins, free amino acids, reducing sugars, and total polyphenols before and after AgNPs synthesis showed that ME biomolecules allowed them to act as a source of reducing and stabilizing agents. Therefore, this study provides evidence that ME can be successfully used to biosynthesize AgNPs. Additionally, the antibacterial activity of AgNPs against Gram-negative and Gram-positive bacteria was evaluated. Results indicate that AgNPs show a higher antibacterial activity against Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

Agave tequilana Weber var. azul fibers (ATF) are widely used as a reinforcement material despite their polarity makes them incompatible with hydrophobic matrices. Consequently, ATF are commonly modified employing different chemical processes (e.g., mercerization and coupling agents) to change their surface characteristics to improve the interface between the fibers and the polymeric matrix. Nevertheless, these treatments could damage the fibers during the process, negatively affecting their natural properties. The use of nanotechnology to repair this natural material could help to restore its intrinsic properties and give it new ones as antibacterial activity. In this work, chemically treated ATF were used as templates for the biosynthesis of silver nanoparticles (AgNPs) using a natural extract obtained from Agave tequilana Weber var. azul leaves (ATL) as reducing agent. Scanning and transmission electron microscopy images as well as dynamic light scattering results indicate that stable nanometric particles were successfully synthesized on all fibers. X-ray photoelectron spectroscopy and X-ray diffraction results confirm the composition of the nanoparticles. Tensile tests indicate that AgNPs improved the mechanical properties of fibers previously mercerized and treated with maleic anhydride grafted polyethylene as coupling agent. Additionally, an antibacterial effect against S. enterica was conferred to ATF due to the presence of AgNPs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • AgNs have been synthesized by a green method to improve charge transport in an OSC. • PFN:AgNs mix was used as electron transport layer. • PCE increases due to the use of AgNs. Abstract Low power conversion efficiency represents the main drawback of organic solar cells (OSC) compared to inorganic devices. Therefore, a novel bulk electron transport layer of silver nanostructures (AgNs) inside poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] is proposed to be used in OSC. Different concentrations (i.e. 5 and 10% v/v) of AgNs synthesized with a natural extract of Agave tequilana Weber var. Azul as reducing agent were used to improve the performance of the photovoltaic devices. Due to the presence of AgNs, which promote better charge transport, an improvement from 7.04 to 32.16% of the overall performance of the OSC was observed compared to the reference device without nanostructures. [ABSTRACT FROM AUTHOR]