a SciTechnol journal Research Article Pokhrel et al., Expert Opin Environ Biol 2013, 2:1 http://dx.doi.org/10.4172/2325-9655.1000103 Expert Opinion on Environmental Biology All articles published in Expert Opinion on Environmental Biology are the property of SciTechnol, and is protected by copyright laws. Copyright © 2013, SciTechnol, All Rights Reserved. International Publisher of Science, Technology and Medicine Evaluation of Experimental Design Options in Environmental Nano-Science Research Lok R. Pokhrel 1 , Phillip R. Scheuerman 1 and Brajesh Dubey 2 * Abstract As an experimental research design plays a pivotal role in executing a research problem, it is imperative of a researcher to develop a suitable and sound research design. Utilizing robust statistical methods can further enhance the study power and thus allow drawing a logical conclusion. The same holds true for basic environmental science research, including research related to the effects of engineered nanomaterials in the environment. In this paper, we (i) provide a succinct overview of multiple experimental design options that are available to conduct environmental research with focus on emerging nanomaterial science research; (ii) outline the pros and cons of various study designs providing examples as appropriate; (iii) identify and discuss the challenges facing nano- researchers in quantifying and characterizing nanomaterials; and (iv) provide a perspective on how these challenges can be addressed in a situation when instrumentations and protocols that have been used for conventional toxicant characterization are purportedly less suitable for gaining insights into interactions potentially occurring at bio-nano interfaces to explain nanotoxicology. Keywords Experimental design; Nanotoxicology; Nanomaterials; Randomiza- tion; Higher level design *Corresponding author: Brajesh Dubey, Environmental Engineering, School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario, Canada, Tel: +1-519-824-4120; E-mail: bdubey@uoguelph.ca Received: January 27, 2013 Accepted: March 18, 2013 Published: March 22, 2013 to build upon the hypothesis that is generally accepted. his is the basis of any scientiic inquiry which attempts to provide a logical understanding of the properties and processes associated with the subject at hand. As a researcher develops interest in a research project, thorough literature search is pursued, followed by discussion and brain- storming within the research group to address any shortcomings. his will allow the researchers to reine the project to better accomplish the research goals. he researcher develops hypotheses based on the problem statement, which are then executed following speciic experimental design(s) per the need and nature of the research. he success of any scientiic research is largely dependent on its experimental design. Many kinds of experimental designs have been practiced to generate empirical data in various research settings. At the heart of rapidly growing nanotechnology lies the purposely manipulated matter in the atomic scale, called the engineered nanomaterials. Engineered nanomaterials have been the subject of increasing interest for material scientists in recent years as they demonstrate uniquely unusual properties [1-3], which are being harnessed for developing high-value products at low cost [1,3]. heir continual applications in various commercial products have raised signiicant concern for environmental release [4,5] and subsequent environmental hazard which is beginning to emerge [1,2,6-9]. Potential risk of nanomaterials, however, remains to be assessed due to (i) the lack of standards, protocols, and instrumentations to directly quantify nanomaterials, (ii) batch-wise heterogeneity among nanomaterial samples, (iii) instrument-wise variability in particle sizing [9], and (iv) less understanding of interactions potentially occurring at nano-bio interfaces [8]. In this paper, we provide insights into various experimental designs that are used in environmental nano-science research, address the strengths and weaknesses of these research designs, identify and discuss the challenges facing the nano-researchers in quantifying and characterizing nanomaterials, and ofer a perspective on how these challenges can be addressed when existing standard protocols and instrumentations that have been routinely used for characterizing conventional toxicants may be less suitable for gaining insights into interactions potentially occurring at nano-bio interfaces when explaining environmental toxicology of engineered nanomaterials. Experimental Designs One-shot design his is a design in which a group of test subjects is exposed to a chemical, a drug, or any other treatment, and then the response is measured. his design does not randomize the subjects, nor does it incorporate a control group for comparison [10]. For example, considering the necessity of understanding potential toxicity of silver nanoparticles – one of the widely used nanomaterials in commercial applications today [11] – in plants, a few seeds of a particular plant species can be treated with a single concentration of silver nanoparticles and observe for certain end points (e.g., germination rate, root/shoot growth, DNA damage) [9]. One-shot design can be particularly useful for screening the potential toxicity of any novel Introduction he objective of a scientiic research is to understand the phenomenon underlying the research problem by using a systematic approach which enables researchers to predict, explain, or determine the causal relationship between the variables by precisely manipulating or controlling the experimental conditions. A research study is valued based upon its completeness and integrity. To meet this goal, it becomes crucially important that the research is carried out using sound experimental design(s), and appropriate statistics be applied to test the hypothesis and draw a logical conclusion. Any empirical data collected using a robust research methodology facilitates higher reproducibility of the results, which provides a logical platform