Aqueous-based electrospun P(NIPAAm-<i>co</i>-AAc)/RSF medicated fibrous mats for dual temperature- and pH-responsive drug controlled release

Abstract

This paper presents a green method for fabricating dual temperature- and pH-responsive electrospun fibrous mats from an aqueous-based blend poly(<i>N</i>-isopropylacrylamide-<i>co</i>-acrylic acid) (P(NIPAAm-<i>co</i>-AAc)) and regenerated silk fibroin (RSF) by employing electrospinning technique. P(NIPAAm-<i>co</i>-AAc) was synthesized by free radical solution polymerization and its low critical solution temperature (LCST) was in the physiological range (38.8 °C). The P(NIPAAm-<i>co</i>-AAc)/RSF fibers were prepared by electrospinning technology in the presence of the crosslinking agents (EDC·HCl and NHS) with water as solvent. After <i>in situ</i> crosslinking and water-annealing process, the water-stable composite fibrous mats were obtained. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the crosslinking process. Temperature and pH dual stimuli-responsive swelling-shrinking behavior of the fibrous mats were observed when the temperature was below and above the LCST of the copolymer at different pHs. In addition, rhodamine B-loaded the fibrous mats also showed dual temperature and pH controlled release behavior, demonstrating the potential use of the fibrous mats for "smart" controlled drug delivery applications.