Page 431 - v11i4

International Journal of Bioprinting Swelling–shrinking behavior of hydrogel

ambient RH conditions for hydrogel extrusion. Printing Acknowledgments
trials were conducted to validate the effectiveness of the
proposed approach in mitigating geometric shrinkage None.
in 3D-printed architectures. The main conclusions are
summarized as follows: Funding
(i) A FEM thermal–humidity–multiphase flow The authors deeply acknowledge the financial support
coupling field simulation model was proposed and from the Key Research and Development Plan Project
experimentally validated, successfully predicting the of Heilongjiang Province (grant no. 2022ZX02C22);
geometric variation of hydrogel filaments under a the Science and Technology Innovation Talent
variety of ambient RH conditions. Project on Manufacturing Industry of Harbin (grant
no. 2023HBRCGD011, 2022CXRCGD029); the
(ii) The optimal RH conditions for 3D printing of Interdisciplinary Research Foundation of HIT (grant
hydrogel filaments with diameters of 0.2, 0.3, and 0.4 no. IR2021223); and the Natural Science Foundation of
mm were identified as 90, 80, and 60%, respectively.
Chongqing (grant no. CSTB2023NSCQ-MSX0822).
(iii) Printing trials using F-127 hydrogel materials
demonstrated that higher ambient RH effectively Conflict of interest
prevents both uncontrollable geometric swelling and
shrinkage during the 3D printing process. Dr. Swee Leong Sing serves as the Editorial Board Member
of the journal, but did not in any way involve in the
(iv) Under optimized RH conditions for hydrogel editorial and peer-review process conducted for this paper,
filaments, 3D architectures of the human ear were directly or indirectly. Other authors declare they have no
successfully manufactured with an effective size of competing interests.
20 mm (length) × 10 mm (width) × 10 mm (height).

It should be noted that the humidity-driven swelling– Author contributions
shrinking behavior discussed in this study is specific to Conceptualization: Qiang Gao
hydrogel-based biomaterials, such as F-127 and GelMA. Data curation: Qiang Gao
These materials possess high water content and strong Formal analysis: Lihua Lu
moisture responsiveness under ambient conditions. In Funding acquisition: Wei Zhang
contrast, thermoplastic biocompatible polymers, such Investigation: Peng Zhang
as polycaprolactone and polypropylene, are largely Methodology: Min Zhu
unaffected by humidity due to their hydrophobic nature
and low water uptake. Therefore, the findings of this study Project administration: Lihua Lu
are not intended to generalize across all biocompatible Resources: Le Xu
printing materials. Software: Kaicheng Yu
Supervision: Yifeng Yao
Although the present study provides a quantitative Validation: Swee Leong Sing
understanding of humidity-driven deformation in single- Visualization: Wei Zhang
layer hydrogel filaments, the current model is limited to Writing–original draft: Kaicheng Yu
2D cross-sectional simulations and does not fully capture Writing–review and editing: Kaicheng Yu
the 3D deposition dynamics of multilayer structures. In
practice, interlayer moisture transport, filament fusion Ethics approval and consent to participate
behavior, and cumulative deformation significantly impact
the final geometry and functionality of printed biomimetic Not applicable.
constructs. Due to the absence of robust theoretical models
for describing layer-by-layer coupling and time-dependent Consent for publication
structural evolution, accurate simulation of full 3D Not applicable.
architectures remains a challenge. Future work will focus
on developing a comprehensive, multi-physics 3D FEM Availability of data
framework that incorporates interlayer interactions and
global deformation mechanisms. This will further enhance The datasets generated and analyzed during the current
the predictive capability and practical value of the proposed study are available from the corresponding author upon
approach in large-scale hydrogel biomanufacturing. reasonable request.

Volume 11 Issue 4 (2025) 423 doi: 10.36922/IJB025220222