Numerical study of the process parameters affecting the feature size of a microfiber fabricated by microfluidic-based bioprinting

Microfiber is a significant tubular structure due to its desirable properties, such as a large surface area and near-vessel shape. However, the fabrication of solid and hollow microfibers may face challenges with additive manufacturing (AM). 3D bioprinting is an AM technique with significant challenges, such as difficulty in high-precision printing of precise microfibers. Additionally, due to the unique advantages of microfluidic systems, such as flow control, laminar regime, and biocompatibility, these devices have great potential to integrate with 3D bioprinting. Therefore, enhancing AM methods with microfluidic technology is a prominent approach to fabricating heterogeneous microfibers. Several process parameters affect the geometry of microfibers produced by microfluidic-based printing platforms. Therefore, this study has focused on the numerical analysis of channel geometry, bioink properties, and process parameters on the microfibers’ feature size. In this regard, the results of the developed numerical model have been verified with experimental data. There is 85% agreement between the numerical model results and experimental data. These errors are attributed to the sheath fluid and sample fluid effects. Besides, a mathematical model was developed to predict the solid and hollow microfiber feature size. Altering the sample and sheath inlet velocity resulted in a range of solid microfiber diameters between 45 and 108 µm. The OD values have an error margin of up to 15%, while the ID error values have an error margin of up to 14%. The results of this study can be employed to optimize the channel geometry, bioink properties, and process parameters to achieve the desired functionally graded microfibers.