Copolymer-grafted halloysite nanotubes embedded in electrospun fibers as a composite carrier for doxorubicin delivery

Halloysite nanotubes (HNTs) are fascinating carriers for the delivery of chemotherapy drugs. Surface modification of HNTs and their loading in polymer matrixes can create a delivery system with more controlled and sustained drug release. Taking this into account, in the present research, a drug delivery system was made by grafting a block copolymer of polyacrylic acid (PAA)/polyaniline (PANI) on HNT surface and incorporating copolymer-grafted HNTs into the polycaprolactone (PCL) fibers. For this purpose, PANI-b-PAA copolymer was first formed on HNT surface by grafting from strategy. Then, the copolymer-grafted HNTs and doxorubicin were loaded into PCL solution and the composite solution was processed by electrospinning. Preliminary evaluations confirmed the successful grafting of PANI-b-PAA copolymer onto HNTs. SEM and EDS analyses showed that drug loaded composite nanofibers have an average diameter of 396 nm and a uniform distribution of HNTs and doxorubicin. Drug release study revealed that composite nanofibers have less burst release and more sustained release than PCL nanofibers. Investigation of drug release mechanism by kinetics models corroborated that the drug release from composite nanofibers is mainly controlled by Fickian diffusion. Cell culture experiment verified that the composite nanofibers have higher cytotoxic effects and kill more tumor cells compared to PCL nanofibers. In summary, modifying the surface of HNT and incorporating it into PCL nanofibers can create a drug carrier with more sustained drug release and higher antitumor effects.