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RESEARCH ARTICLE

Core-shell MgO-loaded zinc-crosslinked hydrogel microspheres for immunomodulatory bone regeneration

Fang Cao1† ,  Guoshuang Zheng2† ,  Junlei Li1 ,  Zhihua Cheng1 ,  Guangxiao Yin1 ,  Liqun Song1 ,  Zhijie Ma1 ,  Jiawei Ying1 ,  Lu Li1 ,  Ke Yang3 ,  Dewei Zhao1*
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1 Department of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning , China
2 Department of Central Laboratory, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning , China
3 Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning , China
†These authors contributed equally to this work.
IJB, 026380409 https://doi.org/10.36922/IJB026380409
Received: 16 September 2026 | Revised: 13 October 2026 | Accepted: 14 October 2026 | Published online: 14 October 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Alginate hydrogel microspheres are attractive as localized ion-delivery matrices for bone regeneration, but rapid ion exchange in physiological media can destabilize the network and produce an early release pulse. Here, MgO-loaded, Zn2+-crosslinked alginate cores were coated with chitosan (CS) to form core-shell MgO@ZnSA/CS hydrogel microspheres by electrospraying and electrostatic deposition. The resulting polyelectrolyte-complex shell reduced swelling, slowed degradation, and prolonged Mg2+ and Zn2+ release while providing a cell-adhesive interface. Two MgO contents were evaluated alongside Ca-crosslinked and Zn-crosslinked controls. In vitro, all formulations supported bone marrow mesenchymal stem cell viability. The low-MgO formulation (LoMgO@ZnMs) produced the greatest alkaline phosphatase staining, matrix mineralization, Runt-related transcription factor 2 expression, and osteogenic gene expression among the tested groups. In RAW264.7 macrophages cultured without inflammatory pre-stimulation, Zn-containing formulations increased arginase-1 and Il4/Il10 and reduced inducible nitric oxide synthase and Il6/Tnfα, consistent with a shift toward a pro-regenerative marker profile; LoMgO@ZnMs generally showed the strongest response. In a rat critical-sized calvarial defect model, LoMgO@ZnMs generated the highest new-bone indices and the most continuous mineralized tissue after eight weeks. These findings identify chitosan-shelled, MgO-loaded zinc-alginate hydrogel microspheres as a sustained ion-delivery platform with dose-dependent osteogenic and immunomodulatory activity for non-load-bearing bone regeneration.

Graphical abstract
Keywords
Alginate hydrogel Microspheres
Chitosan
Magnesium oxide nanoparticles
Zinc crosslinking
Sustained ion release
Osteoimmunomodulation
Bone regeneration
Funding
This work was supported by the Liaoning Provincial Science and Technology Plan Joint Program-Natural Science Foundation-Doctoral Research Start-up Project (Grant No. 2024-BSLH-018) and General Project (Grant No. 2025-MSLH-033). This work was also supported by the Clinical Collaborative Project of Integrated Traditional Chinese and Western Medicine for Major Difficult and Complicated Diseases (Grant No. ZDYN-2024-A-137).
Conflict of interest
The authors declare no competing interests.
References
  1. Zhang T, Wei Q, Zhou H, et al. Three-dimensional-printed individualized porous implants: a new "implant-bone" interface fusion concept for large bone defect treatment. Bioact Mater. 2021;6(11):3659-3670. doi: 10.1016/j.bioactmat.2021.03.030
  2. Miron RJ, Bohner M, Zhang Y, Bosshardt DD. Osteoinduction and osteoimmunology: emerging concepts. Periodontol 2000. 2024;94(1):9-26. doi: 10.1111/prd.12519
  3. Chen R, Hao Z, Wang Y, et al. Mesenchymal stem cell-immune cell interaction and related modulations for bone tissue engineering. Stem Cells Int. 2022;2022:7153584. doi: 10.1155/2022/7153584
  4. Tomić SL, Babić Radić MM, Vuković JS, Filipović VV, Nikodinovic-Runic J, Vukomanović M. Alginate-based hydrogels and scaffolds for biomedical applications. Mar Drugs. 2023;21(3):177. doi: 10.3390/md21030177
  5. Song K, Yan X, Li S, et al. Preparation and detection of calcium alginate/bone powder hybrid microbeads for in vitro culture of ADSCs. J Microencapsul. 2015;32(8):811-819. doi: 10.3109/02652048.2015.1094533
  6. Liu Y, Liu S, Du J, et al. Mechanism and regulatory strategy study on promoting vascularized bone regeneration via intracellular zinc ion transport. Bioact Mater. 2025;53:875-892. doi: 10.1016/j.bioactmat.2025.07.020
  7. Yang B, Yao H, Yang J, Chen C, Shi J. Construction of a two-dimensional artificial antioxidase for nanocatalytic rheumatoid arthritis treatment. Nat Commun. 2022;13(1):1988. doi: 10.1038/s41467-022-29735-1
  8. Molenda M, Kolmas J. The role of zinc in bone tissue health and regeneration—a review. Biol Trace Elem Res. 2023;201(12):5640-5651. doi: 10.1007/s12011-023-03631-1
  9. Goh CH, Heng PWS, Chan LW. Alginates as a useful natural polymer for microencapsulation and therapeutic applications. Carbohydr Polym. 2012;88(1):1-12. doi: 10.1016/j.carbpol.2011.11.012
  10. Nie X, Shi Y, Wang L, Abudureheman W, Yang J, Lin C. Study on the mechanism of magnesium calcium alloys/mineralized collagen composites mediating macrophage polarization to promote bone repair. Heliyon. 2024;10(9):e30279. doi: 10.1016/j.heliyon.2024.e30279
  11. Zhou H, He Z, Cao Y, et al. An injectable magnesium-loaded hydrogel releases hydrogen to promote osteoporotic bone repair via ROS scavenging and immunomodulation. Theranostics. 2024;14(9):3739-3759. doi: 10.7150/thno.97412
  12. Babu S, Shanmugavadivu A, Lekhavadhani S, Selvamurugan N. Magnesium-based composite scaffolds for therapeutic delivery in bone tissue engineering: current advances and emerging frontiers. J Magnes Alloys. 2026;18:102029. doi: 10.1016/j.jma.2026.102029
  13. Liang X, Chen S, Liang Y, et al. Alginate-based hydrogels: recent progress in preparation, property tuning, and multifunctional applications. Gels. 2026;12(2):182. doi: 10.3390/gels12020182
  14. Sangeetha K, Girija EK. Tailor made alginate hydrogel for local infection prophylaxis in orthopedic applications. Mater Sci Eng C Mater Biol Appl. 2017;78:1046-1053. doi: 10.1016/j.msec.2017.04.154
  15. Atma Y, Sadeghpour A, Murray BS, Goycoolea FM. Chitosan-alginate polyelectrolyte complexes for encapsulation of low molecular weight fish bioactive peptides. Food Hydrocoll. 2025;160:110789. doi: 10.1016/j.foodhyd.2024.110789
  16. Fernández JM, Molinuevo MS, McCarthy AD, Cortizo AM. Strontium ranelate stimulates the activity of bone-specific alkaline phosphatase: interaction with Zn2+ and Mg2+. Biometals. 2014;27(3):601-607. doi: 10.1007/s10534-014-9733-8
  17. Park KH, Choi Y, Yoon DS, Lee KM, Kim D, Lee JW. Zinc promotes osteoblast differentiation in human mesenchymal stem cells via activation of the cAMP-PKA-CREB signaling pathway. Stem Cells Dev. 2018;27(16):1125-1135. doi: 10.1089/scd.2018.0023
  18. Pan X, Ou M, Lu Y, Nie Q, Dai X, Liu O. Immunomodulatory zinc-based materials for tissue regeneration. Biomater Adv. 2023;152:213503. doi: 10.1016/j.bioadv.2023.213503
  19. Chen Y, Sheng W, Lin J, et al. Magnesium oxide nanoparticle coordinated phosphate-functionalized chitosan injectable hydrogel for osteogenesis and angiogenesis in bone regeneration. ACS Appl Mater Interfaces. 2022;14(6):7592-7608. doi: 10.1021/acsami.1c21260
  20. Leedy MR, Martin HJ, Norowski PA, Jennings JA, Haggard WO, Bumgardner JD. Use of chitosan as a bioactive implant coating for bone-implant applications. In: Advances in Polymer Science. Berlin, Germany: Springer Berlin Heidelberg; 2011:129-165. doi: 10.1007/12_2011_115
  21. López-Valverde N, López-Valverde A, Cortés MP, Rodríguez C, Macedo De Sousa B, Aragoneses JM. Bone quantification around chitosan-coated titanium dental implants: a preliminary study by micro-CT analysis in jaw of a canine model. Front Bioeng Biotechnol. 2022;10:858786. doi: 10.3389/fbioe.2022.858786
  22. Liu M, Zhu J, Song X, Wen Y, Li J. Smart hydrogel formed by alginate-g-poly(N-isopropylacrylamide) and chitosan through polyelectrolyte complexation and its controlled release properties. Gels. 2022;8(7):441. doi: 10.3390/gels8070441
  23. Semeraro F, Herrera Millar VR, Aidos L, et al. Beyond biomaterials: engineering bioactive hydrogels as immuno-mechanobiological niches for osteochondral regeneration. Gels. 2025;11(8):658. doi: 10.3390/gels11080658
  24. Bektas C, Mao Y. Hydrogel microparticles for bone regeneration. Gels. 2023;10(1):28. doi: 10.3390/gels10010028
  25. Xin Y, Zhao N, Wang Y. Multiple roles of Runt-related transcription factor-2 in tooth eruption: bone formation and resorption. Arch Oral Biol. 2022;141:105484. doi: 10.1016/j.archoralbio.2022.105484
  26. Fu X, Li Y, Huang T, et al. Runx2/Osterix and zinc uptake synergize to orchestrate osteogenic differentiation and citrate containing bone apatite formation. Adv Sci (Weinh). 2018;5(4):1700755. doi: 10.1002/advs.201700755
  27. Qi H, Liu Y, Wu L, et al. MicroRNA-16, via FGF2 regulation of the ERK/MAPK pathway, is involved in the magnesium-promoted osteogenic differentiation of mesenchymal stem cells. Oxid Med Cell Longev. 2020;2020:1-14. doi: 10.1155/2020/3894926
  28. Kaur K, Murphy CM. Advances in the development of nano-engineered mechanically robust hydrogels for minimally invasive treatment of bone defects. Gels. 2023;9(10):809. doi: 10.3390/gels9100809
  29. Wang X, Zhang X, Gu L, et al. Porous-interconnected cell microspheres-based 3D bioprinting of vascularized high-cell-density tissues with channel-pore networks. Chem Eng J. 2026;536:176083. doi: 10.1016/j.cej.2026.176083
  30. Chen Z, Feng Y, Wang Y, et al. Dexamethasone-loaded PLGA porous microspheres used as 3D-bioprinted bioink promote tissue-engineered cartilage regeneration. Int J Bioprint. 2024;10(5):3396. doi: 10.36922/ijb.3396
  31. Zhang G, Song E, Yu P, et al. Three-dimensional-printed hydrogel scaffolds with neuregulin-1 sustained-release microspheres for enhanced dedifferentiation and myelin regeneration in peripheral nerve injury. Int J Bioprint. 2025;11(5):154-177. doi: 10.36922/IJB025170168
  32. Qiang L, Huang H, Shan J, et al. 3D-printed zinc/magnesium-doped hydroxyapatite-polycaprolactone composite scaffolds for angiogenesis and osteogenesis. Int J Bioprint. 2024;10(6):4243. doi: 10.36922/ijb.4243
  33. Hu X, Hu Q, Liu S, Zhang H. Synergy of engineered gelatin methacrylate-based porous microspheres and multicellular assembly to promote osteogenesis and angiogenesis in bone tissue reconstruction. Int J Biol Macromol. 2024;283(pt 1):137228. doi: 10.1016/j.ijbiomac.2024.137228
  34. Zheng L, Li M, Liang C, Zu W, Zhao Y. Development of a 3D-printed polycaprolactone/magnesium phosphate composite scaffold functionalized with novel antimicrobial peptides for enhanced bone defect regeneration. Int J Bioprint. 2025;11(3):277-291. doi: 10.36922/IJB025080060
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International Journal of Bioprinting, Electronic ISSN: 2424-8002 Print ISSN: 2424-7723, Published by AccScience Publishing
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