{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T05:17:25Z","timestamp":1787894245530,"version":"build-2784847793"},"reference-count":31,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T00:00:00Z","timestamp":1787702400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science KAKENHI","doi-asserted-by":"crossref","award":["15K06547"],"award-info":[{"award-number":["15K06547"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science KAKENHI","doi-asserted-by":"crossref","award":["24K21704"],"award-info":[{"award-number":["24K21704"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Engineering volumetric three-dimensional tissues requires the rapid establishment of dense, capillary-like microchannels to ensure adequate oxygen and nutrient supply while preventing hypoxic cell necrosis. Sacrificial microfiber templating approaches using lower critical solution temperature (LCST) polymers cannot employ type I collagen hydrogels\u2014a biologically ideal extracellular matrix\u2014because LCST fiber dissolution in cold collagen solutions precedes matrix gelation owing to thermodynamic mismatch. Here, we present a proof-of-concept strategy to rapidly fabricate capillary-sized microchannels within collagen hydrogels using thermoresponsive, physically crosslinked gelatin microfibers as sacrificial templates. Three-dimensional gelatin microfibers with capillary-sized diameters (approximately 10 \u03bcm) were fabricated via wet spinning and embedded in a type I collagen aqueous solution (4 \u00b0C). Open microchannels throughout the collagen matrix were successfully generated within 1 h of sequential thermal incubation (20 \u00b0C for collagen gelation and subsequently 37 \u00b0C for gelatin thermal dissolution), without cytotoxic chemicals. Active particle flow confirmed channel patency and fluidic continuity. Additionally, heparinized rat blood readily perfused through the channels, and scanning electron microscopy revealed open microchannel cross-sections (diameter: approximately 10 \u03bcm). This simple, thermally controlled approach resolves the limited temperature compatibility between collagen matrices and sacrificial microfibers, serving as a promising biofabrication foundation for engineering tissue constructs.<\/jats:p>","DOI":"10.3390\/ma19173630","type":"journal-article","created":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T15:04:32Z","timestamp":1787756672000},"page":"3630","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Rapid Fabrication of Capillary-Sized Microchannels in Collagen Hydrogel via Thermally Responsive Gelatin Microfiber Templates"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7985-1649","authenticated-orcid":false,"given":"Takayuki","family":"Takei","sequence":"first","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Momoka","family":"Nakamura","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ko","family":"Nishimura","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saki","family":"Kobaru","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshihiro","family":"Ohzuno","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masahiro","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3223","DOI":"10.1021\/nl102184c","article-title":"Nanotechnology in drug delivery and tissue engineering: From discovery to applications","volume":"10","author":"Shi","year":"2010","journal-title":"Nano Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1111\/j.1749-6632.2001.tb03854.x","article-title":"An approach to constructing three-dimensional tissue","volume":"944","author":"Ko","year":"2001","journal-title":"Ann. 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