Bioinspired morphology-controlled silver nanoparticles for antimicrobial application

Phytochemicals sources have been extensively used as reducing and capping agents for synthesis of nanoparticles (NPs). However, morphology-controlled synthesis and shape/size dependent applications of these NPs still need to be explored further, and there is a need to develop a way in which particular and optimized phytochemicals result in the desired NPs in lesser time and cost with higher reproducibility rate. The present study is focused on morphology-controlled synthesis and shape/size dependent application of silver NPs based on the fractionated phytochemicals of Elaeagnus umbellata extract (EU). Unlike other approaches, in this study the reaction parameters such as time, temperature, pH, stirring speed and concentration of the precursor solutions were not altered during the optimization process. The fractionated phytochemicals were used separately for the synthesis of AgNPs, and the synthesized NPs were characterized by UV-visible, FT-IR, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Our findings suggested that the constituents of the extract fractions varied with the selection of the extraction solvent, and the shape/size, bactericidal properties and toxicity of the NPs have a strong correlation with the phytochemicals of the plant extract. The fractionated phytochemicals present in the water fractions (EUW) resulted in monodispersed spherical AgNPs in the size about 40 nm. The NPs have significant stability in physiological conditions (i.e. temperature, pH and salt), have good antibacterial activity, and were found to be non-toxic. Furthermore, AFM and SEM analysis exposed that the NPs killed the bacteria by disturbing the cellular morphology and releasing the cellular matrix. Our results justify the use of different fractions of plant extract to obtain detail implications on shape, size, antibacterial potential and toxicity of AgNPs. This is the first step in a controllable, easy and cheap approach for the synthesis of highly stable, uniform, non-toxic and bactericidal AgNPs using five fractions of EU. The findings suggested that the synthesized NPs, particularly from EUW, could be used in pharmaceutical and homeopathic industry for the development of antibacterial medications.