Um protocolo para a produção de nanopartículas Gliadina-cianoacrilato para hidrofílico Coating
Summary
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.
Abstract
Este artigo apresenta um protocolo para a produção de nanopartículas à base de proteína que modifica a superfície hidróf oba para hidrófila por um simples revestimento por pulverização. Estas nanopartículas são produzidos pela reacção de polimerização de cianoacrilato de alquilo na superfície de moléculas de proteína de cereais (gliadina). Alquilo é um monómero de cianoacrilato que instantaneamente polimeriza à TA quando ele é aplicado à superfície dos materiais. A sua reacção de polimerização é iniciada por os vestígios de espécies fracamente básicos ou nucleofílicos na superfície, incluindo humidade. Uma vez polimerizado, os cianoacrilatos de alquilo polimerizados mostram uma forte afinidade com os materiais objecto porque grupos nitrilo estão no esqueleto de poli (cianoacrilato de alquilo). As proteínas também funcionam como iniciador de polimerização para este porque contêm grupos amina que podem iniciar a polimerização de cianoacrilato. Se a proteína agregada é usado como um iniciador, de agregados de proteína é rodeado pelo hidrofóbicopoli (cianoacrilato de alquilo) correntes após a reacção de polimerização de cianoacrilato de alquilo. Ao controlar a condição experimental, as partículas na gama dos nanómetros são produzidos. As nanoparticulas produzidas prontamente adsorver à superfície da maioria dos materiais, incluindo vidro, metais, plásticos, madeira, couro e tecidos. Quando a superfície de um material é pulverizado com a suspensão de nanopartículas produzida e lavada com água, a estrutura micelar de nanopartículas muda a sua conformação, e as proteínas hidrófilas estão expostas ao ar. Como resultado, a superfície revestida de nanopartículas muda para hidrofílico.
Introduction
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 the production of nanoparticles via emulsion polymerization6. This reaction is spontaneously initiated by the hydroxyl groups dissociated from water or by other nucleophilic groups in the reaction medium7. In the case of the reaction presented in this article, the amine groups on the surface of protein aggregates initiate the polymerization reaction of alkyl cyanoacrylate monomers5,8. As a result of this reaction, nanoparticles are formed in the reaction medium. The core of the nanoparticle is protein aggregates and the outer layer is poly(alkyl cyanoacrylate) (PACA) chains. The prepared nanoparticle has a strong affinity on most materials (more precisely, any material which PACA can adsorb to) and adheres onto their surface to form a thin coating on a nanometer scale. A simple spray coating instantly turns the surface of the materials hydrophilic.
Gliadin is one of the main fractions of gluten, which is in the endosperms of wheat. Gliadins are mainly monomeric proteins with molecular weights around 28,000 – 55,000. Non-covalent bonds such as hydrogen bonds, ionic bonds and hydrophobic bonds are responsible for the aggregation of gliadins2. Although gliadin is chosen as a reactant in this article, many other proteins can also be used for the same purpose. However, the reaction condition needs to be modified accordingly because the condition for inducing aggregation is dependent on the type of protein to be employed8. Compared with other proteins, gliadin is more readily available, purification is simple, and production cost is low. Although ethyl cyanoacrylate (ECA) is chosen as a monomer for the presented reaction, other alkyl cyanoacrylates can also be used for the same reaction. The reason for choosing ECA is that it is readily available at low cost.
Protocol
Representative Results
Discussion
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…
Declarações
The authors have nothing to disclose.
Acknowledgements
Graças ao Sr. Jason Adkins para assistência técnica especializada.
Materials
| 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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