An Investigation Into Using Regenerated Cellulose-based Electro-conductive Composites for Actuation and Drug Delivery
Chowdhury, Nargis Afroj
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Under the influence of an electric field, ionic electro-active polymers generally bend or deswell, depending on the shape of the polymer matrices and its position relative to the electrodes. In this study, we investigate the bending behaviour of regenerated cellulose-based ionic electro-active composites for the fabrication of soft actuators with improved actuation force and durability. This research also focuses on the externally induced (electrically and magnetically) matrices deswelling and other responses, which affect the release of drug from the matrices. For actuation studies, we prepared matrices by combining carbon nanofibers, conducting polymers, and ionic liquids (through blending, doping, or coating) into the regenerated cellulose. We observed that actuators coated by polypyrrole doped with anthraquinone-2-sulfonic acid sodium salt monohydrate showed improved electrical conductivity and durability compared to that of using perchlorate ion as the dopant. This is due to the preparation process and the effect of dopants that play an important role to improve the performance of the regenerated cellulose-based ionic electro-active actuators. In addition, we investigated the influence of electrode design (layer-by-layer structure) on the properties of the actuators. Further, in this study, we developed three types of matrices consisting of regenerated cellulose/functionalized carbon nanofibers, regenerated cellulose/functionalized carbon nanofibers/polypyrrole, and regenerated cellulose/γ-ferric oxide/polypyrrole. We investigated the effects of electric field strength and electrode polarity on the release rate of sulfosalicylic acid (drug) in an acetate buffer solution with pH 5.5 and temperature 37 ᵒC during a period of 5 h. Drug release rate from the matrices containing carbon nanofibers (additives) increased effectively with increasing applied electric field. The mechanism of drug release from drug-doped polypyrrole coated matrices includes expansion of conductive polymer chain and the electrostatic force between electron and drug. The novelty of the work is- the matrices can also work under magnetic field and consequently, one can be beneficial from a contactless actuation. In this study, we also investigated electrical conductivity, morphology, swelling behaviour of the composite matrices, electro-active composite-drug interaction, and in vitro drug release behaviour of the matrices. Further, a comparative study was performed on the rate of drug release from the matrices induced by electric and magnetic field.