Rehabilitation of Achilles Tendon Injuries through Patient-Specific Scaffold Design Using FDM-Based 3D Printing of Thermoplastic Polyurethane (TPU)

Rehabilitation of Achilles Tendon Injuries through Patient-Specific Scaffold Design Using FDM-Based 3D Printing of Thermoplastic Polyurethane (TPU) | 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 Research Article Rehabilitation of Achilles Tendon Injuries through Patient-Specific Scaffold Design Using FDM-Based 3D Printing of Thermoplastic Polyurethane (TPU) Pradeep K, Mohan Kishore N S N S, Mohan Kishore N S, John Wesley Joyston This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9052509/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Achilles tendon is the strongest tendon in the human body but it is susceptible to injury because of excessive usage and degenerative alterations. The traditional methods used like autografts, allografts, and synthetic grafts have limitations that include donor site morbidity, rejection chances and poor mechanical performance. In order to beat these challenges, this paper examines how Thermoplastic Polyurethane (TPU) scaffolds produced using Fused Deposition Modeling (FDM) can be used in the repair of Achilles tendons. TPU has been chosen because of its superior performance in elasticity, toughness, fatigue resistance and biocompatibility thus making it a load bearing biomedical adhesive. AutoCAD was used to design patient-specific scaffold designs and Cura optimized them using spiral and lattice geometry. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were used to test the morphological and structural characteristics of TPU. SEM showed a rough, porous and heterogeneous surface with microcracks that promote cell adhesion and composite incorporation, and XRD proved that TPU is semi-crystalline, which shows a compromise between mechanical strength and elasticity. The hemolytic analysis revealed that there were low red blood cell lysis with the percentage of hemolysis less than 5% at lower concentrations and less than 10% at higher concentrations which categorizes TPU as non-hemolytic to slightly hemolytic. Evaluation of the cytotoxicity using the MTT assay indicated high cell viability (> 87) at all the tested concentrations, which is far beyond the ISO 10993-5 limits of safety. These results prove the outstanding hemocompatibility and non-cytotoxic nature of TPU, which makes it a potential scaffold material in tendon tissue engineering. The paper has shown that TPU scaffolds built using FDM could reach the required mechanical strength and biological safety to be used in Achilles tendon regeneration. Achilles tendon thermoplastic polyurethane (TPU) fused deposition modeling (FDM) 3D printing tissue engineering scaffold fabrication biocompatibility hemocompatibility Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 18 May, 2026 Reviews received at journal 16 May, 2026 Reviews received at journal 13 May, 2026 Reviewers agreed at journal 13 May, 2026 Reviewers agreed at journal 11 May, 2026 Reviewers agreed at journal 09 May, 2026 Reviewers agreed at journal 07 May, 2026 Reviewers invited by journal 07 May, 2026 Editor assigned by journal 18 Mar, 2026 Submission checks completed at journal 18 Mar, 2026 First submitted to journal 06 Mar, 2026 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. 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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-9052509","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":639937832,"identity":"bc9d298d-a8ca-4474-a492-4470fa83996d","order_by":0,"name":"Pradeep K","email":"","orcid":"","institution":"Chennai Institute of Technology Sarathy Nagar","correspondingAuthor":false,"prefix":"","firstName":"Pradeep","middleName":"","lastName":"K","suffix":""},{"id":639937833,"identity":"fea86383-c18b-4549-9d2b-294e6b5c32fa","order_by":1,"name":"Mohan Kishore N S N 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