UC Riverside

Optical microscopy is an essential tool in biological research, drug discovery, and medical diagnosis. Yet it harbors limitations in resolution, penetration depth, photobleaching, and multiplexity. Various strategies, including new techniques and novel probes, are developed to address those drawbacks and improve performance. With that in mind, this dissertation presents our work of designing peptide-based probes for advanced optical bioimaging applications. Our first study reports a cyclic peptide identified from a library screening against terbium(III) (Tb3+) ions. It can bind to Tb3+ and enhance Tb3+ luminescence by 150 times through antenna effects. The second study describes a peptide-based linker for photoactive immunofluorescence with iterative cleavage (PACIFIC). It is compatible with both fixed cells and formalin-fixed paraffin-embedded (FFPE) tissue sections for highly multiplex protein imaging. In the final study, we demonstrate the application of PACIFIC integrated with live-cell imaging. By investigating dynamic properties and phenotypical features in a glioblastoma cell line, we obtain a more comprehensive understanding of the cell motility. Overall, our work showcases how peptide-based modalities can be explored for advanced optical imaging and expanded applications.