Joshua Kritzer
Professor
Tufts University
Talk Information
Strategies for Membrane Permeability or Oral Bioavailability
16 June 2025, 09:35am - 10:00am, in the Pacific Jewel Ballroom
L06 – Chemical Biology Approaches for Measuring Intracellular Drug Delivery
Professor Joshua A. Kritzer is a Professor of Chemistry at Tufts University, where he leads the Kritzer Lab in the Department of Chemistry. His interdisciplinary research combines organic synthesis, biochemistry, biophysics, computational design, genetics, and cell biology to develop novel molecules addressing critical chemical and biomedical challenges.
Academic Background
Dr. Kritzer earned his B.E. in Chemical Engineering from The Cooper Union in 2000 and his Ph.D. in Biophysical Chemistry from Yale University in 2005. He completed postdoctoral research at Yale before joining the faculty at Tufts University, where he has established a distinguished career in chemical biology.
Research Focus
The Kritzer Lab focuses on the discovery and application of new molecules to solve vital chemical and biomedical problems. The lab utilizes peptide and peptidomimetic libraries to explore nontraditional modes of action, aiming to bypass limitations of small molecule screening. By integrating techniques from organic synthesis, biophysical chemistry, molecular biology, and genetics, the lab develops new molecules and strategies to address diseases such as cancer, inflammation, and autoimmune disorders.
Notable Contributions
Dr. Kritzer has made significant contributions to the field of chemical biology, particularly in the development of the Chloroalkane Penetration Assay, CAPA) a versatile assay for measuring cell penetration of therapeutic molecules. His work has advanced the understanding of peptide and peptidomimetic interactions with protein surfaces, leading to the development of novel therapeutic strategies for various diseases.
Awards and Honors
Professor Kritzer has been recognized for his innovative research with several awards, including the Sanofi Innovation Award, which supports his work in developing approaches for treating neurodegenerative diseases like Alzheimer's.
Professional Engagements
Beyond his research, Dr. Kritzer is actively involved in mentoring students and contributing to the academic community. He serves on various committees and collaborates with interdisciplinary teams to advance the field of chemical biology.
Through his innovative research and dedication to education, Professor Joshua A. Kritzer continues to make significant contributions to the fields of chemistry and biomedical science.
Chemical Biology Approaches for Measuring Intracellular Drug Delivery
Department of Chemistry, Tufts University, Medford, Massachusetts, USA
Large-molecule therapeutics including peptides, oligonucleotides, and proteins make up a large and growing portion of the drug development pipeline. One of the greatest barriers to developing these drugs is cell penetration. Most enter the cell through a complex pathway involving endocytosis followed by endosomal escape. This process is so poorly understood and difficult to study that it is challenging simply to measure how much compound has actually accessed the cytosol at any given point.
The Kritzer Lab has developed new tools for making these and related measurements. The Chloroalkane Penetration Assay (CAPA) is a versatile assay that measures cell penetration using cellularly expressed HaloTag protein and a small chloroalkane tag on the molecule-of-interest. CAPA has been used by the Kritzer group to measure cell penetration for many classes of peptide and oligonucleotide therapeutics, to measure penetration to different subcellular compartments, and to measure relative penetration in different cell types. CAPA has also been adopted by academic and industrial groups all over the world to investigate cell penetration.
The Kritzer group has also used molecular evolution to produce new HaloTag variants which work optimally with a fluorogenic benzothiadiazole dye. The resulting “BenzoTag” system allows for turn-on, no-wash cell labeling in seconds. BenzoTag is currently being applied to produce a “turn-on” version of CAPA for continued investigation of drug delivery and mechanisms of endosomal escape.