The product that will result from the proposed STTR application from Sunstone Biosciences and the University of Pennsylvania is a novel labeled antibody-based reagent kit that can be used to rapidly identify diverse red blood cell phenotypes prior to blood transfusion. At present, pre-transfusion blood typing involves only the major antigens of the ABO and Rh groups, and relies on the use of a largely- manual hemagglutination reaction. The time- and labor-intensiveness of this procedure limits the number of RBC sub-groups that can be tested prior to a transfusion, risking the development of sensitization of patients who receive multiple transfusions throughout their life. We plan to develop a large panel of RBC antigen-specific MAbs, labeled with rare-earth nanophosphors, able to rapidly determine RBC phenotype using a wide range of common and rare antigens in an automatable, multiplexed assay format. The programmable, and narrow optical spectra of rare-earth crystals are ideal for generating molecular detection systems that are capable of vastly greater multiplexing than conventional optical probes. At the end of Phase 2 of the proposed program, we anticipate having designed and constructed a panel of approximately 20 or more antibodies, each with a unique optical emission signal, that can be used to create a revolutionary blood phenotyping "signature". The upconverting characteristics of the nanocrystals are unique identifiers of target-specific labeling and quantification. Other methods of molecular detection, including Quantum Dots and conventional fluorophores, are utilized widely throughout the research community but possess many limitations such as photobleaching, poor resolution, and the limited number of samples permitted to run simultaneously. Rare-earth phosphor nanocyrstals address these problems, as inert, stable light emitters that allow for high resolution and vastly multiplexed imaging. PUBLIC HEALTH RELEVANCE: Sunstones Biosciences has, with its consortium partners at Princeton University, generated preliminary evidence that nanocrystals as small as ~10 nm can be synthesized, that these nanocrystals retain their unique optical properties, and that they can be coated for functionalization (such as for conjugation to antibodies). In this Phase 1 proposal, we will extend these studies to generate and test at least three phosphor nanocrystal-labeled antibodies specific for RBC antigens. This proposal will reduce the incidence of allergic reactions and other side-effects of blood transfusion by developing a new product for comprehensively matching donor and recipient blood types. Unlike conventional methods for blood typing, the proposed method will allow rapid detection of even rare blood markers.