Lindsey Douglas
Pronouns: she/her/hers
Research Mentor(s): Yuji Mishina
Research Mentor School/College/Department: /
Program: RS
Session: Session 1 (9:00am – 9:50am)
Authors: W. Benton Swanson, Yuji Mishina
Abstract
Recent advances in the field of tissue engineering suggest the specific design of a biomaterial can direct cells towards specific regenerative fates. Our lab has previously demonstrated that poly (L-lactic acid) scaffold pore size has a significant effect on cell differentiation in the context of bone regeneration. Our data suggests that sufficiently large pore scaffolds (> 250 um diameter) facilitate bone formation, while sufficiently small pores (<125 um diameter) maintain stemness of cells. These findings propose that a triphasic (large-small-large, LSL) scaffold, a small pore region flanked by large pore regions, might be able to act as a stem cell reservoir, supplying the scaffold with a renewable source of stem cells. I believe this configuration is ideal for tissue regeneration because the center small pore region serves as a stem cell niche and when they start to differentiate, cells migrate to the flanking large pore regions to form bones. Thus, my first attempt was to investigate if this microenvironment could induce cell migration across the scaffold depending on their differentiation status, or if it kept the cells in the same general place. Our hypothesis is that if we seed differentiated cells in the center small pore region, they will migrate into the large pore areas to form bone at the tissue-scaffold interface over time. Specifically, this study sought to determine whether differentiated cells migrated faster and farther across the triphasic scaffold than undifferentiated stem cells. We compared how differentiated and undifferentiated cells traveled in three different microenvironments: a large pore scaffold, a triphasic (LSL) scaffold with uniform-seeding, and a triphasic (LSL) scaffold with center-seeding. The differentiated and undifferentiated cells were labeled with green and red fluorescent markers, respectively. Using a confocal microscope, we were able to take 3D images of the cells’ position on the LSL scaffold and measure their migration distance from the small-large pore boundary in millimeters. The results of this experiment suggested no significant difference in the migration distance of uniformly-seeded differentiated and undifferentiated cells on the LSL scaffolds. However, LSL scaffolds with center-seeded cells showed a significant difference in differentiated vs undifferentiated cell movement across the scaffold. Compared to the undifferentiated cells they were seeded with who stayed in the small pore region, center-seeded differentiated cells traveled farther across the scaffold and into the large pore region. This experiment has been repeated at several different time points to gain additional spatio-temporal resolution: 24 hours, 72 hours, 1 week, and 2 weeks. While the data from these additional experiments is still being processed, we expect to see differentiated cells migrating out farther to the large pore areas of the triphasic scaffold than undifferentiated cells.
