This microscopic landscape serves as both recruiting office and training ground for disease-fighting cells. Engineers have created a porous membrane scaffold that can be pre-loaded with the necessary biological and chemical agents to stimulate the body’s natural repair and defense capacities. Cells can be programmed to perform particular tasks by layering the membrane with different polymers to change the microenvironment in which the cells interact. Already used for tissue regeneration, this biodegradable device provides a new platform for delivering drugs and empowering cells to fight cancer.