A compact micro-load compression testing device for stiffness characterization of soft biological tissues

A compact micro-load compression testing device for stiffness characterization of soft biological tissues | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article A compact micro-load compression testing device for stiffness characterization of soft biological tissues Hikaru Nakao, Kazuyo Ito, Gen Hayase, Daisuke Yoshino This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8525668/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Mechanical stiffness is a critical physical property of soft biological tissues that is closely associated with physiological and pathological states. However, the quantitative mechanical characterization of small and soft samples remains challenging due to the limited sensitivity and poor portability of conventional compression testing systems. Here, we present a compact, benchtop micro-load compression testing platform designed for the evaluation of small, soft biological tissues. The device enables reproducible measurements under millinewton-level loading and micrometer-scale displacement while maintaining a simple, portable configuration. Using collagen- and gelatin-based gel samples with spherical and cylindrical geometries as biomimetic models, we demonstrate the system's performance across different materials, temperatures, and sample geometries. To address the predominance of nonlinear deformation in soft materials, we introduce a model-free stiffness index, which is defined as the local slope of the semi-logarithmic nominal stress–strain relationship. This approach allows for a robust relative comparison of mechanical responses without assuming specific constitutive models or material homogeneity. The proposed platform combines practical operability with analytical robustness, providing a versatile tool for the rapid mechanical screening of soft tissues and biomimetic materials. Its compact design and compatibility with controlled environments make it ideal for applications that require the flexible, high-sensitivity mechanical assessment of limited, fragile biological samples. Biological sciences/Biological techniques Biological sciences/Biotechnology Physical sciences/Engineering Physical sciences/Materials science Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformationNakaoIto2025revised.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8525668","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":574183153,"identity":"e24b8bab-1ebd-4776-8ef9-fbdb713e529f","order_by":0,"name":"Hikaru Nakao","email":"","orcid":"","institution":"Tokyo University of Agriculture and Technology","correspondingAuthor":false,"prefix":"","firstName":"Hikaru","middleName":"","lastName":"Nakao","suffix":""},{"id":574183154,"identity":"51377a5b-0f01-4c15-b9ac-72eaed457c54","order_by":1,"name":"Kazuyo Ito","email":"","orcid":"","institution":"Tokyo University of Agriculture and 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