The document summarizes the author's recent research focusing on three directions: (1) studying the structures and functions of fibrinolytic proteins and developing inhibitors for them, (2) determining the structures of cell surface receptors and human serum albumin, and (3) developing a fluorescent probe for biomedical imaging, cancer therapy, and antimicrobial applications by conjugating it to targeting peptides. The author has determined several protein crystal structures and developed peptide inhibitors for proteases involved in cancer metastasis. The fluorescent probe conjugates show tumor targeting capability in mouse models and effectiveness against drug resistant bacteria.