Mark Sellmyer leads the Sellmyer Lab at the Perelman School of Medicine at the University of Pennsylvania, focusing on developing molecular and cellular solutions to address significant challenges in biomedical sciences and clinical medicine. The lab specializes in imaging diagnostics, creating small molecules, engineered proteins, and cell-based tools that utilize light control in vivo, drawing from principles of chemical synthetic biology. The technologies developed in the lab are being translated to clinical applications using nuclear medicine molecular imaging techniques. The lab has pioneered preclinical testing and human applications of a new class of positron emission tomography (PET) radiotracers based on the small molecule antibiotic trimethoprim. These molecules have diverse applications across various fields, including cancer biology, immunology, and infectious disease. The lab is known for its recent publications, including contributions to the fields of molecular imaging and the clinical translation of adoptive cell therapy using PET imaging. Sellmyer's research has been recognized with the SNMMI Mars Shot Innovator's Grant, aimed at improving antibody-based radiopharmaceuticals through advanced chemistry techniques. The lab also celebrates the achievements of its students and continues to impact the field through innovative research efforts.