Block copolymer micelles (BCMs) are ideal drug carriers due to their hydrophobic core regions which can encapsulate water insoluble drug molecules. BCMs with stimuli-responsive cores are of specific interest due to release of the cargo by simply changing the environmental conditions, e.g. pH, temperature, ionic strength. Incorporation of BCMs into layer-by-layer (LbL) films is important to keep the BCMs stable in bloodstream and prevent the release of the cargo at an early stage. In addition, BCMs increase the loading capacity of the LbL films for functional hydrophobic molecules. In this study poly[2-(dimethylamino)ethyl methacrylate-b-poly(2-(diethylamino)ethyl methacrylate)] (PDMA-b-PDEA) micelles with pH/temperature responsive PDMA-coronae and pH-responsive PDEA-core structure were used as building blocks to construct LbL films using poly(sodium 4-styrenesulfonate) (PSS) as the polymer counterpart. The effect of film deposition pH and temperature on the properties of the multilayers were investigated in detail. It was found that only 0.5-unit difference in the pH of polymer solutions resulted in a significant difference in the stability of the multilayers in the pH-scale. It was also demonstrated that the effect of film deposition temperature on the properties of the resulting films were highly pH-dependent. In addition, pH-induced release of a hydrophobic dye, pyrene, from BCMs within the multilayer surface was investigated at 25°C and 37°C. It was found that increasing temperature resulted in an increase in the amount of pyrene released from the surface at moderately acidic pH. In this respect, our system is promising for release of biologically functional molecules at acidic conditions due to acidic nature of tumor tissues or pH drop in the body at an infected site.

Effect of film deposition conditions on the properties of multilayer films of a dual responsive block copolymer micelle

254th National Meeting (2017)

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