Proceedings of the
World Congress on Micro and Nano Manufacturing (WCMNM 2022 )
19–22 September 2022, Lueven, Belgium
doi:10.3850/978-981-18-5180-3_RP50-0050
Immersed Microfluidic Spinning of Calcium Alginate Microfibers Towards Tissue Engineering Applications
1Mechanical and Aerospace Engineering, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
2Materials and Manufacturing Technology, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
3Electrical Engineering and Computer Science, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
4Biomedical Engineering, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
ABSTRACT
Fabrication of micro- and nanofibers are critical for a wide range of applications from microelectronics to biotechnology. Alginate microfibers with diameter of tens to hundreds of microns play important role for tissue engineering and fibers of these diameters are impossible to fabricate via electrospinning and could only be produced via fluidic spinning. Typically, microfluidic spinning based on photopolymerization produces fibers that are not easily dissolvable, while fluidic spinning with chemical cross-linking employs complex setups of microfabricated chips or coaxial needles, aimed at precise control of the fiber diameter, but introducing the significant cost and complexity to the microfluidic setup. We demonstrate the immersed microfluidic spinning where a calcium alginate microfiber is produced via displacement of alginate solution through a single needle that is immersed in a cross-linking bath of calcium chloride solution. The resulting diameter of the fiber is characterized, and fiber diameter and topology of the deposited fiber is related to the concentration of the alginate solution (2, 4, and 6 wt%), needle gauge (30g, 25g, and 20g), the volumetric flow rate of the alginate solution (1 ml/min, 2 ml/min, and 2.7 ml/min). The resulting fiber diameter is smaller than the internal diameter of the needle and this dependence is explained by the continuity of the flow and increased rate of fall of the liquid jet upon its issuing from the needle. The fiber diameter (demonstrated diameter of fibers range from 100 microns to 1 mm) depends weakly on the volumetric flow rate and depends strongly on the needle diameter. It also seems that for smaller needle size greater concentration of alginate results in smaller diameter fibers and that this trend is not evident as needle diameter is increased. In terms of topology of the deposited fiber, the higher wt% alginate fiber produces larger loops, while smaller wt% alginate solution yields a denser topology of the overlaid fiber loops. We believe that the demonstrated simple setup of the immersed microfluidic spinning of the calcium alginate microfibers will be useful for creating tissue constructs, including the vascularized tissue implants.
Keywords: Immersed Microfluidic Spinning, Microfibers, Tissue Engineering, Biofabrication.
1Mechanical and Aerospace Engineering, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
2Materials and Manufacturing Technology, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
3Electrical Engineering and Computer Science, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
4Biomedical Engineering, University of California Irvine, 5200 Engineering Hall, Irvine, CA 92627, USA
ABSTRACT
Fabrication of micro- and nanofibers are critical for a wide range of applications from microelectronics to biotechnology. Alginate microfibers with diameter of tens to hundreds of microns play important role for tissue engineering and fibers of these diameters are impossible to fabricate via electrospinning and could only be produced via fluidic spinning. Typically, microfluidic spinning based on photopolymerization produces fibers that are not easily dissolvable, while fluidic spinning with chemical cross-linking employs complex setups of microfabricated chips or coaxial needles, aimed at precise control of the fiber diameter, but introducing the significant cost and complexity to the microfluidic setup. We demonstrate the immersed microfluidic spinning where a calcium alginate microfiber is produced via displacement of alginate solution through a single needle that is immersed in a cross-linking bath of calcium chloride solution. The resulting diameter of the fiber is characterized, and fiber diameter and topology of the deposited fiber is related to the concentration of the alginate solution (2, 4, and 6 wt%), needle gauge (30g, 25g, and 20g), the volumetric flow rate of the alginate solution (1 ml/min, 2 ml/min, and 2.7 ml/min). The resulting fiber diameter is smaller than the internal diameter of the needle and this dependence is explained by the continuity of the flow and increased rate of fall of the liquid jet upon its issuing from the needle. The fiber diameter (demonstrated diameter of fibers range from 100 microns to 1 mm) depends weakly on the volumetric flow rate and depends strongly on the needle diameter. It also seems that for smaller needle size greater concentration of alginate results in smaller diameter fibers and that this trend is not evident as needle diameter is increased. In terms of topology of the deposited fiber, the higher wt% alginate fiber produces larger loops, while smaller wt% alginate solution yields a denser topology of the overlaid fiber loops. We believe that the demonstrated simple setup of the immersed microfluidic spinning of the calcium alginate microfibers will be useful for creating tissue constructs, including the vascularized tissue implants.
Keywords: Immersed Microfluidic Spinning, Microfibers, Tissue Engineering, Biofabrication.
