Dr. Chen is the Peter J. W. Debye Professor in the Department of Chemistry and Chemical Biology at Cornell University. His group has pioneered the development and application of single-molecule fluorescence microscopy for studying catalysis on individual nanoparticles at the single-turnover resolution and nanometer precision. Understanding the structure-activity correlation of nanoparticles is important for developing better catalysts, but hampered by their inherent inhomogeneity. Dr. Chen’s single-molecule microscopy work has uncovered heterogeneous reaction pathways and differential selectivity among individual nanoparticles, as well as their temporal catalytic dynamics. He has discovered surprisingly complex spatial activity patterns within a single crystal facet on a single catalyst particle. He has further developed the single-molecule microscopy approach for scalable, parallel screening of nanoparticle catalytic activity. Moreover, his group pioneered the application of single-molecule fluorescence microscopy in bioinorganic chemistry, in particular on metal homeostatic proteins. He has discovered new mechanisms in metalloregulator-DNA interactions and gained insight into multi-body protein interactions involving metallochaperones.