{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T05:16:53Z","timestamp":1787894213267,"version":"build-2784847793"},"reference-count":37,"publisher":"MDPI AG","issue":"9","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\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32171312"],"award-info":[{"award-number":["32171312"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["32171312"],"award-info":[{"award-number":["32171312"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"crossref","award":["21620339"],"award-info":[{"award-number":["21620339"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100021171","name":"Guangdong Basic and Applied Basic Research Foundation","doi-asserted-by":"crossref","award":["2022A1515110181"],"award-info":[{"award-number":["2022A1515110181"]}],"id":[{"id":"10.13039\/501100021171","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Key Areas Research and Development Program of Guangzhou","award":["202103030003"],"award-info":[{"award-number":["202103030003"]}]},{"name":"Key Areas Research and Development Program of Guangzhou","award":["2023B03J1241"],"award-info":[{"award-number":["2023B03J1241"]}]},{"name":"Industry-University-Research Foundation of the Ministry of Education","award":["2023GY053"],"award-info":[{"award-number":["2023GY053"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Injectable fillers that combine immediate volume restoration with a sustained biological response remain of considerable interest in minimally invasive aesthetic medicine. In this study, a hydroxyapatite-loaded methacrylated recombinant type III collagen microgel (HAp@rhCol III-MA) was prepared by in situ coprecipitation and photocrosslinking. Recombinant type III collagen (rhCol III) was functionalized with methacryloyl groups to obtain rhCol III-MA, after which a calcium phosphate phase was mineralized in the presence of the modified collagen and the collagen phase was crosslinked under ultraviolet irradiation. More than 80% of the microgel particles prepared at 900 rpm were 20\u201380 \u03bcm in diameter. Spectroscopic, elemental, thermal, and diffraction analyses supported the incorporation of a poorly crystalline, HAp-compatible calcium phosphate phase, while rheological measurements showed higher storage and loss moduli than those of rhCol III-MA gel. HAp@rhCol III-MA did not reduce NIH-3T3 cell viability at the tested concentrations and enhanced HUVEC scratch closure and tube-network formation in vitro. Following subcutaneous implantation in rats, the microgel retained more volume than rhCol III-MA during the early and intermediate observation periods, with residual volumes of 56.58 \u00b1 3.03 mm3 for HAp@rhCol III-MA and 52.80 \u00b1 1.79 mm3 for rhCol III-MA at day 59; the commercial type I collagen comparator retained 123.23 \u00b1 2.80 mm3. The composite caused no evident tissue injury and was associated with progressive collagen deposition and a low, declining CD68-positive response. These findings support further investigation of HAp@rhCol III-MA as an injectable dermal-filling material, while long-term persistence and clinical injection performance remain to be established.<\/jats:p>","DOI":"10.3390\/gels12090762","type":"journal-article","created":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T10:59:23Z","timestamp":1787741963000},"page":"762","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Injectable Hydroxyapatite-Reinforced Methacrylated Recombinant Type III Collagen Microgels for Soft-Tissue Filling"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-7730-7521","authenticated-orcid":false,"given":"Qianqian","family":"Zhu","sequence":"first","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-0686-286X","authenticated-orcid":false,"given":"Cuicui","family":"Wu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xi","family":"Luo","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shihao","family":"Dong","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Beijuan","family":"Luo","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Changcheng","family":"Yin","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhuangzhuang","family":"Cai","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shunqing","family":"Tang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"48515","DOI":"10.1002\/app.48515","article-title":"Polymeric injectable fillers for cosmetology: Current status, future trends, and regulatory perspectives","volume":"137","author":"Zhao","year":"2020","journal-title":"J. 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