Silk fibroin coaxial bead-on-string fiber materials and their drug release behaviors in different pH

Inspired by the different pH between normal tissue and tumor tissue, pH-responsive drug release materials need to be designed to achieve drug-controlled release. Electrospinning is a simple and efficient method to fabricate drug loading and releasing materials. However, burst release of electrospun smooth fibers was often observed in drug delivery process, which is very harmful to the human body. To develop materials with drug sustained release behaviors in tumor tissue environment, different morphologies of electrospun materials should be designed and fabricated. In this study, silk fibroin smooth fiber materials, bead-on-string fiber materials and coaxial bead-on-string fiber materials were fabricated and their drug release behaviors were compared in different pH. The drug release experiments showed that the electrospun materials showed pH-sensitive releasing behaviors. They released faster and more amount of drugs in acid buffer. Besides, the electrospun coaxial bead-on-string fiber material has a slower release rate compared with the smooth fiber and bead-on-string fiber materials. The coaxial bead-on-string fiber material is an efficient and of potential for being used as sustained drug delivery system to treat cancers.