Assembly-Controlled Permeability of Layer-by-Layer Polymeric Microcapsules Using a Tapered Fluidized Bed

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• 作者：Ka Fung Noi ; Ali Roozmand ; Mattias Bj?rnmalm ; Joseph J. Richardson ; George V. Franks ; Frank Caruso
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 23, 2015
• 年：2015
• 卷：7
• 期：50
• 页码：27940-27947
• 全文大小：521K
• ISSN：1944-8252

文摘

Nano- and microcapsules engineered through layer-by-layer (LbL) assembly are finding an increasingly large number of applications as catalysts, electrochemical biosensors, bioreactors, artificial cells and drug delivery vehicles. While centrifugation-based LbL assembly is the most common method for coating template particles and preparing capsules, it is a batch process and requires frequent intervention that renders the system challenging to automate and scale up. Here, we report the use of a tapered fluidized bed (TFB) for the preparation of multilayered polymer capsules. This is a significant improvement over our recent approach of fluidizing particles in cylindrical fluidized beds (CFB) for LbL assembly. We demonstrate that TFB is compatible with particles <3 μm in diameter (an order-of-magnitude improvement compared with CFB), which can be fluidized with minimal entrainment. Additionally, layering materials were expanded to include both electrostatic and hydrogen-bonding polymer pairs (e.g., poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate) (PSS), and thiol-modified poly(methacrylic acid) (PMA_SH) and poly(N-vinylpyrrolidone) (PVPON), respectively). Finally, differences between capsules prepared via centrifugation-based and TFB LbL assembly were investigated. The obtained TFB microcapsules demonstrate increased film thickness and roughness compared with those prepared using centrifugation-based LbL assembly. Furthermore, PMA_SH microcapsules exhibit lower swelling and permeability when prepared via TFB LbL assembly compared with centrifugation-based LbL assembly due to enhanced multilayer deposition, entanglement, and cross-linking. Therefore, polymeric capsules fabricated via TFB LbL assembly may be useful for encapsulation and retention of relatively low molecular weight (～20 kDa) hydrophilic biomacromolecules to passively or responsively release the payload for drug delivery applications.