Improved engraftment with nanoparticle delivery of GSK-3 inhibitor following in utero HSC transplantation. Transient exposure of HSCs to the GSK-3 inhibitor in culture prior to transplantation leads to modest engraftment in the in utero setting (A). However, encapsulation of the GSK-3 inhibitor with nanoparticles that adhere to the HSCs and release the inhibitor over time improves HSC engraftment (B). Professional illustration by Somersault18:24.