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This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic. The produced nanoparticle is an assembly of gliadin-cyanoacrylate diblock copolymers. Spray coating with the produced nanoparticle changes the surface of target material to a hydrophilic surface.
This article presents a protocol for the production of protein-based nanoparticles that changes 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 RT 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 in the backbone of poly (alkyl cyanoacrylate). Proteins also work as 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 condition, 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 nanoparticle changes its conformation, and the hydrophilic proteins are exposed to the air. As a result, the nanoparticle-coated surface changes to hydrophilic.
The goal of this article is to show the protocol for the preparation of nanoparticle suspension that modifies the wetting property of materials by a simple spray. The presented nanoparticle suspension is made from alkyl cyanoacrylate1 and a cereal protein, gliadin2,3. During the manufacturing process, protein aggregates are formed in aqueous ethanol4. Subsequent reaction with monomer (alkyl cyanoacrylate) produces the nanoparticle that is comprised of a protein core surrounded by linear polymer chains [poly(alkyl cyanoacrylate)]5.
Poly(alkyl cyanoacrylate)s are biodegradable and have been used for....
1. Defatting Commercial Gliadin
Nanoparticles can be prepared in various reaction conditions. Gliadin forms aggregate in broad range of ethanol content5. However, the size of aggregates needs to be as small as possible because an additional layer (i.e., polymerized ECA) will be added to this aggregate and this process will make the final size larger. If the final size of particle is too large, the particle will be unstable and will easily be precipitated. Therefore, 68% aqueous ethanol was chosen as .......
There are several critical steps in the production of the nanoparticle suspension. If the purified gliadin contains impurities, the reaction with ECA will produce side products. Although these unwanted products can be removed from the reaction medium during the centrifugation stage, it lowers the yield of the major product. If the gliadin solution prepared during experimental step 2.3) does not show clear separation between supernatant and precipitate after two days, the solution needs to stand for longer time. Using fre.......
Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.
Thanks to Mr. Jason Adkins for expert technical assistance.
....Name | Company | Catalog Number | Comments |
Ethyl cyanoacrylate (ECA) monomer | K&R International (Laguna Niguel, CA) | I-1605 | Any pure ECA can be used. |
Gliadin | MGP Ingredients, Inc (Atchison, KS) | Gift from the company | Gliadin can be purchased from Sigma-Aldrich (cat #: G3375-25G). Instead of gliadin, any commercial gluten can be used. |
HCl | Any | Any reagent grade chemical can be used. | |
Acetone | Any | Any reagent grade chemical can be used. | |
Methanol | Any | Any reagent grade chemical can be used. | |
Ethanol (100%) | Any | Any reagent grade chemical can be used. | |
Filter paper | Any | Any grade filter paper larger than 10 cm can be used. | |
Cell culture square dish | Any | Any dish larger than 20 cm x 20 cm can be used. | |
Coffee grinder | Any | Any coffee grinder can be used. | |
Rotary evaporator | Any | Any rotary evaporator can be used. | |
Freeze Dryer | Any | Any freeze dryer that can reach - 70°C can be used. | |
Centrifuge | Any | Any centrifuge that can apply 1000 x g can be used. | |
Magnetic stirrer | Any | Any magnetic stirrer that can turn spin bar to 1000 RPM can be used. | |
Dynamic Light Scattering (DLS) | Brookhaven Instruments Corporation | NanoBrook Omni Zeta Potential Analyzer | DLS from any company can be used. |
Scanning Electron Microscope (SEM) | Carl Zeiss Inc. | Any SEM can be used. | |
Dynamic Contact Angle (DCA) | Thermo Cahn Instruments | Any DCA can be used. |
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