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

Abstract

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.

Statistical analysis of experimental factors for synthesis of copper oxide and tin oxide for antibacterial applications

“…Optimizing the synthesis of silver nanoparticles using the response surface methodology (RSM) and investigates the effects of various synthesis parameters on the size and stability of the nanoparticles. The most significant factors affecting the nanoparticle size were silver nitrate concentration and pH [32]. The response surface methodology to optimize the synthesis of iron oxide (Fe3O4) nanoparticles and investigated the effects of various synthesis parameters such as temperature, reaction time, and precursor concentration.…”

Copper-Treated Environmentally Friendly Antipathogenic Cotton Fabric with Modified Reactive Blue 4 Dye to Improve Its Antibacterial and Aesthetic Properties

“…The researchers have been utilizing various kinds of nanoparticles for the antimicrobial finishing of hospital textiles. Among them, the nanoparticles of TiO 2 , Cu, ZnO, Ag, MgO, Cu 2 O, CuO, etc., are the most prevalent and of specific interest [8][9][10][11]. The synthesis and applications of copper nanoparticles for the development of antimicrobial textiles have attracted a lot of attention in the past few years.…”

Response surface optimization of solvent tolerant cold active lipase production by Pseudomonas sp. VITCLP4

“…Among the current techniques utilized in optimization, experimental statistical techniques such as Plackett-Burman design (PB) and response surface methodology (RSM) are very effective in eliminating the limitations of single-factor optimization processes. [18] In this study, significant factors were screened by PB design, optimum levels of selected factors were evaluated by one-factor-at-a-time (OFAT) analysis, and the interactive effect of factors was analyzed by RSM. There are many reports on the process optimization of lipase from various sources [19][20][21]; the current work is the first one on medium optimization for a cold active lipase from Pseudomonas sp.…”