{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T18:13:10Z","timestamp":1783015990021,"version":"3.54.6"},"reference-count":44,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,5,25]],"date-time":"2024-05-25T00:00:00Z","timestamp":1716595200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the National Natural Science Foundation of China","award":["81571832"],"award-info":[{"award-number":["81571832"]}]},{"name":"the National Natural Science Foundation of China","award":["2018225082"],"award-info":[{"award-number":["2018225082"]}]},{"name":"the National Natural Science Foundation of China","award":["HZHB2018013"],"award-info":[{"award-number":["HZHB2018013"]}]},{"name":"the Key Research &amp; Development Project of Liaoning Province","award":["81571832"],"award-info":[{"award-number":["81571832"]}]},{"name":"the Key Research &amp; Development Project of Liaoning Province","award":["2018225082"],"award-info":[{"award-number":["2018225082"]}]},{"name":"the Key Research &amp; Development Project of Liaoning Province","award":["HZHB2018013"],"award-info":[{"award-number":["HZHB2018013"]}]},{"name":"the 2018 Scientist Partners of China Medical University (CMU) and Shenyang Branch of Chinese Academy of Sciences (CAS)","award":["81571832"],"award-info":[{"award-number":["81571832"]}]},{"name":"the 2018 Scientist Partners of China Medical University (CMU) and Shenyang Branch of Chinese Academy of Sciences (CAS)","award":["2018225082"],"award-info":[{"award-number":["2018225082"]}]},{"name":"the 2018 Scientist Partners of China Medical University (CMU) and Shenyang Branch of Chinese Academy of Sciences (CAS)","award":["HZHB2018013"],"award-info":[{"award-number":["HZHB2018013"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Vascularized organs hold potential for various applications, such as organ transplantation, drug screening, and pathological model establishment. Nevertheless, the in vitro construction of such organs encounters many challenges, including the incorporation of intricate vascular networks, the regulation of blood vessel connectivity, and the degree of endothelialization within the inner cavities. Natural polymeric hydrogels, such as gelatin and alginate, have been widely used in three-dimensional (3D) bioprinting since 2005. However, a significant disparity exists between the mechanical properties of the hydrogel materials and those of human soft tissues, necessitating the enhancement of their mechanical properties through modifications or crosslinking. In this study, we aim to enhance the structural stability of gelatin\u2013alginate hydrogels by crosslinking gelatin molecules with oxidized pullulan (i.e., a polysaccharide) and alginate molecules with calcium chloride (CaCl2). A continuous small-diameter vascular network with an average outer diameter of 1 mm and an endothelialized inner surface is constructed by printing the cell-laden hydrogels as bioinks using a coaxial 3D bioprinter. The findings demonstrate that the single oxidized pullulan crosslinked gelatin and oxidized pullulan\/CaCl2 double-crosslinked gelatin\u2013alginate hydrogels both exhibit a superior structural stability compared to their origins and CaCl2 solely crosslinked gelatin\u2013alginate hydrogels. Moreover, the innovative gelatin and gelatin\u2013alginate hydrogels, which have excellent biocompatibilities and very low prices compared with other hydrogels, can be used directly for tissue\/organ construction, tissue\/organ repairment, and cell\/drug transportation.<\/jats:p>","DOI":"10.3390\/gels10060366","type":"journal-article","created":{"date-parts":[[2024,5,27]],"date-time":"2024-05-27T09:33:31Z","timestamp":1716802411000},"page":"366","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Formation of Stable Vascular Networks by 3D Coaxial Printing and Schiff-Based Reaction"],"prefix":"10.3390","volume":"10","author":[{"given":"Jingxin","family":"Shan","sequence":"first","affiliation":[{"name":"Center of 3D Printing & Organ Manufacturing, School of Intelligent Medicine, China Medical University (CMU), No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China"},{"name":"Department of Biomedical Engineering, He University, Shenyang 110163, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhiyuan","family":"Kong","sequence":"additional","affiliation":[{"name":"Center of 3D Printing & Organ Manufacturing, School of Intelligent Medicine, China Medical University (CMU), No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China"},{"name":"Guangdong Key Lab of Orthopedic Technology and Implant Materials, General Hospital of Southern Theater Command of PLA, Guangzhou 510010, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaohong","family":"Wang","sequence":"additional","affiliation":[{"name":"Center of 3D Printing & Organ Manufacturing, School of Intelligent Medicine, China Medical University (CMU), No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, China"},{"name":"Key Laboratory for Advanced Materials Processing Technology, Ministry of Education & Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,5,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s40883-015-0006-z","article-title":"Regenerative Engineering: Approaches to limb regeneration and other grand challenges","volume":"1","author":"Laurencin","year":"2015","journal-title":"Regen. Eng. Transl. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1089\/ten.teb.2011.0553","article-title":"Progress in the tissue engineering and stem cell industry \u201cAre we there yet?\u201d","volume":"18","author":"Jaklenec","year":"2012","journal-title":"Tissue Eng. Part B Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1159\/000336876","article-title":"Vascularization in tissue engineering: Angiogenesis versus inosculation","volume":"48","author":"Laschke","year":"2012","journal-title":"Eur. Surg. Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1126\/science.2934816","article-title":"A blood vessel model constructed from collagen and cultured vascular cells","volume":"231","author":"Weinberg","year":"1986","journal-title":"Science"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1177\/0883911507078386","article-title":"A new polyurethane\/heparin vascular graft for small-caliber vein repair","volume":"22","author":"Yan","year":"2007","journal-title":"J. Bioact. Compat. Polym."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1177\/0883911507088271","article-title":"Rapid prototyping of polyurethane for the creation of vascular systems","volume":"23","author":"Xu","year":"2008","journal-title":"J. Bioact. Compat. Polym."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"aau6934","DOI":"10.1126\/scitranslmed.aau6934","article-title":"Bioengineered human acellular vessels recellularize and evolve into living blood vessels after human implantation","volume":"11","author":"Kirkton","year":"2019","journal-title":"Sci. Transl. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5864","DOI":"10.1016\/j.biomaterials.2005.02.027","article-title":"Fabrication of viable tissue-engineered constructs with 3D cell-assembly technique","volume":"26","author":"Yan","year":"2005","journal-title":"Biomaterials"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1177\/0883911505053658","article-title":"Direct Construction of a Three-dimensional Structure with Cells and Hydrogel","volume":"20","author":"Yan","year":"2005","journal-title":"J. Bioact. Compat. Polym."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1177\/0963689718809918","article-title":"Bioartificial organ manufacturing technologies","volume":"28","author":"Wang","year":"2018","journal-title":"Cell Transplant."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Jiao, W., Li, X., Shan, J., and Wang, X. (2022). Study of several alginate-based hydrogels for in vitro 3D cell cultures. Gels, 8.","DOI":"10.3390\/gels8030147"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Jiao, W., Liu, C., Shan, J., Kong, Z., and Wang, X. (2022). Construction and evaluation of small-diameter bioartificial arteries based on a combined-mold technology. Polymers, 14.","DOI":"10.3390\/polym14153089"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Liu, F., and Wang, X. (2020). Synthetic polymers for organ 3D printing. Polymers, 12.","DOI":"10.3390\/polym12081765"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Liu, T., Yang, B., Tian, W., Zhang, X., and Wu, B. (2022). Cryogenic coaxial printing for 3D shell\/core tissue engineering scaffold with polymeric shell and drug-loaded core. Polymers, 14.","DOI":"10.3390\/polym14091722"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"45904","DOI":"10.1021\/acsami.0c14871","article-title":"3D Bioprinting-tunable small-diameter blood vessels with biomimetic biphasic cell layers","volume":"12","author":"Zhou","year":"2020","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1586\/erd.11.27","article-title":"Design properties of hydrogel tissue-engineering scaffolds","volume":"8","author":"Zhu","year":"2011","journal-title":"Expert Rev. Med. Devices"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1016\/j.tibtech.2007.08.010","article-title":"Rapid prototyping as a tool for manufacturing bioartificial livers","volume":"25","author":"Wang","year":"2007","journal-title":"Trends Biotechnol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1111\/j.1525-1594.2012.01499.x","article-title":"Intelligent freeform manufacturing of complex organs","volume":"36","author":"Wang","year":"2012","journal-title":"Artif. Organs"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"664","DOI":"10.1007\/s12015-019-09893-4","article-title":"Gelatin methacrylate (GelMA)-based hydrogels for cell transplantation: An effective strategy for tissue engineering","volume":"15","author":"Xiao","year":"2019","journal-title":"Stem Cell Rev. Rep."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1016\/j.pharmthera.2016.03.013","article-title":"Three-dimensional culture systems in cancer research: Focus on tumor spheroid model","volume":"163","author":"Nath","year":"2016","journal-title":"Pharmacol. Ther."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Wang, X., Ao, Q., Tian, X., Fan, J., Tong, H., Hou, W., and Bai, S. (2017). Gelatin-based hydrogels for organ 3D bioprinting. Polymers, 9.","DOI":"10.3390\/polym9090401"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1021\/bm990017d","article-title":"Structural and rheological properties of methacrylamide modified gelatin hydrogels","volume":"1","author":"Bogdanov","year":"2000","journal-title":"Biomacromolecules"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"4140","DOI":"10.1002\/fsn3.1282","article-title":"The modification of gelatin films: Based on various cross-linking mechanism of glutaraldehyde at acidic and alkaline conditions","volume":"7","author":"Lin","year":"2019","journal-title":"Food Sci. Nutr."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1675","DOI":"10.1021\/bm900036s","article-title":"Evaluation of cross-linking methods for electrospun gelatin on cell growth and viability","volume":"10","author":"Sisson","year":"2009","journal-title":"Biomacromolecules"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1002\/term.492","article-title":"Characterization of chitosan-gelatin scaffolds for dermal tissue engineering","volume":"7","author":"Tseng","year":"2013","journal-title":"J. Tissue Eng. Regen. Med."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1163\/156856200743670","article-title":"Cross-linking and characterisation of gelatin matrices for biomedical applications","volume":"11","author":"Kuijpers","year":"2000","journal-title":"J. Biomater. Sci. Polym. Ed."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e2497","DOI":"10.7717\/peerj.2497","article-title":"Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells","volume":"4","author":"Yang","year":"2016","journal-title":"PeerJ"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Skopinska-Wisniewska, J., Tuszynska, M., and Olewnik-Kruszkowska, E. (2021). Comparative study of gelatin hydrogels modified by various cross-linking agents. Materials, 14.","DOI":"10.3390\/ma14020396"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1592","DOI":"10.1016\/j.ijbiomac.2020.07.264","article-title":"Fabrication and characterization of collagen-oxidized pullulan scaffold for biomedical applications","volume":"164","author":"Selvakumar","year":"2020","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"121912","DOI":"10.1016\/j.carbpol.2024.121912","article-title":"Multifunctional polysaccharide\/metal\/polyphenol double-crosslinked hydrogel for infected wound","volume":"332","author":"Duan","year":"2024","journal-title":"Carbohydr. Polym."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e2002931","DOI":"10.1002\/smll.202002931","article-title":"Crosslinking strategies for 3D bioprinting of polymeric hydrogels","volume":"16","author":"Nejad","year":"2020","journal-title":"Small"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.carbpol.2019.04.004","article-title":"Pullulan dialdehyde crosslinked gelatin hydrogels with high strength for biomedical applications","volume":"216","author":"Zhang","year":"2019","journal-title":"Carbohydr. Polym."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1016\/j.ijpharm.2017.08.004","article-title":"Redox sensitive cationic pullulan for efficient gene transfection and drug retention in C6 glioma cells","volume":"530","author":"Priya","year":"2017","journal-title":"Int. J. Pharm."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Pelin, I.M., Popescu, I., Calin, M., Rebleanu, D., Voicu, G., Ionita, D., Zaharia, M.-M., Constantin, M., and Fundueanu, G. (2023). Tri-component hydrogel as template for nanocrystalline hydroxyapatite deposition using alternate soaking method for bone tissue engineering applications. Gels, 9.","DOI":"10.3390\/gels9110905"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"24209","DOI":"10.1021\/acsami.3c04390","article-title":"Quaternary pullulan-functionalized 2D MoS(2) glycosheets: A potent bactericidal nanoplatform for efficient wound disinfection and healing","volume":"15","author":"Roy","year":"2023","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Sun, J., Gong, Y., Xu, M., Chen, H., Shao, H., and Zhou, R. (2024). Coaxial 3D bioprinting process research and performance tests on vascular scaffolds. Micromachines, 15.","DOI":"10.3390\/mi15040463"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Ottenbrite, R.M. (2010). Biomedical Applications of Hydrogels Handbook, Springer.","DOI":"10.1007\/978-1-4419-5919-5"},{"key":"ref_38","first-page":"26","article-title":"Comparison of the potential for bioprinting of different 3D printing technologies","volume":"9","year":"2023","journal-title":"Int. J. Bioprinting"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1039\/C4BM00234B","article-title":"In vitro study of directly bioprinted perfusable vasculature conduits","volume":"3","author":"Zhang","year":"2015","journal-title":"Biomater. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.carbpol.2014.04.060","article-title":"Synthesis, characterization and solution behaviour of oxidized pullulan","volume":"111","author":"Spatareanu","year":"2014","journal-title":"Carbohydr. Polym."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Chen, Q., Tian, X., Fan, J., Tong, H., Ao, Q., and Wang, X. (2020). An interpenetrating alginate\/gelatin network for three-dimensional (3D) cell cultures and organ bioprinting. Molecules, 25.","DOI":"10.3390\/molecules25030756"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1177\/0883911509102794","article-title":"Controlled adipose-derived stromal cells differentiation into adipose and endothelial cells in a 3D structure established by cell-assembly technique","volume":"24","author":"Xu","year":"2009","journal-title":"J. Bioact. Compat. Polym."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3868","DOI":"10.1016\/j.biomaterials.2010.01.111","article-title":"An cell-assembly derived physiological 3D model of the metabolic syndrome, based on adipose-derived stromal cells and a gelatin\/alginate\/fibrinogen matrix","volume":"31","author":"Xu","year":"2010","journal-title":"Biomaterials"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Schneemann, M., Gerhard, R., Schulzke, J.-D., and B\u00fccker, R. (2023). CDT of Clostridioides difficile Induces MLC-Dependent Intestinal Barrier Dysfunction in HT-29\/B6 Epithelial Cell Monolayers. Toxins, 15.","DOI":"10.3390\/toxins15010054"}],"container-title":["Gels"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2310-2861\/10\/6\/366\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:48:52Z","timestamp":1760107732000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2310-2861\/10\/6\/366"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,5,25]]},"references-count":44,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2024,6]]}},"alternative-id":["gels10060366"],"URL":"https:\/\/doi.org\/10.3390\/gels10060366","relation":{},"ISSN":["2310-2861"],"issn-type":[{"value":"2310-2861","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,5,25]]}}}