O2M Webinar: Carl G. Simon, Jr., Ph.D.

Measuring Cell Viability in Scaffolds

Moderated by: Dr. David S. Kaplan, Microbiologist, FDA

About the Speaker: Dr. Simon is a biologist in the Biomaterials Group at the National Institute of Standards & Technology. He earned a B.S. in Biology from Bucknell University and a Ph.D. in Biochemistry from University of Virginia where his thesis focused on signal transduction during human platelet aggregation. He trained as a post-doctoral fellow in NIST Polymers Division, and became a staff scientist at NIST in 2003. He leads projects on cell-material interactions and tissue engineering scaffolds that support the development and characterization of tissue engineered medical products. Dr. Simon is Chair of ASTM Committee F04.43 “Cells and Tissue-Engineered Constructs” where documentary standards are being advanced to support the development of medical products. Dr. Simon is active in the Society for Biomaterials and is on the editorial board for “Biomaterials” and “Journal of Biomedical Materials Research Part B”.

Webinar: In the field of tissue engineering, 3D scaffolds and cells are often combined to yield constructs that are used as therapeutics to restore tissue function in patients. Viable cells are required to achieve the intended mechanism of action for the therapeutic, where the live cells may build new tissue or may release factors that induce tissue regeneration. Thus, there is a need to be able to reliably measure cell viability in 3D scaffolds as a quality attribute of tissue-engineered medical products. Measurements of cell viability in scaffolds are challenging because the scaffold interferes with the measurement. For soluble assays, the scaffold may impede diffusion of or physically interact with soluble reaction components. For imaging, the scaffold may interfere with photons, electrons or other particles being used to probe the system. Toward addressing this need, we are developing a model scaffold-cell-assay system that has been validated for a cell viability measurement. The system is composed of a polysaccharide hydrogel seeded with Jurkat cells with measurement of moles of ATP per gram of DNA. The reproducibility of the model system will be assessed by an inter-laboratory study and the results will be used to support an ASTM standard test method. In addition, we expect that the model scaffold-cell-assay system will be useful for assessing other methods for measuring cell viability in scaffolds, such as optical coherence tomography or electron paramagnetic resonance imaging.