Biodegradable scaffolds are an important part of tissue engineering, providing a way to hold cells in place and shape their growth in three dimensions, breaking down gradually as the new tissue builds its own supporting extracellular matrix. Here an intriguing advance in scaffold technology is noted:
Bioengineers [have] developed a gel-based sponge that can be molded to any shape, loaded with drugs or stem cells, compressed to a fraction of its size, and delivered via injection. Once inside the body, it pops back to its original shape and gradually releases its cargo, before safely degrading.
"The simplest application is when you want bulking. If you want to introduce some material into the body to replace tissue that's been lost or that is deficient, this would be ideal. In other situations, you could use it to transplant stem cells if you're trying to promote tissue regeneration, or you might want to transplant immune cells, if you're looking at immunotherapy."
Consisting primarily of alginate, a seaweed-based jelly, the injectable sponge contains networks of large pores, which allow liquids and large molecules to easily flow through it. [Researchers] demonstrated that live cells can be attached to the walls of this network and delivered intact along with the sponge, through a small-bore needle. [The] team also demonstrated that the sponge can hold large and small proteins and drugs within the alginate jelly itself, which are gradually released as the biocompatible matrix starts to break down inside the body.
Normally, a scaffold like this would have to be implanted surgically. Gels can also be injected, but until now those gels would not have carried any inherent structure; they would simply flow to fill whatever space was available. [Researchers] pushed pink squares, hearts, and stars through a syringe to demonstrate the versatility and robustness of their gel.