Tunable bioadhesive with modulus-independent non-fibrotic tissue interfaces
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liu-jiayiliu-sm-meche-2025-thesis.pdf
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49.83 MB
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4edd918b6cb5b20bca5617bf458f598b
Author(s)
Liu, Jiayi
Advisor(s)
Zhao, Xuanhe
Date Issued
September 2025
Publisher
Massachusetts Institute of Technology
Abstract
Implantable medical devices (IMDs) are essential for treating a wide range of medical conditions. Their long-term performance is often hindered by the foreign body reaction (FBR), an immune reaction characterized by inflammation and subsequent fibrotic encapsulation. Material properties such as surface charge, roughness, and stiffness have been shown to significantly influence host immune responses and fibrosis. In particular, prior studies indicate that fibrosis-activated, mechanoresponsive myofibroblasts deposit more collagen on stiffer substrates. To investigate whether adhesion can bypass this stiffness-dependent fibrotic encapsulation, we introduce a bioadhesive hydrogel composed of a poly(acrylic acid) double network, with stiffness tunable over two orders of magnitude, from 26 kPa to 1 MPa. After implantation in mice, these adhesive implants exhibited limited fibrotic encapsulation after two and four weeks. For all stiffness considered, histology and immunofluorescence analysis demonstrated recruitment of innate immune cells at the interface, without subsequent myofibroblast accumulation. These findings highlight tissue adhesion as a critical design parameter for implantable biomaterials to mitigate FBR and guarantee long-term, nonfibrotic integration across a wide stiffness range.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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