{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:31:42Z","timestamp":1785403902286,"version":"3.56.0"},"reference-count":32,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T00:00:00Z","timestamp":1780358400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32271396"],"award-info":[{"award-number":["32271396"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32071357"],"award-info":[{"award-number":["32071357"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52273138"],"award-info":[{"award-number":["52273138"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["32271396"],"award-info":[{"award-number":["32271396"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"award":["32071357"],"award-info":[{"award-number":["32071357"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"award":["52273138"],"award-info":[{"award-number":["52273138"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"111 Project of Introducing Talents of Discipline to Universities, China","award":["B16033"],"award-info":[{"award-number":["B16033"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Cell culture is foundational to biomedical advancements, yet its widespread clinical and practical distribution is severely constrained by the high infrastructural costs of cryogenic logistics and the physical stressors of liquid-phase transit. Herein, we propose a proof-of-concept cryogen-free cell transportation strategy leveraging a rapid reversible thermoresponsive collagen (RRTC) hydrogel regulated by simulated body fluid (SBF). Operating via temperature-driven physical network assembly and disassembly rather than chemical crosslinking or chemical modifications, the RRTC system undergoes a rapid sol-to-gel transition within 60 s at 37 \u00b0C for efficient cell encapsulation, and completely reverses to a free-flowing sol state within 60 s at 4 \u00b0C to facilitate enzyme-free, non-destructive cell retrieval. Using L929 fibroblasts as a standardized benchmarking cell model, the biophysical protection of the matrix was systematically evaluated under both static simulated transit (48 h and 120 h) and real-world trans-city courier transportation (an approximate 50 h round trip via SF Express) within a passively temperature-shield configuration. The SBF-regulated 3D physical confinement successfully shielded cells from manual handling, multi-axis shipping vibrations, and environmental thermal fluctuations. Post-transport evaluations demonstrated that the encapsulated cells maintained a high viability above 90% and a stable recovery yield of approximately 78%, while exhibiting robust subsequent 2D re-adhesion and sustained re-culture capacity. This thermoresponsive matrix provides a potential matrix for short-term cryogen-free cell transportation and post-transport recovery, while further studies using additional cell types, longer transportation periods, and functional assays are required to evaluate its broader applicability.<\/jats:p>","DOI":"10.3390\/gels12060488","type":"journal-article","created":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T12:45:08Z","timestamp":1780404308000},"page":"488","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Reversible Sol\u2013Gel Transition in Thermoresponsive Collagen Hydrogels for Cryogen-Free Cell Logistics"],"prefix":"10.3390","volume":"12","author":[{"given":"Junjie","family":"Wang","sequence":"first","affiliation":[{"name":"National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, No. 29 Wangjiang Road, Chengdu 610065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Ju","sequence":"additional","affiliation":[{"name":"National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, No. 29 Wangjiang Road, Chengdu 610065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1461-8111","authenticated-orcid":false,"given":"Yang","family":"Lei","sequence":"additional","affiliation":[{"name":"Institute of Biomedical Innovation, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, No. 1299, Xuefu Road, Honggutan District, Nanchang 330031, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2827-3487","authenticated-orcid":false,"given":"Jieyu","family":"Zhang","sequence":"additional","affiliation":[{"name":"National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, No. 29 Wangjiang Road, Chengdu 610065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2412-6762","authenticated-orcid":false,"given":"Yunbing","family":"Wang","sequence":"additional","affiliation":[{"name":"National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, No. 29 Wangjiang Road, Chengdu 610065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.cell.2020.03.001","article-title":"The emerging landscape of immune cell therapies","volume":"181","author":"Weber","year":"2020","journal-title":"Cell"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1093\/ilar.41.4.187","article-title":"Mechanisms of cryoinjury in living cells","volume":"41","author":"Gao","year":"2000","journal-title":"ILAR J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.actbio.2021.07.001","article-title":"Advanced biomaterials in cell preservation: Hypothermic preservation and cryopreservation","volume":"131","author":"Ma","year":"2021","journal-title":"Acta Biomater."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1159\/000149797","article-title":"Hypothermic injury: The mitochondrial calcium, ATP and ROS love-hate triangle out of balance","volume":"22","author":"Brinkkoetter","year":"2008","journal-title":"Cell. 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