Lectures on Advanced Materials, Bioimaging and Diagnostics

Welcome to two exciting lectures courtesy of the Center for Sustainable STEM Education! The lectures should be of broad interest for chemists, materials scientists, nanoscientists, medical scientists and engineers. All – especially students – are welcome!

Lecture 1: High-Performance Luminescent Materials Using Structural Constraint. Stability under excitation is critical to nearly all applications of luminescent materials. Nonradiative decay pathways that cause photobleaching or decomposition limit the usefulness of organic semiconductors in electronics, bioimaging, and photocatalysts. Here we describe new pi-conjugated systems with locked planarity designed to limit nonradiative decay. We use s-heptazines and imidazoacridines as strong electron acceptors, and azatriangulenes as electron donors to give materials exhibiting thermally activated delayed fluorescence (TADF), room-temperature phosphorescence, and two-photon absorption. These materials exhibit reduced photobleaching, large two-photon cross-sections and photoluminescence quantum yields near 100%. We also use scanning tunneling microscopy on Ag(111) to probe the electronic interactions of these materials on surfaces. This lecture will also describe the use of TADF materials in luminescent nanoparticles for bioimaging, and as photocatalysts for high-energy organic transformations useful to drug discovery campaigns. This lecture covers the following work: 1) J. Am. Chem. Soc. 2023, 145, 18366; 2) Adv. Opt. Mater. 2023, 11, 2202754; 3) Adv. Funct. Mater. 2022, 32, 2204087; 4) Chem. Mater. 2022, 34, 2624; 5) Chem. Sci. 2022, 13, 2296; 6) J. Am. Chem. Soc. 2021, 143, 16976.

Lecture 2. Luminescent Polymer Nanoparticles for Diagnostics and Imaging. Smartphones are now ubiquitous, and are more common than clean drinking water in some developing countries and remote communities. Where healthcare resources are limited, there is a need for diagnostic tools that are both inexpensive and readily available. Fluorescent polymer nanoparticles – termed polymer dots, or Pdots, have recently been shown to have sufficient brightness to be visible by a smartphone camera for fluoresence-based assays. In this lecture, the design and synthesis of new multifunctional Pdot probes for use in bioanalysis as diagnostic tools will be described. Pdots with near-infrared fluorescence capable of selective binding to breast cancer cells suitable for imaging in the biological transparency window (650 – 1350 nm) will be demonstrated. New Pdot technologies taking advantage of thermally activated delayed fluorescence (TADF) for time-gated imaging will also be described, allowing one to eliminate background fluorescence from biological tissues or secondary dyes. We will also show how single-chain polymer nanoparticles (SCPNs) can be used to give Pdots that can deliver a targeted drug payload with high specificity. Deep-red fluorescent polymer dots functionalized with a cell-penetrating peptide mimic will also be described, capable of entering a variety of mammalian cells with low cytotoxicity for time-gated imaging. This lecture covers the following work: 1) Angew. Chem. Int. Ed. 2021, 60, 18630; 2) J. Am. Chem. Soc. 2021, 143, 13342; 3) J. Am. Chem. Soc. 2021, 143, 16976; 4) ACS Appl. Mater. Interfaces 2020, 12, 20000; 5) Angew. Chem. Int. Ed. 2024, 63, e202400712.

Zachary M. Hudson is an Associate Professor and Canada Research Chair in Sustainable Chemistry at the University of British Columbia. Zac completed his B.Sc. at Queen’s University in Kingston, Ontario. He remained at Queen’s to pursue a Ph.D. in Inorganic Chemistry with Prof. Suning Wang, also holding graduate fellowships at Jilin University in China with Yue Wang and Nagoya University in Japan with Shigehiro Yamaguchi. He then moved to the University of Bristol as a Marie Curie Postdoctoral Fellow with Prof. Ian Manners, followed by a second Postdoctoral Fellowship at the California Nanosystems Institute at the University of California, Santa Barbara with Prof. Craig Hawker. He joined the faculty at UBC in 2015, where he holds the Canada Research Chair in Sustainable Chemistry. His research program develops luminescent materials for optoelectronics, bioimaging, and photocatalysis. Recent awards for his work include the ACS Herman Mark Award in Polymer Science, the Polymer International IUPAC Award, the Killam Teaching Award, and most recently the Charles McDowell Medal for UBC’s top researcher under 40 in science and engineering.