Speaker
Description
Introduction
The auditory system is essential for speech development, spatial orientation, and communication; dysfunction leads to hearing loss, affecting over 466 million individuals globally, making it one of the top five leading causes of the most years lived with disability [1]. Conductive hearing loss frequently arises from tympanic membrane perforation or ossicular chain disruption, commonly managed by ossiculoplasty [2]. Conventional autografts and alloplastic prostheses demonstrate limitations regarding biocompatibility, stability, cost, and long-term efficacy [3, 4]. Advances in three-dimensional printing have enabled patient-specific ossicular prostheses, while emerging bioprinting technologies offer the possibility of fabricating living, functional implants [5, 6]. The present study aims to generate a human stapes via 3D bioprinting, potentially providing a physiological and durable solution for auditory rehabilitation.
Materials and Methods
Human stapes were harvested from cadavers via a transcanal endoscopic approach, fixed in 1% PFA, and imaged with a SkyScan 1176 micro-CT. Stapes-shaped molds (ZA 35 MOULD) were produced for bioprinting. MG63 osteosarcoma cells (1×10⁶) were suspended in Cellink Bone bioink, cast into molds, crosslinked with CaCl₂, and cultured for 3 weeks in osteogenic MEMα medium; cDMEM served as control. Osteogenic differentiation was assessed by PCR for FN1, BGLAP, BMP2, COL1A1, and SP7. Mineralization was evaluated by Alizarin Red staining with spectrophotometric quantification at 405 nm.
Results
Stapes was shaped in a mould using biogel mixed with M63 (Figure 1). qRT-PCR demonstrated upregulation of osteogenic markers in MG63 cells cultured in osteogenic MEMα compared with cDMEM controls. Expression of FN1, BGLAP, BMP2, COL1A1, and SP7 were elevated after 3 weeks of culture. Among these, BGLAP and COL1A1 showed the highest relative expression, while SP7 only moderately increased. cDMEM control cultures barely expressed the above genes. The results confirm successful osteogenic differentiation within the stapes constructs.
Calcium-containing osteocytes, shown by Alizarin red stain, were only detected in the 3D bioprinted models, incubated in α-MEM, indicating intense mineralization.
Discussion
Bioprinted stapes constructs with MG63 cells in bioink showed osteogenic differentiation, evidenced by upregulated markers and calcium deposition. Future work should explore primary cells, mechanical testing, and, in vivo evaluation for auditory ossicle replacement.
References
1. WHO, O.O. 2021;
2. Campbell, E. and N.C. Tan, Ossicular-Chain Dislocation, in StatPearls. 2025: Treasure Island (FL).
3. Young, A. and M. Ng, Ossiculoplasty, in StatPearls. 2025: Treasure Island (FL).
4. Sharma, M.O., et al., Hearing Outcome in Ossiculoplasty With Autologous Incus and Teflon Prosthesis in Chronic Otitis Media: a Comparative Study. Indian J Otolaryngol Head Neck Surg, 2022. 74(Suppl 1): p. 345-350.
5. Heikkinen, A.K., et al., Feasibility of 3D-printed middle ear prostheses in partial ossicular chain reconstruction. Int J Bioprint, 2023. 9(4): p. 727.
6. Hirsch, J.D., R.L. Vincent, and D.J. Eisenman, Surgical reconstruction of the ossicular chain with custom 3D printed ossicular prosthesis. 3D Print Med, 2017. 3(1): p. 7.
Acknowledgements
This research was supported by the Eurostars BioDegBone project.