Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

Abstract

Abstract. By combining LbL (layer-by-layer) self-assembly approach and host-guest interactions, a unique multilayer film was constructed and employed for a light-controlled drug release system. The drug molecules can be loaded and released into the resulting polyelectrolyte multilayers containing azobenzene (Azo) function groups by using the irradiation of visible light and UV light alternately. The photo-sensitivity of the multilayer films was studied through UV-vis spectrum, fluorescence spectrum and confocal microscopy. The target molecules could be rapidly released from the multilayers after 300 W UV light irradiation for 20 minutes. Moreover, they could be readsorbed into the multilayers uniformly when illuminated under the 300 W visible light for 10 minutes confirmed by the observation of confocal microscopy, and the readsorption ratio exceeds 100% evidenced from UV-vis spectroscopy. After several cycles of the above-mentioned process, the multilayer films show good fatigue resistance. All these results indicate the photo-sensitivity and high-efficiency of the multilayer films, which have great potential in controlled drug delivery platform and biomedical applications. : coatings, layer-by-layer, host-guest interactions, light response, drug delivery eXPRESS Polymer Letters Vol.8, No.3 (2014) 143-153 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2014.18 * Corresponding author, e-mail: softmatter@163.com © BME-PT nating irradiation with UV and Vis light allows for reversible sliding of !-CD along the surfactant, leading to the formation of rotaxane-like vesicles. Based on this principle, light-responsive host-guest assembly and disassembly between Azo and CD hold great potential to design a reversible drug delivery profile [16,17]. Layer-by-layer (LbL) self-assembly approach is particularly well-suited for fabricating functional multilayer thin films with ultrafine nanometer-scale structure for use as drug delivery vehicles [18][19][20][21]. The traditional means of loading drugs on layers of LbL platform always uses physical adsorption or chemical bonding. However, these methods of loading drugs have a common drawback: drug loading and release is irreversible. This is a critical problem in LbL multilayers for drug delivery. Therefore, it's desired to devise a reversible LbL-based system to manipulate the drug release in a more controllable manner. In the past decade, the pioneering work on LbL assembly with supramolecular interaction has been established by Ikeda et al. [22]. Subsequently, Smith et al. [23] have reported that loading smallmolecule drugs on the layers of LbL-based system using supramolecular interaction. On another front, the light-induced drug release from a LbL-based system is the most elegant way to combine reversibly and efficiency, because light as an attractive stimulus can be applied rapidly, remotely, and locally [24,25]. While numerous well-established photoresponsive LbL-based systems are available [26,27], their applications in drug release b...

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