Student: Kiera Croland

Project: Characterizing Cell-Material Interactions When Chemical Cues are Presented Locally to Human Mesenchymal Stem Cells

Poster: Vertical (PDF) | Horizontal (PDF)

Institution: Lehigh University

Major: Chemical and Biomolecular Engineering

Advisor: Kelly Schultz


Wound healing is a complex process which coordinates several cell types using chemical signals. Human mesenchymal stem cells (hMSCs) are central to coordinating the  wound healing process. Implantable materials which deliver additional hMSCs to the wound improve healing outcomes. In vivo, hMSCs are signaled to wounds by soluble proteins called cytokines, including transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α). These cytokines affect the secretions that hMSCs use to remodel their microenvironment. Therefore, these cytokines impact the delivery of cells out of the scaffold to the wound. In this work, we encapsulate hMSCs in poly(ethylene glycol) based hydrogels and uniformly tether TGF-β or TNF-α to the network. Cytokines are thiolated so that they can be tethered into the network during photopolymerization. In future work, tethered TGF-β and TNF-ɑ will be presented to hMSCs in a gradient or step change to direct cell motility. The presence of cytokines in the hydrogel is confirmed using an enzyme-linked immunosorbent substrate assay. Multiple particle tracking microrheology (MPT) is used to measure cell-mediated hydrogel degradation in response to cytokines. Using MPT, we measure that tethering cytokines to the network does not affect the material structure during enzymatic degradation in the absence of cells. MPT measurements around untreated hMSCs show little remodeling directly around cells and increasing degradation as the distance from the cell increases. Understanding how TGF-β and TNF-α affect hMSC behavior improves the design of cell delivery scaffolds that can be implanted to deliver additional cells to enhance wound healing.

Kiera Croland

About Kiera Croland

Kiera Croland is a senior studying chemical & biomolecular engineering at Lehigh University. For her senior thesis, she is involved in research on the design of implantable biomaterials for wound healing applications in the lab of Professor Kelly M. Schultz. She was the recipient of the Forum Student Research Grant in 2019 for her research on fabricating non-uniform stiffness hydrogels for directed cell motility. Prior to her senior year she served as a Residential Advisor (RA) and co-oped at Sanofi Pasteur in their Process Technology team on their Influenza, Meningitis, and COVID-19 vaccine. After graduating from Lehigh she plans to continue her studies in graduate school.