Thermal-responsive biodegradable composite membrane for drug delivery application

Drug delivery systems have been engineered in order to improve therapeutic performance and reduce the side effects of conventional delivery system like oral ingestion, subcutaneous injection [1-2]. There exist several types of drug delivery systems, among which the most advanced consist of drug delivery implants [3-5]. As part of the general challenge for implantable smart, hence controllable, drug releasing systems, we present here a study on thermal-responsive biodegradable composite membrane composed of silk fibroin and iron oxide nanoparticles. Our scientific question currently is to understand if iron oxide embedded in a silk membrane can be used to locally heat the silk as an active and localized drug delivery implant. Here we focus on two aspects: first, ethanol annealing method is used to induce beta-sheet structures inside silk fibroin films in order to get stable films, which can be kept in water for several days. Importantly, we demonstrate for instance, that the thermal stability of silk fibroin films after ethanol annealing does not change, and their thermal degradation occurs above 200 °C. Second, we have found that the magnetic heating rate is proportional not only to the amount of magnetic nanoparticles but also the magnetic filed flux and frequency. The maximum heating rate achieved under experimental condition is around 20 °C/min as measured by optical temperature sensor. To demonstrate the potential use as drug release control mechanism, we show that holes in silk fibroin film with magnetic nanoparticles occur after magnetic heating.