Johns Hopkins Medicine scientists have designed a blue light-guided  system to steer immune cells, a tool that could potentially be used to guide  immune cells to the location of an infection or a developing cancer. The  researchers reported their findings in the journal Developmental Cell.
To steer immune cells, the scientists genetically engineered  human neutrophils, a type of white blood cell that fights infections, and  macrophages, immune cells that engulf and absorb foreign, dead or damaged  cells.
They engineered the cells to produce cryptochrome, a  flavonoid compound found in many plants, which is activated by blue light. When  scientists shined the blue light in laboratory dishes containing the immune  cells, the light triggered a cascade of molecular signals and growth factors  inside the cell, including Ras and AKT proteins.
With the changes to signals and growth factors in the immune  cells, the scientists also found alterations to the immune cell’s cytoskeleton  (a type of scaffolding that gives cells their shape) and its polarity (the  cell’s shape and organization of intracellular materials). Within minutes, the  immune cells were following and moving toward the blue light source.
Johns Hopkins release