Synthesis of Gold Nanotriangles and Silver Nanoparticles Using Aloe vera Plant Extract

Abstract

Biogenic gold nanotriangles and spherical silver nanoparticles were synthesized by a simple procedure using Aloe vera leaf extract as the reducing agent. This procedure offers control over the size of the gold nanotriangle and thereby a handle to tune their optical properties, particularly the position of the longitudinal surface plasmon resonance. The kinetics of gold nanotriangle formation was followed by UV-vis-NIR absorption spectroscopy and transmission electron microscopy (TEM). The effect of reducing agent concentration in the reaction mixture on the yield and size of the gold nanotriangles was studied using transmission electron microscopy. Monitoring the formation of gold nanotriangles as a function of time using TEM reveals that multiply twinned particles (MTPs) play an important role in the formation of gold nanotriangles. It is observed that the slow rate of the reaction along with the shape directing effect of the constituents of the extract are responsible for the formation of single crystalline gold nanotriangles. Reduction of silver ions by Aloe vera extract however, led to the formation of spherical silver nanoparticles of 15.2 nm +/- 4.2 nm size.

Catharanthus roseus: a natural source for the synthesis of silver nanoparticles

“…The SEM image showed relatively spherical shape nanoparticle formed with diameter range 48-67 nm. Similar phenomenon was reported by Chandran et al [17] .…”

“…The above synthetic protocol by plant extract or biomass exemplifies the promising application of the green synthesis of metal nanoparticles. Recent research reported that silver nanoparticles have been synthesized using various natural products like green tea (Camellia sinensis) [14] , neem (Azadirachta indica) leaf broth [15] , natural rubber [16] , Aloe vera plant extract [17] , latex of Jatropha curcas [1] , etc.…”

High yield synthesis of single-crystalline gold nanoplates using the metal ion-reducing bacteria

“…As a result, the shape-control agent can react with the generated gold nanoparticles more efficiently. The mechanism for gold nanoplate formation with lemongrass and Aloe vera extracts has been explained due to the presence of carbonyl groups which act as a shape-controlling agents adsorbing on selected facets of gold nuclei (11)(12)(13). To confirm the existence of such a shape-controlling agent in S. algae cell extract, FTIR analysis was performed (Figure 2).…”

“…Of recent interest is a low-cost and environmentally benign method for gold nanoplate synthesis using plant extracts to deposit gold metals by reducing gold ions in aqueous solution at room temperature. The Sastry group successfully prepared a gold nanoprism using plant extracts such as Cymbopogon flexuosus (lemongrass) (11) or Aloe vera (12). Excellent shape and selective formation of single crystalline triangular gold nanoparticles was observed.…”

Evaluation of plant-mediated Silver nanoparticles synthesis and its application in postharvest Physiology of cut Flowers

“…Recently, the potential of various plants for the synthesis of SNPs has been studied. Like pomegranate and Damask rose (Solgi and Taghizadeh 2012), rose (Dubey et al 2010a), banana (Bankar et al 2010), hibiscus (Philip 2010), geranium leaves (Shankar et al 2003), cinnamomum (Sathishkumar et al 2009), aloe (Chandran et al 2006), basil (Ahmad et al 2010) and tansy fruits (Dubey et al 2010b). Saffron (Crocus sativus) which is known as the world's most expensive spice is a bulbous perennial belonging to the iris family (Iridaceae) (Hosseinzadeh et al 2007).…”