Photothermal-modulated drug release from a composite hydrogel based on silk fibroin and sodium alginate

Abstract

In order to realize effective controlled release of medicine to specific sites, the near-infrared (NIR) light responsive hydrogel has recently attracted noticeable attention as an innovative vehicle for a reserving and releasing the drug remotely “on demand” via stimuli-responsive NIR irradiation on/off. Herein, a modulated drug delivery platform was developed based on a silk fibroin (SF)/sodium alginate (SA) composite hydrogel incorporated with indocyanine green (ICG) as components. The gelation time of the crosslinked composite hydrogel ranged from 15 to 35 min, mainly depending on the concentration of SF. These materials are typical elastic hydrogels display stiffness between 260 and 2210 Pa. Besides, the compressive modulus E of the hydrogels varied in the range of 0.89–1.71 kPa by changing blend ratios. Scanning electron microscope (SEM) revealed the hydrogels showed highly porous (~89%) and tailored pore size in the range of 132–215 µm. And SF mainly remained silk I structure in the composite hydrogel and bovine serum albumin (BSA) and tetracycline hydrochloride (TH) still kept their own structure after encapsulation. SF/SA@ICG hydrogels exhibited desirable stability and swelling properties. Additionally, these hydrogel extracts displayed good cellular compatibility in vitro. Under near-infrared (NIR) radiation exposure, the hydrogels exhibited photothermal properties such as temperature rise by 8 °C, sufficient to stimulate drug release. Furthermore, hydrogels demonstrated NIR stimulated drug release, which was evaluated using BSA and TH, the drug loaded photothermal hydrogels can effectively increase the amount of drug released under NIR light trigger for just 1 min. The NIR-responsive hydrogels can provide a new option for developing natural ploymer based delivery vehicles to regulate drug release on demond using NIR irradiation remotely.