Bennet, T. J. | Search bioRxiv

bioRxiv2026

Effects of MRI on an Injectable Hydrogel with Magnetically Alignable Microstructures for Oriented Cell Growth

Injectable biomaterials with aligned microstructures play a critical role in tissue engineering and drug-delivery applications where control over the position and orientation of cells and nano/micron-scale architectures enhance intervention efficacy. Patients are often subject to MRI scans; for patient safety and treatment efficacy, we investigated the effects of MRI on a biomaterial treatment consisting of aligned magnetic microstructures being developed for guiding cell growth. Under MRI exposure, potential movement of aligned structures could be detrimental to nearby cells, and potential MRI-induced heating could adversely affect traumatized tissue. In this work, the alignment state and heat conduction of such a treatment were studied using a 9.4 T preclinical MRI. The treatment comprises short magnetic rod-shaped polycaprolactone fibers (rods) with embedded magnetic nanoparticles in a surrounding hydrogel (gelatin methacrylate), with rod alignment observed before and after a 45-minute MRI scan. No change in rod alignment state was observed, and no heat generation was measured. A theoretical framework was developed which supports the experimental observation that the biomaterial is stable under MRI. This work can be extended to other biomaterial systems with aligned architectures used in tissue engineering applications such as spinal cord, muscle and tendon.

bioengineering↗

bioRxiv2025

Engineering a Multilayer Microfluidic Airway-On-A-Chip with Tunable GelMA Hydrogel for Physiologically Relevant Aerosol Exposure Studies

Climate change-driven increases in forest fires pose a major global health risk due to exposure to smoke containing hazardous gases and fine particulates, emphasizing the need for physiologically relevant in vitro airway models for studying smoke-induced responses. Microfluidic lung-on-a-chip technologies provide a strong foundation for in vitro airway modeling and ongoing developments are expanding their ability to incorporate multicellular organization, extracellular matrix complexity, and physiologically relevant exposure methods. This work presents the optimization and integration of a photopolymerizable gelatin methacrylate (GelMA)-based hydrogel into a microfluidic airway-on-a-chip that models the human small conducting airways and supports controlled aerosol exposure to wood smoke. The GelMA hydrogel was optimized to support fibroblast encapsulation, endothelial, and epithelial adhesion and robust mechanical stability. The device combines the hydrogel with a compartmentalized microchannel layout, and sacrificial molding to create a 3D organotypic airway culture featuring a multilayer architecture, 3D stromal matrix, and a perfusable vasculature-like lumen. Coupling the platform with a custom aerosol exposure system enables precise, biomimetic exposure to whole wood smoke. Proof-of-concept studies using transforming growth factor beta1 (TGF-{beta}1) and whole wood smoke elicited expected inflammatory and fibrotic responses, validating the platforms physiological relevance for inhalation studies and investigating smoke-induced airway remodeling and inflammation.

bioengineering↗