Multi-modal Characterization of Polymeric Gels to Determine the Influence of Testing Method on Observed Elastic Modulus

Abstract

Demand for materials that mechanically replicate native tissue has driven development and characterization of various new biomaterials. However, a consequence of materials and characterization technique diversity is a lack of consensus within the field, with no clear way to compare values measured via different modalities. This likely contributes to the difficulty in replicating findings across the research community; recent evidence suggests that different modalities do not yield the same mechanical measurements within a material, and direct comparisons cannot be made across different testing platforms. Herein, we examine whether "material properties" are characterization modality-specific by analyzing the elastic moduli determined by five typical biomaterial mechanical characterization techniques: unconfined-compression, tensiometry, rheometry, and micro-indentation at the macroscopic level, and microscopically using nanoindentation. These analyses were performed in two different polymeric gels frequently used for biological applications, polydimethylsiloxane (PDMS) and agarose. Each was fabricated to span a range of moduli, from physiologic to supraphysiologic values. All five techniques identified the same overall trend within each material group, supporting their ability to appreciate relative moduli differences. However, significant differences were found across modalities, illustrating a difference in absolute moduli values, and thereby precluding direct comparison of measurements from different characterization modalities. These observed differences may depend on material compliance, viscoelasticity, and microstructure. While determining the underlying mechanism(s) of these differences was beyond the scope of this work, these results demonstrate how each modality affects the measured moduli of the same material, and the sensitivity of each modality to changes in sample material composition.

Department(s)

Chemical and Biochemical Engineering

Comments

National Institutes of Health, Grant C30606GG

International Standard Serial Number (ISSN)

1878-0180; 1751-6161

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

01 Apr 2019

PubMed ID

30703738

Link to Full Text

Share

 
COinS