Colloids and Surfaces B: Biointerfaces 92 (2012) 209–212 Contents lists available at SciVerse ScienceDirect Colloids and Surfaces B: Biointerfaces jou rn al h om epage: www.elsevier.com/locate/colsurfb Acaricidal, insecticidal, and larvicidal efficacy of aqueous extract of Annona squamosa L peel as biomaterial for the reduction of palladium salts into nanoparticles Selvaraj Mohana Roopan a,∗ , Annadurai Bharathi a , Rajendran Kumar b , Venkatesh Gopiesh Khanna b , Arunachalam Prabhakarn c a Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu, India b Division of Biomolecules and Genetics, School of Biosciences & Technology, VIT University, Vellore 632 014, Tamil Nadu, India c National Institute of Technology, Trichirapalli 620 015, Tamil Nadu, India a r t i c l e i n f o Article history: Received 24 October 2011 Received in revised form 22 November 2011 Accepted 23 November 2011 Available online 6 December 2011 Keywords: Biosynthesis Annona squamosa L peel Palladium Nanoparticles a b s t r a c t In recent years the utilization of secondary metabolites from plant extract has emerged as a novel technology for the synthesis of various nanoparticles. In this paper we studied the potential of nanocrys- talline palladium nanoparticles production using acaricidal, insecticidal and larvicidal efficacy of Annona squamosa L aqueous peel extract as the biomaterial for the first time. The synthesized nanoparticles were characterized and confirmed as palladium nanoparticles by using UV–visible spectroscopy, XRD and TEM analysis. The results clearly showed that the compounds containing OH as a functional group played a critical role in capping the nanoparticles. Also the results highlight the possibility of green pathways to produce palladium nanoparticles. © 2011 Elsevier B.V. All rights reserved. 1. Introduction In modern nanotechnology, eco-friendly nanoparticles produc- tion methods are gaining importance because of the reduction of toxic chemical usage. Now-a-days silver, platinum, gold and palladium metal nanoparticles have tremendous applications in heterogeneous and homogeneous catalysis, optoelectronics, diag- nostic biological probes and display devices [1]. Annona squamosa L. (Annonaceae) is well known for its edible tropical fruits, custard apple and mostly distributed in America and Asia. It is reported that this plant possess several medicinal properties [2–4] such as cardiotonic and insecticidal activity etc. In nanoparticles preparation the researcher started to use various sources to control nanoparticles shape and size. There is an increas- ing interest in the biosynthesis of palladium nanoparticles using plants and microorganisms. In recent years, the bioreduction of noble metallic species using microorganisms has generated more interest among researchers around the world [5]. To synthesize pal- ladium nanoparticles sulphate reducing bacterium Desulfovibrio desulfuricans NCIMB 8307 has been used [6]. But the commercial ∗ Corresponding author. Tel.: +91 09865610356. E-mail address: mohanaroopan.s@gmail.com (S.M. Roopan). synthesis of metal nanoparticles at industrial scale is unfeasible using microbes as it requires stringent operational conditions and skilled professional. The reduction rate of metal ions by plants has been found to be much faster than the microorganisms. Fur- ther the extracellular nanoparticles synthesis using plant extracts would be economical owing to easier downstream processing [7]. Recent findings showed that palladium nanoparticles were syn- thesized in bulk quantities using coffee and tea extract at room temperature without using surfactant, capping agent and template [8]. Many research groups have been reported the palladium syn- thesis using various secondary metabolism which is present in the plant of Cinnamon zeylanicum bark [9], Curcuma longa tuber [10]. In this paper, for the first time we studied the potential of nanocrystalline palladium nanoparticles production using agricul- tural waste A. squamosa L aqueous peel extract as the biomaterial. 2. Materials and methods 2.1. Plant material A. squamosa fruits were collected from in and around Melvisharam (12 ◦ 56 ′ 23 ′′ N, 79 ◦ 14 ′ 23 ′′ E), Vellore district, Tamil Nadu, India. The taxonomic identification was made by Dr. B. Annadurai, Department of Plant Biology and Biotechnology, C. 0927-7765/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2011.11.044