The liver is one of the body’s hardest-working organs, carrying out hundreds of vital jobs, from filtering toxins and metabolizing medications to producing proteins essential for blood clotting. Yet when it fails, the only definitive treatment is often a transplant, a solution limited by a chronic shortage of donor organs.

MIT engineers have now developed injectable “mini livers” that, in mice, survived for at least two months while performing many of the functions of healthy liver tissue.

“We think of these as satellite livers. If we could deliver these cells into the body, while leaving the sick organ in place, that would provide booster function,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT, and a member of MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science (IMES).