Alternative synthesis methods of electrically conductive bacterial cellulose-polyaniline composites for potential drug delivery application

摘要

Bacterial cellulose/polyaniline (BC/PANi) nanocomposites have been lately receiving attention by the scientific community towards the development of electronic applications. The current work aims to determine the most suitable BC modification method to obtain an effective drug delivery membrane through electric stimulus. Thus, the BC/PANi nanocomposites were synthesized through the employment of different BC matrixes (drained, freeze dried and regenerated), as well as through different polymerization methods (in situ and ex situ). Prior to modification, the effects of both drying methods (freeze drying and oven drying), and regeneration process on BC structure were studied. By freeze drying BC, the fibril network is preserved, leading to a more porous material. On the other hand, regenerated BC presented a compact surface due to the incapacity to reorganize into fibrils during the regeneration process. This way, freeze dried BC should be more suited for modification. To obtain a highly conductive nanocomposite, the in situ polymerization on drained BC should be employed. The introduction of PANi onto BC obstructed the pores, which led into a more compact and rougher material. Also, a decrease in the thermal stability, as well as a decrease in the BC crystallinity was observed. The nanocomposites were drug loaded with sodium sulfacetamide to evaluate the antimicrobial activity. It was observed that without electrical stimulus, only drug loaded drained in situ BC/PANi nanocomposite presented an inhibitory effect onto the Escherichia coli (E. coli) growth (13%). By applying electric stimulus onto this membrane, the inhibition in E. coli growth is further evidenced (20%). This way, in situ polymerization of aniline on drained BC presented to be an effective method to create a highly conductive membrane for drug release through electrical stimulus.