04/27/2022
By Sokny Long
The Francis College of Engineering, Department of Biomedical Engineering, invites you to attend a doctoral qualifier examination by M. Adelfio on “A long-term in vitro 3D gingival tissue model to investigate host-pathogen interactions.”
Ph.D. Student: Miryam Adelfio
Defense Date: Wednesday, May 11, 2022
Time: 11 a.m.
Location: Perry Hall, 315. Faculty members or students interested in participating virtually can join by using the zoom link.
Thesis/Dissertation Title: A physiologically relevant in vitro 3D gingival tissue model to investigate host-pathogen interactions.
Committee Chair (Advisor): Chiara Ghezzi, Ph.D., Department of Biomedical Engineering, University of Massachusetts Lowell
Committee Members:
- Dr. Bryan Black, Ph.D., Department of Biomedical Engineering, University of Massachusetts Lowell
- Natalia Palacios, Ph.D., Department of Health Science, University of Massachusetts Lowell
Periodontal disease is a major health problem in the United States with a financial burden of 54 billion USD/year. Disease onset and progression are not clearly understood, nor can they be studied in human clinical models because of the complexity of identifying disease triggers, or in animal models because of differing gingival anatomic architecture and microbiome compositions. Similarly, recent bioengineering strategies failed to replicate the cytoarchitecture, dynamic complexity of the tissue and long-term host-pathogen co-culture, all necessary conditions to investigate, in a systematic approach, the trajectory of periodontitis and explore therapeutical solutions. The aim of the present work is to design a culture system to sustain the long-term in vitro culture of 3D gingival tissue. The model will subsequently be interrogated to assess host-pathogen interactions as well as to investigate potential clinical interventions. Our proposed bioreactor consisted of a biocompatible, portable chamber connected to a cost-effective peristaltic pump to support the long-term culture of the model in a closed-loop fluid circulation. Gingival tissue architecture was mimicked with a porous silk sponge populated with human primary oral stromal and keratinocyte cells. In addition, 3D-printed teeth were inserted in the scaffold to recreate the gingival sulcus depth, where host-pathogen unbalances are originated. Characterization of the silk sponge revealed a porous and permeable scaffold and thus capable of supporting long-term gingival cells growth through homogenous O2 diffusion and nutrients distribution. To replicate the oral physiological environment, we also formulated an artificial saliva that mirrored the non-Newtonian profile, viscosity, and ionic composition of human saliva. After confirming under static conditions cell viability and differentiation in artificial saliva for three weeks, we tested the fluid dynamic properties of the saliva inside the bioreactor and defined the fluid parameters of the model (inlet/outlet position, inlet velocity) by profiling shear stress through Particle Image Velocimetry (PIV) analysis. To conclude, we performed morphological, structural, and functional assessments of the tissue model grown in the dynamic regime and evaluated any differences from a static culture. Preliminary data (picoGreen, lactate dehydrogenase, immunohistochemistry and, transepithelial electrical resistance (TEER)) indicated the formation of a fully viable, differentiated, and stratified epithelium and a viable tissue construct under both static and dynamic conditions. In conclusion, we have developed a bioreactor that recapitulated the key elements of the gingival tissue (cytoarchitecture, saliva, and oral fluid dynamic). The model will then be exposed to patient-derived microbiomes (healthy versus gingivitis clinical conditions) to study host-microbiome interactions and calibrate the tissue response against clinical biomarkers from tissue exudates.
All interested students and faculty members are invited to attend in person or virtually.