Prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections

Abstract

Osteomyelitis is a devastating disease caused by microbial infection in deep bone tissue. Its high recurrence rate and impaired restoration of bone deficiencies are major challenges in treatment. Microbes have evolved numerous mechanisms to effectively evade host intrinsic and adaptive immune attacks to persistently localize in the host, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants (SCVs). Moreover, microbial-mediated dysregulation of the bone immune microenvironment impedes the bone regeneration process, leading to impaired bone defect repair. Despite advances in surgical strategies and drug applications for the treatment of bone infections within the last decade, challenges remain in clinical management. The development and application of tissue engineering materials have provided new strategies for the treatment of bone infections, but a comprehensive review of their research progress is lacking. This review discusses the critical pathogenic mechanisms of microbes in the skeletal system and their immunomodulatory effects on bone regeneration, and highlights the prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections. It will inform the development and translation of antimicrobial and bone repair tissue engineering materials for the management of bone infections.

References

1. Zhang, S.et al.Immunomodulatory biomaterials against bacterial infections: progress, challenges, and future perspectives. The Innovation 4, 100503 (2023).
2. Zelmer A. R., Nelson R., Richter K.& Atkins, G. J. Can intracellular Staphylococcus aureus in osteomyelitis be treated using current antibiotics? A systematic review and narrative synthesis. Bone Res. 10, 53(2022).
3. Masters, E. A.et al.Evolving concepts in bone infection: redefining “biofilm”, “acute vs. chronic osteomyelitis”, “the immune proteome” and “local antibiotic therapy”. Bone Res. 7, 20(2019).
4. Zalavras C. G.& Patzakis, M. J. Open fractures: evaluation and management. J. Am. Acad. Orthop. Surg. 11, 212-219 (2003).
5. Metsemakers, W. J.et al. Infection after fracture fixation: current surgical and microbiological concepts. Injury 49, 511-522 (2018).
6. Schwarz, E. M.et al.2018 International consensus meeting on musculoskeletal infection: research priorities from the general assembly questions. J. Orthop. Res. 37, 997-1006 (2019).
7. Ramage G., Tunney M. M., Patrick S., Gorman, S. P. & Nixon, J. R. Formation of propionibacterium acnes biofilms on orthopaedic biomaterials and their susceptibility to antimicrobials. Biomaterials 24,3221-3227 (2003).
8. Veis D. J.& Cassat, J. E. Infectious osteomyelitis: marrying bone biology and microbiology to shed new light on a persistent clinical challenge. J. Bone Miner. Res. 36, 636-643 (2021).
9. Conterno L. O.& Turchi, M. D. Antibiotics for treating chronic osteomyelitis in adults. Cochrane Database Syst. Rev. https://doi.org/10.1002/14651858.CD004439.pub3 (2013).
10. Calhoun, J., Manring, M. M.& Shirtliff, M. Osteomyelitis of the long bones. Semin. Plast. Surg. 23, 059-072 (2009).
11. Fantoni, M., Taccari, F.& Giovannenze, F. Systemic antibiotic treatment of chronic osteomyelitis in adults. Eur. Rev. Med. Pharmacol. Sci. 23, 258-270 (2019).
12. Calhoun J. H.& Manring, M. M. Adult osteomyelitis. Infect. Dis. Clin. North Am. 19, 765-786 (2005).
13. Cui, Y.et al.Dual-functional composite scaffolds for inhibiting infection and promoting bone regeneration. Mater. Today Bio. 16, 100409(2022).
14. Xiong, Y.et al.The role of the immune microenvironment in bone, cartilage, and soft tissue regeneration: from mechanism to therapeutic opportunity. Mil. Med. Res. 9, 65(2022).
15. Salhotra A., Shah H. N., Levi B.& Longaker, M. T. Mechanisms of bone development and repair. Nat. Rev. Mol. Cell Biol. 21, 696-711 (2020).
16. Wang X., Wang Z., Fu J., Huang K.& Xie, Z. Induced membrane technique for the treatment of chronic hematogenous tibia osteomyelitis. BMC Musculoskelet. Disord. 18, 33(2017).
17. Tong, K.et al. Masquelet technique versus Ilizarov bone transport for reconstruction of lower extremity bone defects following posttraumatic osteomyelitis. Injury 48, 1616-1622 (2017).
18. Khare, D., Basu, B.& Dubey, A. K. Electrical stimulation and piezoelectric biomaterials for bone tissue engineering applications. Biomaterials 258, 120280 (2020).
19. Pacheco, H.et al. Tissue engineering scaffold for sequential release of vancomycin and rhBMP2 to treat bone infections: release of vancomycin and rhBMP2 to treat bone infections. J. Biomed. Mater. Res. A 102, 4213-4223 (2014).
20. Xie, C. M.et al. Silver nanoparticles and growth factors incorporated hydroxyapatite coatings on metallic implant surfaces for enhancement of osteoinductivity and antibacterial properties. ACS Appl. Mater. Interfaces 6, 8580-8589 (2014).
21. Lian, X.et al.Antibacterial and biocompatible properties of vancomycin-loaded nano-hydroxyapatite/collagen/poly (lactic acid) bone substitute. Prog. Nat. Sci. Mater. Int. 23, 549-556 (2013).
22. Rigby K. M.& DeLeo, F. R. Neutrophils in innate host defense against Staphylococcus aureus infections. Semin. Immunopathol. 34, 237-259 (2012).
23. Bröker, B., Mrochen, D.& Péton, V. The T cell response to Staphylococcus aureus. Pathogens 5, 31 (2016).
24. Lüthje, F. L.et al.Receptor activator of nuclear factor kappa-B ligand is not regulated during chronic osteomyelitis in pigs. J. Comp. Pathol. 179, 7-24 (2020).
25. Libraty, D. H., Patkar, C.& Torres, B. Staphylococcus aureus reactivation osteomyelitis after 75 years. N. Engl. J. Med. 366, 481-482 (2012).
26. Fraunholz M.& Sinha, B. Intracellular Staphylococcus aureus: live-in and let die. Front. Cell. Infect. Microbiol. 2, 43(2012).
27. Garzoni C.& Kelley, W. L. Return of the Trojan horse: intracellular phenotype switching and immune evasion by Staphylococcus aureus. EMBO Mol. Med. 3, 115-117 (2011).
28. Edwards A. M., Potts J. R., Josefsson E.& Massey, R. C. Staphylococcus aureus host cell invasion and virulence in sepsis is facilitated by the multiple repeats within FnBPA. PLoS Pathog. 6, e1000964(2010).
29. Ellington, J. K.et al. Intracellular Staphylococcus aureus: a mechanism for the indolence of osteomyelitis. J. Bone Joint Surg. Br. 85-B, 918-921 (2003).
30. Josse, J., Velard, F.& Gangloff, S. C. Staphylococcus aureus vs. osteoblast: relationship and consequences in osteomyelitis. Front. Cell. Infect. Microbiol. 5, 85(2015).
31. Münzenmayer, L.et al.Influence of sae-regulated and agr-regulated factors on the escape of Staphylococcus aureus from human macrophages: S. aureus factors for macrophage escape. Cell. Microbiol. 18, 1172-1183 (2016).
32. Proctor, R. A.et al.Small colony variants: a pathogenic form of bacteria that facilitates persistent and recurrent infections. Nat. Rev. Microbiol. 4, 295-305 (2006).
33. Cai, Y.et al.The role of Staphylococcus aureus small colony variants in intraosseous invasion and colonization in periprosthetic joint infection. Bone Jt. Res. 11, 843-853 (2022).
34. You L. D., Weinbaum S., Cowin S. C.& Schaffler, M. B. Ultrastructure of the osteocyte process and its pericellular matrix. Anat. Rec. A. Discov. Mol. Cell. Evol. Biol. 278A, 505-513 (2004).
35. Gatica, D., Lahiri, V.& Klionsky, D. J. Cargo recognition and degradation by selective autophagy. Nat. Cell Biol. 20, 233-242 (2018).
36. Zoller, S. D.et al.Evading the host response: Staphylococcus “hiding” in cortical bone canalicular system causes increased bacterial burden. Bone Res. 8, 43(2020).
37. Masters, E. A.et al.Staphylococcus aureus cell wall biosynthesis modulates bone invasion and osteomyelitis pathogenesis. Front. Microbiol. 12, 723498(2021).
38. de Mesy Bentley, K. L., MacDonald, A., Schwarz, E. M. & Oh, I. Chronic osteomyelitis with Staphylococcus aureus deformation in submicron canaliculi of osteocytes: a case report. J. Bone Joint Surg. Am. 8, e8(2018).
39. Teng, H.et al.Novel Insights into the evolution of the caveolin superfamily and mechanisms of antiapoptotic effects and cell proliferation in lamprey. Dev. Comp. Immunol. 95, 118-128 (2019).
40. Karygianni L., Ren Z., Koo H.& Thurnheer, T. Biofilm matrixome: extracellular components in structured microbial communities. Trends Microbiol. 28, 668-681 (2020).
41. Kremers, H. M.et al.Trends in the epidemiology of osteomyelitis: a populationbased study, 1969 to 2009. J. Bone Jt. Surg. 97, 837-845 (2015).
42. Zimmerli, W., Trampuz, A.& Ochsner, P. E. Prosthetic-joint infections. N. Engl. J. Med. 351, 1645-1654 (2004).
43. Yousif, A., Jamal, M. A.& Raad, I. Biofilm-based central line-associated bloodstream infections. Adv. Exp. Med. Biol. 830, 157-179 (2015).
44. Mottola, C.et al.Susceptibility patterns of Staphylococcus aureus biofilms in diabetic foot infections. BMC Microbiol. 16, 119(2016).
45. Guo, H.et al.Biofilm and small colony variants— an update on Staphylococcus aureus strategies toward drug resistance. Int. J. Mol. Sci. 23, 1241(2022).
46. Jamal, M.et al.Bacterial biofilm and associated infections. J. Chin. Med. Assoc. 81, 7-11 (2018).
47. Moormeier D. E.& Bayles, K. W. Staphylococcus aureus biofilm: a complex developmental organism. Mol. Microbiol. 104, 365-376 (2017).
48. Schilcher, K. & Horswill, A. R. Staphylococcal biofilm development: structure, regulation,treatment strategies. Microbiol. Mol. Biol. Rev. MMBR 84, e00026-19 (2020).
49. O’Neill, E.et al. A novel Staphylococcus aureus biofilm phenotype mediated by the fibronectin-binding proteins, FnBPA and FnBPB. J. Bacteriol. 190, 3835-3850 (2008).
50. Beaussart, A., Feuillie, C. & El-Kirat-Chatel, S. The microbial adhesive arsenal deciphered by atomic force microscopy. Nanoscale 12, 23885-23896 (2020).
51. Mangwani, N., Kumari, S.& Das, S. Bacterial biofilms and quorum sensing: fidelity in bioremediation technology. Biotechnol. Genet. Eng. Rev. 32, 43-73 (2016).
52. Boles B. R.& Horswill, A. R. Staphylococcal biofilm disassembly. Trends Microbiol. 19, 449-455 (2011).
53. Lister J. L.& Horswill, A. R. Staphylococcus aureus biofilms: recent developments in biofilm dispersal. Front. Cell. Infect. Microbiol. 4, 178(2014).
54. Carek, P. J., Dickerson, L. M. & Sack, J. L. Diagnosis and management of osteomyelitis. Am. Fam. Physician 63, 2413-2420 (2001).
55. Cheng, A. G.et al.Contribution of coagulases towards Staphylococcus aureus disease and protective immunity. PLoS Pathog 6, e1001036 (2010).
56. Hofstee, M. I.et al.Three-dimensional in vitro Staphylococcus aureus abscess communities display antibiotic tolerance and protection from neutrophil clearance. Infect. Immun. 88, e00293-20 (2020).
57. Fey P. D.Modality of bacterial growth presents unique targets: how do we treat biofilm-mediated infections? Curr. Opin. Microbiol. 13, 610-615 (2010).
58. Kavanagh, N.et al.Staphylococcal osteomyelitis: disease progression, treatment challenges, and future directions. Clin. Microbiol. Rev. 31, e00084-17 (2018).
59. Otto M.Staphylococcus epidermidis — the ‘accidental’ pathogen. Nat. Rev. Microbiol. 7, 555-567 (2009).
60. Konto-Ghiorghi, Y. et al. Dual role for pilus in adherence to epithelial cells and biofilm formation in streptococcus agalactiae. PLoS Pathog. 5, e1000422(2009).
61. Willett J. L.E. et al. Comparative biofilm assays using enterococcus faecalis OG1RF identify new determinants of biofilm formation. mBio. 12, e01011-e01021 (2021).
62. Dale J. L., Cagnazzo J., Phan C. Q., Barnes A. M.T. & Dunny, G. M. Multiple roles for enterococcus faecalis glycosyltransferases in biofilm-associated antibiotic resistance, cell envelope integrity, and conjugative transfer. Antimicrob. Agents Chemother. 59, 4094-4105 (2015).
63. Dale J. L., Nilson J. L., Barnes A. M.T. & Dunny, G. M. Restructuring of enterococcus faecalis biofilm architecture in response to antibiotic-induced stress. Npj Biofilms Microbiomes 3, 15 (2017).
64. Pang Z.Antibiotic resistance in Pseudomonas aeruginosa_ mechanisms and alternative therapeutic strategies. Biotechnol. Adv. 37, 177-192 (2019).
65. Chirgwin K.& Gleich, S. Listeria monocytogenes osteomyelitis. Arch. Intern. Med. 149, 931-932 (1989).
66. Bariteau, J. T.et al.Fungal osteomyelitis and septic arthritis. J. Am. Acad. Orthop. Surg. 22, 390-401 (2014).
67. Vazquez M.Osteomyelitis in children. Curr. Opin. Pediatr. 14, 112-115 (2002).
68. Epps H.Osteomyelitis in patients who have sickle-cell disease. Diagnosis and management. J. Bone Joint. Surg. Am. 73, 1281-1294 (1991).
69. Ho-Shui-Ling, A.et al. Bone regeneration strategies: engineered scaffolds, bioactive molecules and stem cells current stage and future perspectives. Biomaterials 180, 143-162 (2018).
70. Chen, Y.et al.Effects of Pereskia aculeate miller petroleum ether extract on complete Freund’s adjuvant-induced rheumatoid arthritis in rats and its potential molecular mechanisms. Front. Pharmacol. 13, 869810(2022).
71. Nightingale, T. D.et al.Tuning the endothelial response: differential release of exocytic cargos from Weibel‐Palade bodies. J. Thromb. Haemost. 16, 1873-1886 (2018).
72. Zhou, J.et al.BLT1 in dendritic cells promotes Th1/Th17 differentiation and its deficiency ameliorates TNBS-induced colitis. Cell. Mol. Immunol. 15, 1047-1056 (2018).
73. Mussbacher M., Derler M., Basílio J.& Schmid, J. A. NF-κB in monocytes and macrophages - an inflammatory master regulator in multitalented immune cells. Front. Immunol. 14, 1134661(2023).
74. Vignais, P. V. The superoxide-generating NADPH oxidase: structural aspects and activation mechanism. Cell. Mol. Life Sci. CMLS 59, 1428-1459 (2002).
75. Newman, H., Shih, Y. V.& Varghese, S. Resolution of inflammation in bone regeneration: from understandings to therapeutic applications. Biomaterials 277, 121114 (2021).
76. Alder, K. D.et al.Intracellular Staphylococcus aureus in bone and joint infections: a mechanism of disease recurrence, inflammation, and bone and cartilage destruction. Bone 141, 115568 (2020).
77. Krauss, J. L.et al. Staphylococcus aureus infects osteoclasts and replicates intracellularly. mBio 10, e02447-19 (2019).
78. Wong R. M.Y. et al. A systematic review on current osteosynthesis-associated infection animal fracture models. J. Orthop. Transl. 23, 8-20 (2020).
79. Laubach, M.et al.Clinical translation of a patient-specific scaffold-guided bone regeneration concept in four cases with large long bone defects. J. Orthop. Transl. 34, 73-84 (2022).
80. McNeill, E. P.et al. Characterization of a pluripotent stem cell-derived matrix with powerful osteoregenerative capabilities. Nat. Commun. 11, 3025(2020).
81. Mitra D., Whitehead J., Yasui, O. W. & Leach, J. K. Bioreactor culture duration of engineered constructs influences bone formation by mesenchymal stem cells. Biomaterials 146, 29-39 (2017).
82. Nandi, S. K.et al.Understanding osteomyelitis and its treatment through local drug delivery system. Biotechnol. Adv. 34, 1305-1317 (2016).
83. Karki, K., Sigdel, S.& Kafle, S. Is it worth adding systemic antibiotics to inhalational tobramycin therapy to treat pseudomonas infections in cystic fibrosis? Cureus 13, e17326 (2021).
84. Wen Q., Gu F., Sui Z., Su Z.& Yu, T. The process of osteoblastic infection by Staphylococcus aureus. Int. J. Med. Sci. 17, 1327-1332 (2020).
85. Zimmerli, W. & Sendi, P. Orthopaedic biofilm infections. APMIS 125, 353-364 (2017).
86. Govaert, G. A. M.et al. Diagnosing fracture-related infection: current concepts and recommendations. J. Orthop. Trauma 34, 8-17 (2020).
87. Zhang, D.et al.Efficacy of novel nano-hydroxyapatite/polyurethane composite scaffolds with silver phosphate particles in chronic osteomyelitis. J. Mater. Sci. Mater. Med. 30, 59(2019).
88. Murphy, C. M., Haugh, M. G. & O’Brien, F. J. The effect of mean pore size on cell attachment, proliferation and migration in collagen-glycosaminoglycan scaffolds for bone tissue engineering. Biomaterials 31, 461-466 (2010).
89. Masters, E. A.et al.Skeletal infections: microbial pathogenesis, immunity and clinical management. Nat. Rev. Microbiol. 20, 385-400 (2022).
90. Parsons B.& Strauss, E. Surgical management of chronic osteomyelitis. Am. J. Surg. 188, 57-66 (2004).
91. Saavedra-Lozano,J. et al. Bone and joint infections. Pediatr. Infect. Dis. J. 36, 788-799 (2017).
92. Urish K. L.& Cassat, J. E. Staphylococcus aureus osteomyelitis: bone, bugs, and surgery. Infect. Immun. 88, e00932-19 (2020).
93. Lehar, S. M.et al. Novel antibody-antibiotic conjugate eliminates intracellular S. aureus. Nature 527, 323-328 (2015).
94. Wassif R. K., Elkayal M., Shamma R. N.& Elkheshen, S. A. Recent advances in the local antibiotics delivery systems for management of osteomyelitis. Drug Deliv. 28, 2392-2414 (2021).
95. Liu, Y., Li, X.& Liang, A. Current research progress of local drug delivery systems based on biodegradable polymers in treating chronic osteomyelitis. Front. Bioeng. Biotechnol. 10, 1042128(2022).
96. Inzana J. A., Schwarz E. M., Kates, S. L. & Awad, H. A. Biomaterials approaches to treating implant-associated osteomyelitis. Biomaterials 81, 58-71 (2016).
97. Li, J.et al.Transformation of arginine into zero-dimensional nanomaterial endows the material with antibacterial and osteoinductive activity. Sci. Adv. 9, eadf8645 (2023).
98. Ghosh, S.et al.A potent antibiotic-loaded bone-cement implant against staphylococcal bone infections. Nature Biomed. Eng. 6, 1180-1195 (2022).
99. Wang W.& Yeung, K. W. Bone grafts and biomaterials substitutes for bone defect repair: a review. Bioact. Mater. 2, 224-247 (2017).
100. Zhang, M.et al.3D printing of Haversian bone-mimicking scaffolds for multicellular delivery in bone regeneration. Sci. Adv. 6, eaaz6725 (2020).
101. Li, Y.et al.A review on functionally graded materials and structures via additive manufacturing: from multi‐scale design to versatile functional properties. Adv. Mater. Technol. 5, 1900981(2020).
102. Sun J.& Tan, H. Alginate-based biomaterials for regenerative medicine applications. Materials (Basel) 6, 1285-1309 (2013).
103. Lu, G.et al.An instantly fixable and self-adaptive scaffold for skull regeneration by autologous stem cell recruitment and angiogenesis. Nat. Commun. 13, 2499(2022).
104. Yuan, B.et al.A biomimetically hierarchical polyetherketoneketone scaffold for osteoporotic bone repair. Sci. Adv. 6, eabc4704 (2020).
105. Ren, Y.et al.Photoresponsive materials for antibacterial applications. Cell Rep. Phys. Sci. 1, 100245(2020).
106. Yang, K.et al.Bio-functional design, application and trends in metallic biomaterials. Int. J. Mol. Sci. 19, 24(2017).
107. Goriainov V., Cook R., Latham J. M., Dunlop D. G.& Oreffo, R. O. C. Bone and metal: an orthopaedic perspective on osseointegration of metals. Acta Biomater. 10, 4043-4057 (2014).
108. Sukhanova, A.et al.Dependence of nanoparticle toxicity on their physical and chemical properties. Nanoscale Res. Lett. 13, 44(2018).
109. Shaikh, S.et al.Mechanistic insights into the antimicrobial actions of metallic nanoparticles and their implications for multidrug resistance. Int. J. Mol. Sci. 20, 2468(2019).
110. Lemire, J. A. & Turner, R. J. Mechanisms underlying the antimicrobial capacity of metals. in Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria (ed. De Bruijn, F. J.) 215-224 (Wiley, 2016). https://doi.org/10.1002/ 9781119004813.ch18.
111. Warnes S. L.& Keevil, C. W. Lack of involvement of Fenton chemistry in death of methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus and destruction of their genomes on wet or dry copper alloy surfaces. Appl. Environ. Microbiol. 82, 2132-2136 (2016).
112. Spirescu V. A., Chircov C., Grumezescu A. M., Vasile B.& Inorganic nanoparticles and composite films for antimicrobial therapies. Int. J. Mol. Sci. 22, 4595(2021).
113. Vallet‐Regí, M. & Ruiz‐Hernández, E. Bioceramics: from bone regeneration to cancer nanomedicine. Adv. Mater. 23, 5177-5218 (2011).
114. Shuai, C.et al.Structure and properties of nano-hydroxypatite scaffolds for bone tissue engineering with a selective laser sintering system. Nanotechnology 22, 285703 (2011).
115. Zhao C., Liu W., Zhu M., Wu C.& Zhu, Y. Bioceramic-based scaffolds with antibacterial function for bone tissue engineering: a review. Bioact. Mater. 18, 383-398 (2022).
116. Li, S.et al.Antibacterial hydrogels. Adv. Sci. 5, 1700527(2018).
117. Oda Y., Kanaoka S., Sato T., Aoshima, S. & Kuroda, K. Block versus random amphiphilic copolymers as antibacterial agents. Biomacromolecules 12,3581-3591 (2011).
118. Zhou, H.et al. Stimuli-responsive peptide hydrogels for biomedical applications. J. Mater. Chem. B 12, 1748-1774 (2024).
119. Liu, C.et al.Research progress of polyphenols in nanoformulations for antibacterial application. Mater. Today Bio. 21, 100729(2023).
120. Hickok N. J.& Shapiro, I. M. Immobilized antibiotics to prevent orthopaedic implant infections. Adv. Drug Deliv. Rev. 64, 1165-1176 (2012).
121. Zegre, M.et al.Poly(DL-lactic acid) scaffolds as a bone targeting platform for the co-delivery of antimicrobial agents against S. aureus-C.albicans mixed biofilms. Int. J. Pharm. 622, 121832(2022).
122. Filippi M., Born G., Chaaban M.& Scherberich, A. Natural polymeric scaffolds in bone regeneration. Front. Bioeng. Biotechnol. 8, 474(2020).
123. Tamay, D. G.et al.3D and 4D printing of polymers for tissue engineering applications. Front. Bioeng. Biotechnol. 7, 164(2019).
124. Xue, X.et al.Fabrication of physical and chemical crosslinked hydrogels for bone tissue engineering. Bioact. Mater. 12, 327-339 (2022).
125. Arkenberg, M. R., Nguyen, H. D. & Lin, C. C. Recent advances in bio-orthogonal and dynamic crosslinking of biomimetic hydrogels. J. Mater. Chem. B 8, 7835-7855 (2020).
126. Schmidleithner, C.et al.Application of high resolution DLP stereolithography for fabrication of tricalcium phosphate scaffolds for bone regeneration. Biomed. Mater. 14, 045018(2019).
127. Zeng, H.et al.Indirect selective laser sintering-printed microporous biphasic calcium phosphate scaffold promotes endogenous bone regeneration via activation of ERK1/2 signaling. Biofabrication 12, 025032 (2020).
128. Mohd Pu’ad,N. A. S. et al. Review on the fabrication of fused deposition modelling (FDM) composite filament for biomedical applications. Mater. Today Proc. 29, 228-232 (2020).
129. Koons, G. L., Diba, M.& Mikos, A. G. Materials design for bone-tissue engineering. Nat. Rev. Mater. 5, 584-603 (2020).
130. Turnbull, G.et al.3D bioactive composite scaffolds for bone tissue engineering. Bioact. Mater. 3, 278-314 (2018).
131. Amini, A. R., Laurencin, C. T.& Nukavarapu, S. P. Bone tissue engineering: recent advances and challenges. Crit. Rev. Biomed. Eng. 40, 363-408 (2012).
132. Haleem A., Javaid M., Khan, R. H. & Suman, R. 3D printing applications in bone tissue engineering. J. Clin. Orthop. Trauma 11, S118-S124 (2020).
133. He, M.et al.Layer-by-layer assembled black phosphorus/chitosan composite coating for multi-functional PEEK bone scaffold. Compos. Part B Eng. 246, 110266(2022).
134. Sun, Z.et al.A dexamethasone-eluting porous scaffold for bone regeneration fabricated by selective laser sintering. ACS Appl. Bio. Mater. 3, 8739-8747 (2020).
135. Song, P.et al.DLP fabricating of precision GelMA/HAp porous composite scaffold for bone tissue engineering application. Compos. Part B Eng. 244, 110163(2022).
136. Yang, L.et al.Coaxial bioelectrospinning of P34HB/PVA microfibers biomimetic scaffolds with simultaneity cell-laden for improving bone regeneration. Mater. Des. 213, 110349(2022).
137. De Moraes, R. et al. Viability of collagen matrix grafts associated with nanohydroxyapatite and elastin in bone repair in the experimental condition of ovariectomy. Int. J. Mol. Sci. 24, 15727(2023).
138. Manavitehrani, I.et al. Formation of porous biodegradable scaffolds based on poly(propylene carbonate) using gas foaming technology. Mater. Sci. Eng. C 96, 824-830 (2019).
139. Radhakrishnan J., Muthuraj M., Gandham G. S.P. D., Sethuraman, S. & Subramanian, A. Nanohydroxyapatite-protein interface in composite sintered scaffold influences bone regeneration in rabbit ulnar segmental defect. J. Mater. Sci. Mater. Med. 33, 36(2022).
140. Baek J. W., Kim K. S., Park H.& Kim, B. S. Marine plankton exoskeletone-derived hydroxyapatite/polycaprolactone composite 3D scaffold for bone tissue engineering. Biomater. Sci. 10, 7055-7066 (2022).
141. Wassif, R. K.et al.Injectable systems of chitosan in situ forming composite gel incorporating linezolid-loaded biodegradable nanoparticles for long-term treatment of bone infections. Drug Deliv. Transl. Res. 14, 80-102 (2024).
142. Qiu, X.et al.Experimental study of β-TCP scaffold loaded with VAN/PLGA microspheres in the treatment of infectious bone defects. Colloids Surf. B Biointerfaces 213, 112424 (2022).
143. Shen, M.et al.3D bioprinting of in situ vascularized tissue engineered bone for repairing large segmental bone defects. Mater. Today Bio. 16, 100382(2022).
144. Wang, Y.et al.A recombinant parathyroid hormone‐related peptide locally applied in osteoporotic bone defect. Adv. Sci. 10, 2300516(2023).
145. Yang, C.et al.3D printed enzyme‐functionalized scaffold facilitates diabetic bone regeneration. Adv. Funct. Mater. 31, 2101372(2021).
146. Wang, C.et al.Advanced reconfigurable scaffolds fabricated by 4D printing for treating critical-size bone defects of irregular shapes. Biofabrication 12, 045025 (2020).
147. Deng, Y.et al.4D printed shape memory polyurethane-based composite for bionic cartilage scaffolds. ACS Appl. Polym. Mater. 5, 1283-1292 (2023).
148. White, J., Foley, M.& Rowley, A. A novel approach to 3D-printed fabrics and garments. 3D Print. Addit. Manuf. 2, 145-149 (2015).
149. Capuana E., Lopresti F., Carfì Pavia, F., Brucato, V. & La Carrubba, V. Solutionbased processing for scaffold fabrication in tissue engineering applications: a brief review. Polymers 13, 2041 (2021).
150. Christy, P. N.et al.Biopolymeric nanocomposite scaffolds for bone tissue engineering applications - a review. J. Drug Deliv. Sci. Technol. 55, 101452(2020).
151. Shin, M., Yoshimoto, H.& Vacanti, J. P. In vivo bone tissue engineering using mesenchymal stem cells on a novel electrospun nanofibrous scaffold. Tissue Eng. 10, 33-41 (2004).
152. Costantini, M. & Barbetta, A. Gas foaming technologies for 3D scaffold engineering. Funct. 3D Tissue Eng. Scaffolds 127-149 https://doi.org/10.1016/B978-0- 08-100979-6.00006-9 (2018).
153. Salerno A., Oliviero M., Di Maio, E., Iannace, S. & Netti, P. A. Design of porous polymeric scaffolds by gas foaming of heterogeneous blends. J. Mater. Sci. Mater. Med. 20, 2043-2051 (2009).
154. Fereshteh Z.Freeze-drying technologies for 3D scaffold engineering. Funct. 3D Tissue Eng. Scaffolds 151-174 https://doi.org/10.1016/B978-0-08-100979- 6.00007-0 (2018).
155. Puppi D., Chiellini F., Piras A. M.& Chiellini, E. Polymeric materials for bone and cartilage repair. Prog. Polym. Sci. 35, 403-440 (2010).
156. Grenier, J.et al.Interplay between crosslinking and ice nucleation controls the porous structure of freeze-dried hydrogel scaffolds. Biomater. Adv. 139, 212973(2022).
157. Prasad, A., Sankar, M. R.& Katiyar, V. State of art on solvent casting particulate leaching method for orthopedic scaffoldsfabrication. Mater. Today Proc. 4, 898-907 (2017).
158. Liao, C.et al.Fabrication of porous biodegradable polymer scaffolds using a solvent merging/particulate leaching method. J. Biomed. Mater. Res. 59, 676-681 (2002).
159. Winarso R., Anggoro P. W., Ismail R., Jamari J.& Bayuseno, A. P. Application of fused deposition modeling (FDM) on bone scaffold manufacturing process: a review. Heliyon 8, e11701 (2022).
160. Bittner, S. M.et al.Fabrication and mechanical characterization of 3D printed vertical uniform and gradient scaffolds for bone and osteochondral tissue engineering. Acta Biomater. 90, 37-48 (2019).
161. Mazzoli A.Selective laser sintering in biomedical engineering. Med. Biol. Eng. Comput. 51, 245-256 (2013).
162. Liu F.H., Lee R.T., Lin, W.H. & Liao, Y.S. Selective laser sintering of bio-metal scaffold. Procedia. CIRP 5, 83-87 (2013).
163. Zhang L., Yang G., Johnson B. N.& Jia, X. Three-dimensional (3D) printed scaffold and material selection for bone repair. Acta Biomater. 84, 16-33 (2019).
164. Melchels, F. P. W., Feijen, J. & Grijpma, D. W. A review on stereolithography and its applications in biomedical engineering. Biomaterials 31, 6121-6130 (2010).
165. Chen, Q.et al.A study on biosafety of HAP ceramic prepared by SLA-3D printing technology directly. J. Mech. Behav. Biomed. Mater. 98, 327-335 (2019).
166. Ligon S. C., Liska R., Stampfl J., Gurr M.& Mülhaupt, R. Polymers for 3D printing and customized additive manufacturing. Chem. Rev. 117, 10212-10290 (2017).
167. Ong, C. S.et al.3D bioprinting using stem cells. Pediatr. Res. 83, 223-231 (2018).
168. Chimene, D.et al. Nanoengineered ionic-covalent entanglement (NICE) bioinks for 3D bioprinting. ACS Appl. Mater. Interfaces 10, 9957-9968 (2018).
169. Choe G., Oh S., Seok J. M., Park, S. A. & Lee, J. Y. Graphene oxide/alginate composites as novel bioinks for three-dimensional mesenchymal stem cell printing and bone regeneration applications. Nanoscale 11, 23275-23285 (2019).
170. Zhang, X.et al.3D printed PCLA scaffold with nano‐hydroxyapatite coating doped green tea EGCG promotes bone growth and inhibits multidrug‐resistant bacteria colonization. Cell Prolif 55, e13289 (2022).
171. Hu, X.et al.Fabrication of 3D gel-printed β-tricalcium phosphate/titanium dioxide porous scaffolds for cancellous bone tissue engineering. Int. J. Bioprinting 9, 673 (2023).
172. Chang, R., Nam, J. & Sun, W. Effects of dispensing pressure and nozzle diameter on cell survival from solid freeform fabrication-based direct cell writing. Tissue Eng. Part A 14, 41-48 (2008).
173. Wang, X.et al.3D bioprinting technologies for hard tissue and organ engineering. Materials 9, 802 (2016).
174. Dey M.& Ozbolat, I. T. 3D bioprinting of cells, tissues and organs. Sci. Rep. 10, 14023(2020).
175. Chaudhuri O., Cooper-White J., Janmey P. A., Mooney, D. J. & Shenoy, V. B. Effects of extracellular matrix viscoelasticity on cellular behaviour. Nature 584, 535-546 (2020).
176. Falahati, M.et al. Smart polymers and nanocomposites for 3D and 4D printing. Mater. Today 40, 215-245 (2020).
177. Pinho, A. C., Buga, C. S.& Piedade, A. P. The chemistry behind 4D printing. Appl. Mater. Today 19, 100611 (2020).
178. Hager M. D., Bode S., Weber, C. & Schubert, U. S. Shape memory polymers: past, present and future developments. Prog. Polym. Sci. 49-50, 3-33 (2015).
179. Kempaiah, R. & Nie, Z. From nature to synthetic systems: shape transformation in soft materials. J. Mater Chem. B 2, 2357-2368 (2014).
180. Hu, X.et al.Novel 3D printed shape-memory PLLA-TMC/GA-TMC scaffolds for bone tissue engineering with the improved mechanical properties and degradability. Chin. Chem. Lett. 34, 107451(2023).
181. Sadowska J. M., Genoud K. J., Kelly, D. J. & O’Brien, F. J. Bone biomaterials for overcoming antimicrobial resistance: advances in non-antibiotic antimicrobial approaches for regeneration of infected osseous tissue. Mater. Today 46, 136-154 (2021).
182. Zheng, Y.et al.Neuro-regenerative imidazole-functionalized GelMA hydrogel loaded with hAMSC and SDF-1α promote stem cell differentiation and repair focal brain injury. Bioact. Mater. 6, 627-637 (2021).
183. Cheng, Q.et al. Dual cross-linked hydrogels with injectable, self-healing,antibacterial properties based on the chemical and physical cross-linking. Biomacromolecules 22, 1685-1694 (2021).
184. Beninatto, R.et al. Photocrosslinked hydrogels from coumarin derivatives of hyaluronic acid for tissue engineering applications. Mater. Sci. Eng. C 96, 625-634 (2019).
185. Rosenquist, J.et al. An injectable, shape-retaining collagen hydrogel crosslinked using thiol-maleimide click chemist

Funding

Ning Hu([e-mail]) or Xulin Hu([e-mail])