Phytosynthesis of intracellular and extracellular gold nanoparticles by living peanut plant (Arachis hypogaea L.)

Abstract

Inorganic nanomaterials of different chemical compositions are conventionally synthesized under harsh environments such as extremes of temperature, pressure, and pH. Moreover, these methods are eco-unfriendly and cumbersome, yield bigger particles, and agglomerate because of not being capped by capping agents. In contrast, biological synthesis of inorganic nanomaterials occurs under ambient conditions, namely room temperature, atmospheric pressure, and physiological pH. These methods are reliable, eco-friendly, and cheap. In this paper, we report for the first time the extracellular and intracellular synthesis of gold nanoparticles (GNPs) using living peanut seedlings. The formed GNPs were highly stable in solution and inside the plant tissue. Transmission electron microscopy revealed that extracellular GNPs distributions were in the form of monodispersed nanoparticles. The nanoparticles ranged from 4 to 6 nm in size. The intercellular nanoparticles were of oval shape and size ranged from 5 to 50 nm. Both extracellular and intracellular nanoparticles were further characterized by standard techniques. The formed GNPs inside the plant tissue were estimated by inductively coupled plasma spectrometry. This opens up an exciting possibility of a plant-based nanoparticle synthesis strategy, wherein the nanoparticles may be entrapped in the biomass in the form of a film or produced in the solution, both of which have interesting applications.

Extracellular synthesis of silver nanoparticles using living peanut seedling

“…Here, we show the change in the colour of the root to light brown colour. In earlier reports in A. hypogaea (peanut) (Raju et al 2012) and Sesbania too, the colour of roots changed to purple when they synthesized intracellular gold nanoparticles and also confirmed the presence of intracellular nanoparticles (Sharma et al 2007). …”

“…In previous report, the synthesis of gold nanoparticles with living peanut seedling has been demonstrated, where it was suggested that some of the proteins and phenolics leached from the roots helped in the formation of GNPs (Raju et al 2012). Possibly these factors might have played role in the reduction of silver nanoparticles also.…”

“…Biological synthesis of nanoparticles using microorganisms (Klaus et al 1999;Konishi et al 2007;Nair and Pradeep 2002), enzyme (Willner et al 2006) and plants or plant extracts (Shankar et al 2004;Raju et al 2011Raju et al , 2012Raju et al , 2013a has been suggested as possible alternative ecofriendly method.…”

“…The formation of stable intracellular gold nanoparticles by Sesbania seedlings has been reported (Sharma et al 2007). We have earlier reported the synthesis of extra-and intracellular gold nanoparticles by peanut and its callus cells (Raju et al 2012(Raju et al , 2013a. Synthesis of nanoparticles by plant can be advantageous over other biological methods by eliminating the lengthy process of maintaining cell cultures (Shankar et al 2004).…”

Exogenous Production of Silver Nanoparticles by Tephrosia apollinea Living Plants under Drought Stress and Their Antimicrobial Activities

“…These methods are considered more cost-effective, safe, and eco-friendly [7]. In addition, they require ambient conditions like room temperature, atmospheric pressure, and physiological pH [8]. Among biological systems, living plants are renewable, safe to handle and easily available resources for nanoparticle production [1].…”