Cell transplants are currently tested for neurological and other degenerative disorders, but to survive, transplanted stem cells need specific local growth factors that cannot be administered orally or intravenously. In October Nature Biotechnology Melissa Mahoney and Mark Saltzman from Cornell University, Ithaca, New York describe a technique that can re-create the specific stem cell microenvironment around the transplanted fetal cells in the brain — enabling efficient cell differentiation and histogenesis.

Mahoney & Saltzman assembled fetal stem cells with cell-adhesive and controlled-release microparticles to form transplantable neo-tissues, which mimic the microenvironment of developing tissue. They found that this transplantation system allowed control of several important variables such as growth factor dose, spatial positioning of growth factor sources and molecular signals at the cell surface.

To prove that the system worked, Mahoney & Saltzman demonstrated that nerve growth factor (NGF) delivered via synthetic microenvironments increased levels of neuronal cholinergic activity in...