Physical and Mechanical Characterization of a Functionalized Cotton Fabric with Nanocomposite Based on Silver Nanoparticles and Carboxymethyl Chitosan Using Green Chemistry

Plackett-Burman design in the biosynthesis of silver nanoparticles with Mutisia acuminatta (Chinchircoma) and preliminary evaluation of its antibacterial activity

Background: The aim of this study was to synthesize silver nanoparticles (AgNPs) using the methanolic fraction of Mutisia acuminatta leaves using Plackett-Burman design to optimize process parameters and to evaluate its antibacterial effect. Methods: For the separation of Mutisia acuminatta phytoconstituents, chromatographic techniques were used. For characterization and identification, UV - VIS spectrophotometry, FTIR spectrophotometry, Dynamic Light Scattering (DLS) and transmission electron microscopy (TEM) were used. The Plackett-Burman design used polynomial regression statistical analysis to determine the most influential variables. Results: UV-VIS spectroscopy reported an absorbance concerning surface plasmon resonance between 410-420 nm wavelength for the AgNPs. FTIR spectrophotometry reported characteristic peaks in the biosynthesized AgNPs, observing the disappearance of spectral peaks between 1000-1500 cm -1. By UHPLC-MS, caffeic acid derivatives, coumarins, flavonoids, lignans, disaccharide and a complex formed between silver and the solvent (AgCH3CN+) were identified. Using DLS, the AgNPs presented an average hydrodynamic size of 45.91 nm. TEM determined the spherical shape of the AgNPs, presenting diameters in the range of 30 to 60 nm. The biosynthesized AgNPs showed higher antibacterial activity against Escherichia coli and Staphylococcus aureus than the total extract, the methanolic fraction and pure methanol. The polynomial model in the biosynthesis was validated with an adequate fitting representing the experimental data of the process. The most significant variables for the model obtained were the reaction pH (X 2) and the concentration of the precursor salt AgNO 3 (X 6). Conclusions: The synthesized AgNPs offer a viable option for further development due to the presence of bioactive compounds, adequate characterization and antibacterial activity.

Bibliometric Analysis of Current Status of Circular Economy during 2012–2021: Case of Foods

Food is usually recognized as a limited resource in sustainability, recognized by the United Nations (UN) Sustainable Development Goal (SDG) 2, which aims to achieve zero hunger. It is expected that the circular economy (CE) can improve processes related to food production. The objective of the present study was to apply a bibliometric approach using VOSviewer visualization software as a research tool to analyze the relevant literature from the Scopus database in the field of circular economy and its relation to improvements in food issues throughout 2012–2021. A total of 1316 articles were analyzed. Italy was the most productive country with 313 articles, with Wageningen University & Research the organization with the most publications with 39 articles. The top 10 institutions originated from Italy, The Netherlands, France, and Denmark. Sustainability was the most productive journal with 107 articles. Bioresource Technology had the highest average citation frequency (44.68). The study helps initiate investigations to adapt the results obtained and create new strategies for increasing food circular economy efforts.

Optimization of Synthesis of Silver Nanoparticles Conjugated with Lepechinia meyenii (Salvia) Using Plackett-Burman Design and Response Surface Methodology—Preliminary Antibacterial Activity

In the present investigation, an ethanolic fraction (EF) of Lepechinia meyenii (salvia) was prepared and fractionated by gradient column chromatography, and the main secondary metabolites present in the EF were identified by HPLC-MS. Silver nanoparticles (AgNPs) were synthesized and conjugated with the EF of Lepechinia meyenii (salvia). The AgNPs synthesis was optimized using Plackett-Burman design and response surface methodology (RSM), considering the following independent variables: stirring speed, synthesis pH, synthesis time, synthesis temperature and EF volume. The AgNPs synthesized under the optimized conditions were characterized by UV visible spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM). The antibacterial activity of the AgNPs against Staphylococcus aureus (ATCC® 25923) was evaluated. The following flavonoids were identified: rosmarinic acid, diosmin and hesperetin-7-O-rutinoside. The optimized conditions for the synthesis of nanoparticles were pH 9.45, temperature 49.8 °C, volume of ethanolic fraction 152.6 µL and a reaction time of 213.2 min. The obtained AgNPs exhibited an average size of 43.71 nm and a resonance plasmon of 410–420 nm. Using FT-IR spectroscopy, the disappearance of the peaks between 626.50 and 1379.54 cm−1 was evident with the AgNPs, which would indicate the participation of these functional groups in the synthesis and protection of the nanoparticles. A hydrodynamic size of 47.6 nm was obtained by DLS, while a size of 40–60 nm was determined by STEM. The synthesized AgNPs conjugated with the EF showed a higher antibacterial activity than the EF alone. These results demonstrate that the AgNPs synthesized under optimized conditions conjugated with the EF of the Lepechinia meyenii (salvia) presented an increased antibacterial activity.

Green Synthesis of a Novel Silver Nanoparticle Conjugated with Thelypteris glandulosolanosa (Raqui-Raqui): Preliminary Characterization and Anticancer Activity

In the last decade, the green synthesis of nanoparticles has had a prominent role in scientific research for industrial and biomedical applications. In this current study, silver nitrate (AgNO3) was reduced and stabilized with an aqueous extract of Thelypteris glandulosolanosa (Raqui-raqui), forming silver nanoparticles (AgNPs-RR). UV-vis spectrophotometry, dynamic light scattering (DLS), and scanning transmission electron microscopy (STEM) were utilized to analyze the structures of AgNPs-RR. The results from this analysis showed a characteristic peak at 420 nm and a mean hydrodynamic size equal to 39.16 nm, while the STEM revealed a size distribution of 6.64–51.00 nm with an average diameter of 31.45 nm. Cellular cytotoxicity assays using MCF-7 (ATCC® HTB-22™, mammary gland breast), A549 (ATCC® CCL-185, lung epithelial carcinoma), and L929 (ATCC® CCL-1, subcutaneous connective tissue of Mus musculus) demonstrated over 42.70% of MCF-7, 59.24% of A549, and 8.80% of L929 cells had cell death after 48 h showing that this nanoparticle is more selective to disrupt neoplastic than non-cancerous cells and may be further developed into an effective strategy for breast and lung cancer treatment. These results demonstrate that the nanoparticle surfaces developed are complex, have lower contact angles, and have excellent scratch and wear resistance.