Abstract We are requesting funding to purchase a LUMICKS C-Trap optical tweezer and confocal fluorescence microscope. This instrument will greatly expand the ability to perform mechanical measurements of single molecules and cells at the University of Rochester. These services will be made available to a user base extending throughout the University of Rochester and Western New York. Mechanical measurements of single molecules and cells greatly advance our understanding of fundamental biological processes such as cell motility, transcription, and protein folding. However, optical tweezers are frequently custom-designed, making it difficult for non- specialists to adapt these techniques to their system of interest. The LUMICKS C-Trap will remove this barrier by providing a versatile microfluidic delivery system and user-friendly software that will serve as a single integrated platform for applying a wide range of mechanical forces, precisely detecting nm-scale structural transitions, and measuring the emission of multiple fluorophores concurrently. Dr. Elio Abbondanzieri, a pioneer in the field of optical tweezers, will assist users in designing assays tailored to their scientific questions. The broad range of measurements that can be performed with this instrument will be utilized by our diverse initial user group covering a wide range of scientific topics including phase-separated condensates from bacteria, regulation of translation, CRISPR tool development, cell migration, chromatin structure, and organelle motility. This group includes researchers from the University of Rochester River Campus, University of Rochester Medical Center, and Rochester Institute of Technology. Although the initial users have varied interests, a common theme is that they have scientific questions that cannot be addressed with instruments currently available on campus. The LUMICKS C-Trap is thus ideally suited to function as a state-of-the-art resource that enables current and future investigators to further the goals of their NIH-funded research.