Human primary cells are cells directly derived from tissue samples from patients or healthy donors. They are the truest in vitro models of human physiology and disease, therefore are invaluable in medical discovery and development. Use of human primary cells as physiology- or disease-relevant models provides significant advantages in research and development for better understanding and treatment of various human diseases, including cancer, cardiovascular and inflammatory diseases. Unfortunately, utility of precious primary cells is largely hindered by the lack of means for effective transfection with minimal side-effects, particularly in high- throughput mode. To address this unmet need, we propose the development of a SureFection technology that combines two emerging advancements in the field of cell transfection, i.e., controlled in situ electroporation and DMA nuclear delivery, to effective transfect primary cells free of biochemical side-effects. This strategy will be implemented in novel miniature devices that can be readily multiplexed to conform to 96-well slide/1536-well microplate uHT footprints, permitting massive scale in vivo gene funtion analysis, as well as drug screening and testing using primary cells. In Phase I, we will demonstrate the applicability of our technology in three primary cell systems that are important models for study of breast and prostate cancer, angiogenesis and cardiovascular disease. Our long-term goal is to combine this enabling technology with our novel functional assay methods to provide primary cell based high-throughput solutions for target ID&validation, compound screening and in vitro drug testing/profiling, as part of our strategies to facilitate faster, cheaper and safer small molecule drug development. The proposed research and development will benefit public health by forwarding our understanding of the roles of human genes in physiology and disease, and accelerating therapeutic development to fight with cancer, cardiovascular and other diseases