doi:10.1038/nindia.2015.63 Published online 15 May 2015
Researchers have synthesized an injectable silk hydrogel that can deliver tissue-regenerating drugs to degenerated discs through minimally invasive surgery, making it potentially useful for treating degenerative disc disease1.
Disc degeneration afflicts millions of elderly people. It is often treated by surgically implanting artificial implants in degenerated discs, but this treatment generally fails to restore full mobility to patients and can cause post-operative trauma.
The researchers synthesized hollow silk microspheres and loaded them with a drug widely used to treat osteoarthritis. They then produced an injectable silk hydrogel system by embedding the drug-loaded microspheres in silk hydrogel.
The researchers investigated the efficacies of the microsphere-based silk hydrogel system to produce glycosaminoglycan and collagen that help regenerate nucleus pulposus cells, which mainly form the inner part of intervertebral discs. When they cultured human adipose-derived stem cells in the silk hydrogel, the silk microspheres slowly released the drug, which enhanced glycosaminoglycan production. This, in turn, activated certain signaling molecules that participate in tissue regeneration.
Injecting 2% silk-in-silk hydrogel restored compressive properties to bovine degenerated discs, indicating the potential of this system as a drug- and cell-delivery platform. “This injectable drug-loaded silk hydrogel system can be directly delivered to degenerated sites through minimally invasive surgery by using a syringe,” says lead researcher Sourabh Ghosh.