Now, scientists at Harvard-affiliated Brigham and Women's Hospital have found that a smaller number of stem cells can still get the job done, if they're first hopped up on steroids.

The research was conducted by Doctors Jeffrey Karp and James Ankrum, the former of whom has also helped bring us painless medical tape for newborns, worm-inspired skin grafts, porcupine quill-inspired surgical patches, and superglue for holes in the heart.

The scientists started with ordinary mesenchymal stem cells, and treated them with glucocorticoid steroids. This caused the cells to produce an increased amount of indoleamine-2,3-dioxygenase (IDO), which is an anti-inflammatory agent. Since it was noted that the cells' IDO expression was highest when they were actually being exposed to the steroids, the scientists added steroid-containing microparticles to the cells, so that they could have access to the drugs at all times.