Building further on the goal of engineering immunity, our second major area of research is the development of synthetic materials that enhance the safety and potency of cellular and molecular immunotherapies. We have focused recently on multiple coordinated strategies to enhance cancer immunotherapy, using approaches that are also broadly applicable to infectious disease. Examples include the development of nanoparticle-based drug delivery “backpacks” for T-cells that can be used to enhance adoptive T-cell therapy of cancer, and the use of lipid nanoparticles to anchor locally-administered immunotherapy agents within tumors, for enhanced safety and efficacy of potent immunomodulators. We are also studying the properties of small nanoparticles (< 10 nm in diameter) bearing amphiphilic charged and hydrophobic surface functionalities; these nanomaterials have the capacity to strongly interact with membranes of living cells, and depending on composition and size, can embed within or pass through lipid bilayers without permanent disruption of the membrane. These novel nanomaterials may provide a new way to achieve for highly efficient delivery of drugs or diagnostic agents into cells for therapy or monitoring of cellular processes.