一种醇溶蛋白氰基丙烯酸酯纳米粒子为亲水涂料生产协议
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
本文介绍用于生产基于蛋白的纳米颗粒，通过一个简单的喷涂改变疏水性表面的亲水性的协议。这些纳米颗粒通过烷基氰基丙烯酸酯的谷蛋白（麦醇溶蛋白）的分子的表面上的聚合反应来制备。烷基氰基丙烯酸酯为单体时，它被施加到材料的表面，可以立即在RT聚合。其聚合反应是通过在表面上的弱碱性或亲核物种，包括湿气的痕量启动。一旦聚合，聚合氰基丙烯酸烷基酯显示出很强的亲和力与对象材料，因为腈基是在聚（烷基氰基丙烯酸酯）的支柱。蛋白也作为引发剂用于这种聚合反应，因为它们含有能引发氰基丙烯酸酯的聚合胺基。如果聚集的蛋白用作一种引发剂，蛋白聚集是由疏水包围聚（烷基氰基丙烯酸酯）的烷基腈基丙烯酸酯的聚合反应后链。通过控制实验条件下，在纳米范围内的颗粒产生。所产生的纳米颗粒容易吸附到大多数材料，包括玻璃，金属，塑料，木材，皮革和织物的表面上。当材料的表面喷涂所生成的纳米颗粒悬浮液，并用水漂洗，纳米颗粒的胶束结构改变其构象，和亲水性蛋白质暴露在空气中。其结果是，纳米颗粒涂覆的表面改变为亲水性的。
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…
Disclosures
The authors have nothing to disclose.
Acknowledgements
感谢Jason阿德金斯先生专家的技术援助。
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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