Source: LINCOLN UNIVERSITY submitted to
SILVER NANOPARTICLES AS PESTICIDE FOR AGRICULTURAL APPLICATIONS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
0226333
Grant No.
2011-38821-31034
Project No.
MOX-AFRASIABI3
Proposal No.
2011-02535
Multistate No.
(N/A)
Program Code
EQ
Project Start Date
Sep 1, 2011
Project End Date
Aug 31, 2015
Grant Year
2011
Project Director
Afrasiabi Navan, Z.
Recipient Organization
LINCOLN UNIVERSITY
(N/A)
JEFFERSON CITY,MO 65101
Performing Department
Agriculture
Non Technical Summary
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.
Animal Health Component
(N/A)
Research Effort Categories
Basic
30%
Applied
30%
Developmental
40%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2165220113050%
2165220200050%
Knowledge Area
216 - Integrated Pest Management Systems;

Subject Of Investigation
5220 - Pesticides;

Field Of Science
1130 - Entomology and acarology; 2000 - Chemistry;
Goals / Objectives
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. 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. 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. Specific Objective 3- Surface analysis and mechanism of interactions of AgNPs embedded stabilized with carbohydrates within nanoparticuclate constructs with cellular components. 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: 1. A method to synthesize different sizes of nanoparticles encapsulated in biological matrices with detailed toxicity characteristics. 2. Detailed toxicity profile of silver nanoparticles with respect to non-targeted pests. 3.The development of a set of nanoparticles with which to treat harmful pests or pesticide resistant microbes present in plants. 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.
Project Methods
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.

Progress 09/01/11 to 08/31/15

Outputs
Target Audience:Regional, National, and International Scientific community in the fields of Nanotechnology, Environmental Sciences, and Agriculture Pesticidal industry Farmers growing different agricultural products Students (graduate and undergraduate) Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One student graduated with a Master of Science form the Department of Agriculture and Environmental Science and completed her thesis working on this project. Another graduate student from Lincoln University joined the project this year and is anticipated to graduate by the end of the next year. One student started her Ph.D. program jointly with the University of Missouri-Columbia from the beginning of this project (Collaborating Institution) and will be graduating in a year. Year 2015: 3 undergraduate students worked on the project. All of the participant students have been receiving professional training through PI and Co-PIs mentorship. The students gained expertise in experimentation as well as use of the instrumentations and analysis of the reports. Every step of this study has been a scientific challenge for the involved scientists and it has resulted in a professional growth for the entire research group. Experimental results were discussed with other scientists in the field at National and International conferences. Our results emphasize the importance of studying the toxicity of nanoparticles before introducing them in large scale to the environment. Our presentations inspired other scientists that more work needs to be done in this area. How have the results been disseminated to communities of interest?Posters and research talks at regional, national, and international conferences in Environment Science and Agriculture. The audiences of the conferences were researchers in the field from various countries. What do you plan to do during the next reporting period to accomplish the goals?This year is the final year of the project. Our experimental rsults will be analyzed further. We will propose new projects based on our results.

Impacts
What was accomplished under these goals? This work assesses the influence of silver nanoparticles on life history parameters of two agricultural pests and a beneficial predatory insect species that act in agroecosystems. Two representative pests, Heliothis virescens (tobacco hornworm) and Trichoplusia ni (cabbage looper), and a beneficial predator, Podisus maculiventris (spined soldier bug) were chosen for this study.AgNPs of different size and shape synthesized with polysaccharide, glycoprotein, gelatin and polymer coating have been utilized for the present study. Gelatin, starch and gum arabic were chosen as surface coating materials due to their biodegradable nature. Physico-Chemical propertiesof the nanoparticles were studies by TEM, UV spectrophotometer, Nanozetasizer and other instrumentations. The influence of dietary AgNPs on both pest and predator species have been compared. AgNP-1 nanoparticles slightly increased time to pupation and adult emergence, but the other three did not have significant influence. Diets amended with lower AgNP concentrations did not influence days to pupation, pupae weights or time to adult emergence. We recorded similar results from cabbage loopers. Spined soldier bugs maintained on diets amended with AgNPs were delayed in their normal developmental excursion. Third instar nymphs on diets with AgNP-1 required an additional 5 days to molt into fourth instars. Dietary AgNP-1 and AgNP-2 similarly delayed in molting into fifth instars and the developmental delays in fifth instars were doubled to approximately 10 days. Lower dietary doses did not influence juvenile development times. The 100 ppm treatments also led to substantial reductions in the weights of newly-emerged adult males and females. Dietary AgNP-3 and AgNP-4 also led to reductions in adult weights. Female spined soldier bugs typically begin laying eggs at the age of 15 days. The AgNP treatments impacted the age of first oviposition. Females exposed to AgNP-1 began laying eggs sooner than controls, at age 12 days. However, the other three AgNPs delayed the onset of egg laying, by two days for AgNP-2 and AgNP-3 and by seven days for AgNP-4 respectively. The treatments also impacted the total number of eggs deposited over the 25-day course of the experiment, slightly increasing by 10 eggs/female (AgNP-1), and decreasing by 19 eggs/female (AgNP-2) and by 39 eggs/female (AgNP-3). AgNP-4 treatments did not influence egg laying. The AgNP treatments did not influence the rate of egg hatching, which ranged from 69-72% of the laid eggs for control and experimental soldier bugs. Dietary AgNP treatments also increased soldier bug mortality, from about 23% in controls to about 50% (AgNP-1) and 43% (AgNP-2). We infer from the delayed development, reduced adult weights, increased age of egg laying onset, reductions in numbers of eggs laid and nearly doubled mortality, that the AgNP treatments strongly reduced the ecological fitness of the spined soldier bug, an important beneficial insect in vegetable agroecosystems. The significance of our results is that reduced fitness of beneficial insects can exert profound effects on global agricultural production because most agroecosystems support a large number of pest and beneficial species.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: International Conference on Environmental Sciences, Vienna, Austria 2015
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Nanoscale Science & Engineering for Agriculture & Food Systems, Gordon Research Conference 2015, Waltham, MA
  • Type: Journal Articles Status: Under Review Year Published: 2015 Citation: Journal of Nanomaterials


Progress 09/01/13 to 08/31/14

Outputs
Target Audience: National and international 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? Two graduate and 2 undergraduate students have been receiving professional training through PI and Co-PIs mentorship. The students are gaining expertise in experimentation as well as use of the instrumentations and analysis of the reports. Every step of this study have been a scientific challenge for the involved scientists involved and it has resulted in a professional growth for the entire research group. How have the results been disseminated to communities of interest? The results have been presented as a speech in two separate International conferences in Environment Science and Agriculture. The audiences of these two conferences were researchers in the field from various contries. What do you plan to do during the next reporting period to accomplish the goals? We are planning to synthesize silver nanoparticles conjugated to eicosanoid inhibitors and apply it to pest and predetors diets and study their effect on fitness of pest and predators.

Impacts
What was accomplished under these goals? Silver nanoparticles used to feed the insects were well characterized by their physico-chemical properties We amended culture media for two crop pests (larvae of the lepidopteran pests; namely, the tobacco budworm, Heliothis virescens and the cabbage looper, Trichoplusia ni) and for one representative beneficial insect species (namely, the predatory soldier bug, Podisus maculiventris). We recorded life history parameters for all three species after the insects had ingested silver nanoparticle-laced diets. The studies were carried out with insect diets based on highest, moderate, and a low dilution of AgNPs. Our data suggests that AgNPs do not exert a biologically meaningful slowing of the developmental excursion in the studied pests. In sharp contrast, the outcomes of our experiments with the beneficial predator, P. maculiventris were quite different. Podius maculiventris is the most common of several species of podius, which has a wide host range, including several important crop pests.They were fed with a liquid diet encased in parafilm “bubbles” which the insects accessed through their piercing/sucking mouthpart. The studies on Podisus maculiventris were followed from second instar nymph to the adult stage. Nymphal development times from eggs hatched to third instar were approximately doubled for juveniles reared on media amended with two of the nanoparticles. Exposing the juveniles to media laced with AgNPs delayed the fourth to fifth instar development times by about five days, and from fifth instar to adult eclosion by about 10 days. Changes in the reproductive cycle of females and overall weight changes in adult insects were also investigated. Nanoparticle fed insects led to adults with significantly reduced body mass, reduced by about 10 mg/individual for males and females at all dilutions. AgNPs influenced fecundity of the beneficial insect. Adults from media treated with AgNPs delayed egg laying by about seven days compared to controls. These findings suggest that, AgNPs reduce the fitness of an important beneficial insect affecting agricultural produce. Viewed from the broad perspective of agro ecosystems, reductions in the fitness of beneficial insects could exert profound effects on global food production.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: ICSEA International Conference on Sustainable Environment and Agriculture, Silver nanoparticles as Pesticides November 2013, Abu Dhabi, UAE
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: ICSET International Conference on Sustainable Environmental Technologies, Nano-Pesticides August 2014, Dubai, UAE


Progress 09/01/12 to 08/31/13

Outputs
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

Impacts
What was accomplished under these goals? 1. Different sizes and shapes of silver nanoparticles encapsulated in gelatin, starch, and gum arabic were synthesized and characterized in detail with various instrumentations. The synthesis protocols were optimized 2. Stability studies of the synthesized nanoparticles were performed in different environments 3. Detailed studies were performed on toxicity of the synthesized nanoparticles on different generations of two pests and one predator species, a comprehensive set of data is generated and manuscripts for publications are being prepared.

Publications


    Progress 09/01/11 to 08/31/12

    Outputs
    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.

    Impacts
    Effect of AgNPs on pest H. virescens (Tobacco budworm): Pest caterpillars were fed NP-1 and NP-2 in artificial diet and monitored for death and developmental abnormalities throughout the larval, pupal, and moth stages. Pupas were weighed one day after pupation. Comparison of NP-1 and NP-2: H. virescens fed with NP-1 demonstrated small increases in mortality as the concentration of nanoparticle solution increased. The greatest amount of mortality observed was 11% at 181 ppm NP-1 compared to 6% for the controls. The length of development was slightly delayed at this concentration of NP-1 as well. Larvae fed NP-2 did not show any increased mortality or developmental delays. No significant differences were noted between the pupal weights or in developmental abnormalities for either NP-1 or NP-2. Effect of AgNPs on predator P. maculiventris (spined soldier bug): Predator insects were monitored for death and speed of development throughout the nymphal and adult stages. The weight changes of male and female predators were also compared. Comparison of NP-1 and NP-2: For both NP-1 and NP-2 fed insects, no difference in development was noted in nymphs and adults fed low concentrations in comparison with control insects. However, high concentrations of both NP-1 and NP-2 fed to P. maculiventris nymphs and adults significantly slowed developmental times and lowered adult weights in both males and females. Mortality for NP-1 (50%) and NP-2 (43.3%) fed insects was considerably higher than for control fed insects (23.3%). NP-1 nanoparticle fed adults weighed significantly less than control fed adults as did NP-2 fed females. Preliminary evaluation on pest and beneficial insects validate the development potential of AgNps for pesticide or bio pesticide carrier activity. Both pests and predators have late development impacts in different stages with AgNPs. The effect on predators is similar to the chemical pesticides currently being used for agriculture purposes (~25%). Further studies are currently being pursued to study other species of insects, and to vary of the size, shape of the AgNPs to proceed with a targeted approach towards pest insects.

    Publications

    • Z. Afrasiabi, F. Eivazi, H. Popham, D. Stanley, A. Upendran, R. Kannan, Silver Nanoparticles as Pesticides, NIFA USDA Project Directors' Conference September 16-19, 2012 hosted by Alabama A&M University