Injectable sponge to deliver drugs and cells inside body

Harvard researchers have developed a gel-based sponge that can be moulded to any shape, loaded with drugs or stem cells, compressed to a fraction of its size, and delivered via a jab.

Once inside the body, it pops back to its original shape and gradually releases its cargo, before safely degrading.

The bio-compatible technology amounts to a prefabricated healing kit for a range of minimally invasive therapeutic applications, including regenerative medicine.

“What we’ve created is a three-dimensional structure that you could use to influence the cells in the tissue surrounding it and perhaps promote tissue formation,” said lead researcher David J Mooney, from Harvard School of Engineering and Applied Sciences (SEAS)

“The simplest application is when you want bulking,” Mooney said. “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,” he said.

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.
Mooney and his research team 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.
They demonstrated that the sponge can hold large and small proteins and drugs within the alginate jelly itself, which are gradually released as the bio-compatible 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.

“Our scaffolds can be designed in any size and shape, and injected in situ as a safe, preformed, fully characterised, sterile, and controlled delivery device for cells and drugs,” said lead author Sidi Bencherif in a statement.