A protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating

Authors: Kim, Sanghoon

Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2015
Publication Date: 7/8/2016
Citation: Kim, S. 2016. A protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating. Journal of Visualized Experiments. doi:10.3791/54147.

Interpretive Summary: In previous research, we have presented a method for the production of nanoparticles composed of a cereal protein (gliadin) and a biodegradable synthetic polymer [poly(ethyl cyanoacrylate)]. Nanoparticles are small particles not visible to the naked eye. The produced nanoparticles have such strong adsorption characteristics that they can be used as a coating material applied to the surface of non-wetting objects. If transparent window materials such as glass or Plexiglas are coated with these nanoparticles, the visibility will improve on rainy days without deteriorating its transparency. This manuscript is written for a video journal that illustrates the actual experimental procedures and demonstrates the performance of the final product. The nanoparticle product can be commercialized in the form of spray for hydrophilic coating. Since both gliadin and poly(ethyl cyanoacrylate) are degradable polymers, the developed nanoparticles are environmentally safe and degradable. This video presentation will demonstrate a detailed manufacturing process for the production of a surface-coating solution and select application processes. Scientists in industry and academia developing surface-modifying products would benefit.

Technical Abstract: This article presents a protocol for the production of protein-based nanoparticles that change the hydrophobic surface to hydrophilic by a simple spray coating. These nanoparticles are produced by the polymerization reaction of alkyl cyanoacrylate on the surface of cereal protein (gliadin) molecules. Alkyl cyanoacrylate is a monomer that instantly polymerizes at room temperature when it is applied to the surface of materials. Its polymerization reaction is initiated by the trace amounts of weakly basic or nucleophilic species on the surface, including moisture. Once polymerized, the polymerized alkyl cyanoacrylates show a strong affinity with the object materials because nitrile groups are the backbone of poly (alkyl cyanoacrylate). Proteins also work as an initiator for this polymerization because they contain amine groups that can initiate the polymerization of cyanoacrylate. If aggregated protein is used as an initiator, protein aggregate is surrounded by the hydrophobic poly(alkyl cyanoacrylate) chains after the polymerization reaction of alkyl cyanoacrylate. By controlling the experimental conditions, particles in the nanometer range are produced. The produced nanoparticles readily adsorb to the surface of most materials including glass, metals, plastics, wood, leather, and fabrics. When the surface of a material is sprayed with the produced nanoparticle suspension and rinsed with water, the micellar structure of the nanoparticle changes its conformation, and the hydrophilic proteins are exposed to the air. As a result, the nanoparticle-coated surface changes to hydrophilic.