Speaker
Description
Introduction
Although cellularized biomaterial constructs have significantly advanced tissue repair and regenerative medicine, their clinical translation remains limited due to labor-intensive preparation processes and inadequate shelf-life. Therefore, creating modular, shelf-ready, cellularized products with long-term preservation capability and immediate clinical utility is critically needed. In this study, we developed an innovative cryopreservable microtissue platform, featuring engineered biomaterial interfaces that support extended cryostorage (over six months). These internal interfaces significantly improve cellular proliferation, and regenerative performance compared with conventional hydrogel constructs. This modular microtissue approach simplifies clinical workflows, enabling rapid, on-demand, injectable or bioprintable applications.
Materials and Methods
We designed modular cryopreserved microtissues utilizing a novel two-step “freeze-then-crosslink” cryo-gelation strategy. Following prolonged cryostorage exceeding seven months, we characterized post-thaw cellular viability, proliferation rates, injectability, and 3D-bioprinting performance. The regenerative potential was validated in vivo through rat models involving subcutaneous implantation and critical-sized skull defect regeneration.
Results
The modular microtissues preserved exceptional cell viability (>85%, human mesenchymal stem cell) after seven months of cryopreservation. Internal biomaterial interfaces significantly improved cellular viability, proliferation, and overall regenerative function, compared to conventional granular mictogels lacking internal interfaces. Specifically, the presence of internal interfaces markedly accelerated biomolecule penetration within the microtissues, achieving over 90% of the peak diffusion density within approximately 10 seconds. In contrast, conventional microgels scaffolds showed substantially slower permeation rates, typically requiring tens of seconds or even minutes to reach approximately 50% of the peak level. Additionally, these modular microtissues were successfully demonstrated as injectable therapeutic formulations and high-resolution bioinks. Their injectability allowed efficient minimally invasive delivery, and precise 3D bioprinting was successfully performed, indicating strong potential for fabricating complex tissues. Animal studies, including subcutaneous implantation and critical-sized skull defect repair in rats, further confirmed that the microtissues effectively promoted tissue regeneration, validating the positive role of the internal biomaterial interfaces.
Discussion
In this study, we address key limitations in current cell-based regenerative therapies by developing an innovative, modular, and cryopreservable microtissue platform. Our design integrates engineered biomaterial interfaces at the microscale, enabling effective long-term preservation with excellent cellular viability and functional outcomes upon thawing. Importantly, this modular approach supports sustained cellular growth across diverse clinical applications, from minimally invasive injections to precision biofabrication. By significantly simplifying clinical workflows, our platform provides a versatile, accessible, and truly shelf-ready cell therapy solution. This technology holds great promise as a readily available product for both research and clinical applications, particularly in personalized medicine, where patient-derived microtissues can facilitate tailored therapeutic strategies.
Conclusions
In this study, we developed a cryopreserved, interface-incorporated microtissue platform that enables long-term storage, robust cell growth, personalized minimally invasive injection, and rapid on-demand biofabrication for regenerative medicine.
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