423 Mikhail Soloviev (ed.), Nanoparticles in Biology and Medicine: Methods and Protocols, Methods in Molecular Biology, vol. 906, DOI 10.1007/978-1-61779-953-2_35, © Springer Science+Business Media, LLC 2012 Chapter 35 Assessment of Toxicity of Nanoparticles Using Insects as Biological Models Yan Zhou, Aracely Rocha, Carlos J. Sanchez, and Hong Liang Abstract Nanomaterials have become increasingly important in medicine, manufacturing, and consumer products. The fundamental understanding in effects of nanoparticles (NPs) on and their interactions with biomolecules and organismal systems have yet to be achieved. In this chapter, we firstly provide a brief review of the interactions between nanoparticles and biological systems. We will then provide an example by describing a novel method to assess the effects of NPs on biological systems, using insects as a model. Nanoparticles were injected into the central nervous system of the discoid cockroach ( Blaberus discoidalis). It was found that insects became hyperactive compared to negative control (water injections). Our method could provide a generic method of assessing nanoparticles toxicity. Key words: Nanomaterials, Toxicity , Insects, Nervous system, Magnetic nanoparticles, Cockroach walking distance Nanomaterials are known to have a wide spectrum of applications in biomedical, chemical, electronical, material, optical, and physi- cal sciences. The properties of nanoparticles (NPs) are unique from their bulk due to the quantum effects (1–3). In bio-applications, NPs have been used to detect genetic disorders, cell labeling, gene therapy, and drug delivery (4–6). Here are a few examples of those commonly used in biomedical research and applications. The core-shell nanoparticles are generally spherical cores encapsulated by a shell of another material. The shell is generally a few nanometers in thickness and has been found to absorb a certain wavelengths in order to increase energy. For example, a core of silica coated by gold shell is used to kill surrounding cells by generating heat after radiation (7). 1. Introduction