BIOMED Seminar

Title:
Computational Modeling of Feedback Regulation in Synthetic Circuits

Speaker:
Ania-Ariadna Baetica, PhD
Assistant Professor
Department of Mechanical Engineering and Mechanics (MEM)
College of Engineering
Drexel University

Details:
Biological systems maintain homeostasis through feedback regulation, yet the quantitative principles that determine when such regulation remains effective are not fully understood. Our research developed quantitative frameworks to analyze how feedback control  shapes cellular behavior in dynamic biological systems, particularly in settings where molecular components are continuously produced, degraded, and redistributed. 

This work addressed  fundamental questions in systems biology by identifying how feedback architectures influence adaptation and the preservation of system outputs under perturbation. Using sensitivity analysis, we quantified how variation in molecular processes of production, degradation, and binding rates, alters cellular dynamics. Together, these results provide predictive strategies for interpreting regulation in living systems and for understanding how cells maintain homeostasis as internal conditions vary.

Biosketch:
Ania-Ariadna Baetica, PhD, is an Assistant Professor in the Department of Mechanical Engineering and Mechanics (MEM) and an affiliate faculty member of the School of Biomedical Engineering, Science and Health Systems at Drexel University. Dr. Baetica received her BA degree from Princeton University in 2012 and her PhD from California Institute of Technology in 2018. After receiving her doctoral degree, she was a postdoctoral scholar at the University of California at San Francisco. 

Dr. Baetica has also been serving on the Council and Membership Committee of the Engineering Biology Research Consortium since 2025. She has been leading her BioControl research group at Drexel University since 2023. Her research program focuses on two directions: one studies how feedback shapes the behavior of synthetic gene circuits using mechanistic modeling, and the other uses single-cell and immune profiling data to understand what drives long-term persistence and cytotoxicity of T cells in order to improve immunotherapies.

BIOMED PhD Thesis Defense

Title: 
Immune Checkpoint-Presenting Granular Hydrogels for T Cell Immune Modulation

Speaker:
Kenneth Kim, PhD Candidate
School of Biomedical Engineering, Science and Health Systems
Drexel University

Advisor:
Christopher Rodell, PhD 
Assistant Professor
School of Biomedical Engineering, Science and Health Systems
Drexel University 

Details:
Autoimmunity arises from the breakdown of immune tolerance, precipitating chronic inflammation and tissue damage. Current therapies rely on systemic immunosuppression, which can alleviate symptoms but can result in severe adverse drug reactions (infection, cancer). There remains a need for strategies that restore immunoregulation while minimizing adverse systemic effects; local biomaterial-based approaches for sustained immunomodulation are a promising alternative.

Many autoimmune diseases, including psoriasis, are characterized by reduced regulatory T cell (Treg) populations and increased pro-inflammatory T cell responses. While Treg-based therapies (adoptive transfer, in vivo induction) have shown potential, they are limited by phenotypic-instability, lack of targeted delivery, and off-target biodistribution. This dissertation investigates an alternative strategy to locally promote immunoregulation through sustained checkpoint ligand presentation using injectable hydrogels. 

Granular hydrogels were engineered to present the novel immune checkpoint ligand B7x. This platform exhibits shear-thinning and self-healing properties for local delivery, supports bio-orthogonal conjugation of azide-modified B7x (B7x-Az), provides a porous microstructure that enables immune cell infiltration, and enables potential co-delivery of disease-specific antigens. In vitro, B7x-Az retained Treg-inducing function. Intravital near-IR imaging demonstrated that B7x-conjugated hydrogel (Gel-B7x-Az) exhibited enhanced initial checkpoint retention and persistence compared with soluble B7x (>28 days). In a murine psoriasis model, Gel-B7x-Az elevated Treg populations, reduced γδT17/Th17 populations, and ameliorated clinical measures of disease severity.

Collectively, this work demonstrates that checkpoint-functionalized biomaterials can locally modulate immune responses to suppress inflammation. This platform is amenable to diverse immune checkpoints and co-delivery of soluble factors, offering broad therapeutic potential for autoimmune diseases, organ rejection, and tissue repair.

The School of Biomedical Engineering, Science and Health Systems is pleased to announce its 8th Annual Immune Modulation & Engineering Symposium (IMES).