Un protocollo per la produzione di nanoparticelle gliadina-cianoacrilato per rivestimento idrofilo
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
Questo articolo presenta un protocollo per la produzione di nanoparticelle a base di proteine che cambia la superficie idrofobica ad idrofilica da un semplice rivestimento a spruzzo. Queste nanoparticelle sono prodotte dalla reazione di polimerizzazione di alchil cianoacrilato sulla superficie della proteina cereali (gliadina) molecole. Alchil cianoacrilato è un monomero che polimerizza immediatamente a RT quando viene applicato alla superficie dei materiali. La reazione di polimerizzazione viene iniziata dalle tracce di specie debolmente base o nucleofili sulla superficie, comprese umidità. Una volta polimerizzato, i cianoacrilati alchil polimerizzati mostrano una forte affinità con i materiali degli oggetti, perché i gruppi di nitrile sono la spina dorsale di poli (cianoacrilato alchil). Proteine funzionano anche come iniziatore di polimerizzazione per questo perché contengono gruppi amminici che possono avviare la polimerizzazione di cianoacrilato. Se proteine aggregate viene usato come iniziatore, aggregata proteina è circondato dal idrofobicapoli (alchil cianoacrilato) catene dopo la reazione di polimerizzazione di alchil cianoacrilato. Controllando la condizione sperimentale, particelle nell'intervallo nanometri sono prodotti. Le nanoparticelle prodotte facilmente adsorbono alla superficie della maggior parte dei materiali tra cui vetro, metalli, plastica, legno, pelle e tessuti. Quando la superficie di un materiale è spruzzato con la sospensione nanoparticelle prodotte e risciacquata con acqua, la struttura micellare di nanoparticelle cambia la sua conformazione, e le proteine idrofile sono esposti all'aria. Come risultato, la superficie delle nanoparticelle rivestite cambia in idrofila.
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…
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
Grazie al Sig Jason Adkins per l'assistenza tecnica di esperti.
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. |
Referenzen
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