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<p>There is a continuing need for the development of new pesticides to combat some of the harmful pests. The proposed nano-silver based agent will offer an effective pest management. It would be a non-toxic, safe and improved weapon to combat pests, and would have significant impact on the economic costs. Our proposed studies have realistic possibilities to produce major advances toward the development of a silver nanoparticle (AgNP)-based pesticide for agricultural applications capable of delivering a high dose of pesticide load to the desired plants. The specific objectives of our proposal will be focused on understanding the toxicity of silver nanoparticles in various biological matrices. </p>
<p>Specific Objective 1- To optimize synthetic protocols for the synthesis of silver nanoparticles and their utility toward the production of nanoparticulate constructs via
bioconjugation with proteins, baculoviruses, and eicosanoids for specifically targeted pest insect control. </p>
<p>Specific Objective 2- To conduct in vitro studies of silver nanoparticles and nanoconstructs derived from carbohydrates and peptide/protein biomolecules. Studies will include in vitro analysis of simulated silver nanoconstructs to gain insights on modes and rates of leaching of silver nanoparticles from a biomolecular matrix and nanoconstructs. </p>
<p>Specific Objective 3- Surface analysis and mechanism of interactions of AgNPs embedded stabilized with carbohydrates within nanoparticuclate constructs with cellular components. </p>
<p>Specific Objective 4- To investigate the toxicity of silver nanoparticles on insects relevant to pesticidal applications. The proposed research will be performed over a three-year period starting September 2011 and will be administered through Lincoln University and
with collaboration from University of Missouri-Columbia (UMC) and USDA agents at the Agricultural Research Service (ARS) Biocontrol of Insects Research Laboratory near the UMC campus. The following outcomes are expected from the proposed project: </p>
<p>1. A method to synthesize different sizes of nanoparticles encapsulated in biological matrices with detailed toxicity characteristics. </p>
<p>2. Detailed toxicity profile of silver nanoparticles with respect to non-targeted pests. </p>
<p>3.The development of a set of nanoparticles with which to treat harmful pests or pesticide resistant microbes present in plants. </p>
<p>The overall goal of the project is focused on developing a silver nanoplatform that is encapsulated in a biomolecular platform. In particular, the project goals will center on the utilization of silver nanoparticles and analyze their toxicity. The proposed project mainly addresses the Program
Priority Area of Sustainable Agriculture. However, the Priority Areas of Food Safety, Water Quality, and Global Climate Change will also benefit from the proposed research. Studies and Experimentation in Food and Agricultural Sciences is the NIFA Program Need Area targeted by the presented research.</p>
<p>NON-TECHNICAL SUMMARY:<br/> Silver nanoparticles have received significant attention as pesticide for agricultural applications in the past few years. It is quite relevant as there is a growing increase in the number of pests exhibiting resistance to existing chemical pesticides. Utility of silver nanoparticles as an efficient pesticide would become a reality if the nano-community possessed the tools and agents to understand the toxicity of these nanoparticles. The proposed research within the award mechanism will address this compelling need. The specific objectives of our proposal encompass the development of new agents for understanding the toxicity relevant to agricultural use, using nanotechnology principles that are directly relevant to the overall outcomes sought within the current award mechanism. 1-One of the major challenges is to develop accurate simulated
nanoparticles in a biomolecular matrix without destroying the biological property of the matrix. It is important to recognize that AgNPs for agricultural use will encounter biomolecules and phytochemicals present in plants. Currently available synthetic methods fail to synthesize AgNPs of desired size in any desired biological matrix. Thus, the understanding of toxicity of AgNPs has been largely not pursued. 2-Literature available on toxicity data is mainly derived from either organic stabilized AgNPs or non-biomolecular matrix encapsulated AgNPs. The widely used AgNPs include surfactant or organic ligand stabilized nanoparticles. Limitations in this data have been emphasized by scientists as well as EPA and FDA agencies. There is a compelling environmental need for developing a synthetic method for developing AgNPs encapsulated in plant based biomolecules. 3-Currently there is no clear
understanding about the fate of non-target pests upon interaction with AgNPs. If AgNPs prove to be harmful to non-targeted pests, then the surface needs to be modified to make them non-toxic. There is general consensus within the nanotechnology community that understanding the toxicity of AgNPs present in biomatrix contributes decisively to the utilization of AgNPs for agricultural applications. Based on the above challenges, it is imperative to develop the following tools to provide an opportunity for nanotechnology to serve in the agricultural arena: (i) a synthetic method to encapsulate different sizes of AgNPs in biologically relevant matrices; (ii) a method to analyze the stability of AgNPs; and (iii) toxicity of resulting AgNPs in cellular lines. A solution for the above important factors would be ideal to overcome the current challenges faced by the nanotechnology community.
<p>APPROACH:<br/> To achieve the objectives of this proposal 1-We will synthesize a library of AgNPs with different sizes (2, 3, 5, 7, 8 and 10 nm) and utilize them for the construction of nanoparticulate constructs and simulated nanomaterials via conjugations with biomolecules. Studies will include direct generation of AgNPs in biomolecules, and complete characterization of nanoconstructs using analytical techniques, such as AFM, TEM, and SEM. 2- In vitro studies of silver nanoparticulates including those derived from various biomolecules such as carbohydrates and Gum Arabic protein matrix will be examined by direct interaction of nanoparticulate constructs with serum proteins, bovine serum albumin (BSA), human serum albumin (HSA), and mammalian blood samples. UV-visible absorption and TEM images will be recorded to determine the extent of interaction of AgNPs with
biological fluids and proteins. 3-We will investigate the interactions of AgNPs with healthy cells by detailed analysis using TEM, SEM and AFM. 4-Although there has been increased use of AgNPs in recent years, little is known concerning their environmental impact. It is unknown if they are toxic to invertebrates after acute or long-term exposure. To address this deficiency, baseline impact of silver nanoparticle ingestion on both pest and non-target insects will be examined over multiple generations. The project will be evaluated through three crucial factors: a) educational, b) intellectual, and c) capacity building at Lincoln University. During the course of the project, test results will be collected, analyzed and disseminated through presentations at conferences, journal publications, and extension bulletins.
<p>PROGRESS: 2012/09 TO 2013/08<br/>Target Audience: Scientific community Pesticidal industry Farmers growing different agricultural products Students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? PI and Co-PIs have been mentoring two graduate students and 3 undergraduate students in this project. The students are receiving professional training on synthesis and characterization of different nanoparticles and characterization. Students have been trained on operating state of the art instrumentations. PI and Co-PIs constantly are engaged in designing and development of new synthesis methods as well as testing protocols, which indeed results in professional growth in the field. The study is performed over multiple generations of the insects and during this reporting period data has been collected
and manuscripts are under preparation. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Planning on synthetic protocols for the synthesis of silver nanoparticles and their utility toward the production of nanoparticulate constructs via bioconjugation with proteins, baculoviruses, and eicosanoids for specifically targeted pest insect control
<p>PROGRESS: 2011/09/01 TO 2012/08/31<br/>OUTPUTS: The overall goal of the project is focused on developing a nanoparticle-based agent that is encapsulated in an environmentally compatible platform for pesticide applications. The main objective is towards utilization of silver nanoparticles as pesticides, or as a carrier agent of biopesticides, and to analyze their toxicity. We will synthesize and utilize well characterized nanoparticulate constructs of silver to evaluate the pesticide and toxicity effects. Detailed in vitro investigations on plant cells are planned to understand the mechanistic aspects of pesticide implications. The effect of nanoparticles on representative predator and beneficial insects will also be compared to understand the detailed pesticide and toxicity effects of three silver nano constructs. A comprehensive knowledge of the toxicological impact
of the silver nanoconstructs towards food, water and environmental safety will also be studied. Our first step was to synthesize nanoparticles of similar size with different surface coatings. Any dissimilarity in the toxicity was due to the change in the surface coating and not because of the size. We synthesized silver nanoparticles coated with polysaccharide (NP-1 size 5-8 nm) and oligosaccharide chains (NP-2 size 5-8 nm). Detailed characterization using conventional spectroscopic and electron-microscopy confirmed the sizes are between 5-8 nm. Zeta potential and hydrodynamic volume parameters were also measured and documented. Stability of NPs 1-2 under farming conditions (high or low pH, salt content variations, and in high-dilution conditions) were studied. NPs 1-2 were fed to pest and predator insects and the effect on the developmental stages were monitored We monitored the effect
of the two synthesized silver nanoparticles on pests and beneficial insects (predators) before unraveling their applications as pesticide. We have chosen two representative insects: The agricultural pest, Heliothis virescens (Tobacco bud worm), and a non-target hemipteran generalist predator, a beneficial insect, Podisus maculiventris (spined soldier bug). We have substantial knowledge on the basic biology and life history parameters of these insects making studies on the response of these insects to nanoparticles possible. The development and mortality of the pests and predators were monitored in different life stages by feeding the nanoparticles to the insects. In this study, the insects were fed different concentrations of both nanoparticles in their artificial diets. On September 2012 this study was presented at USDA-NIFA PD conference at Alabama. PARTICIPANTS: Dr. Zahra
Afrasiabi(PI) and Dr. Frieda Eivazi (Co-PI) are working with University of Missouri Columbia on Differenet stages of this project. Marang Mathiba (undergraduate student) and Kristin Finley (graduate student) assisted PI with progress of the project. Dr. Raghuraman Kannan (University of Missouri-Columbia) and Dr. Holly Popham (USDA-ARS-Columbia) are the collaborators of this project. TARGET AUDIENCES: 1-scientific community: The toxicology studies of silver nanoparticle-based pesticides will be presented in relevant national and international conferences and published in scientific journal papers. The findings of our studies will be valuable and beneficial to the scientific community. 2-farmers: the ultimate beneficiary of this project will the farmers who will have a clear idea on efficacy of silver nanoparticles as pesticides. PROJECT MODIFICATIONS: Nothing significant to report during
this reporting period.