(C-86) Directional Alignment of Electrospun Nanofibers Using Resin 3D Printed Micro-slots

Introduction:: Nanofiber directionality is crucial in various applications, notably composite materials, and tissue engineering. This research employs a resin 3D-printed scaffold with parallel micro-slots to guide the collection of nanofibers. It's postulated that these micro-slots might modulate the surrounding electric field, thus serving as prime sites for nanofiber attraction. The core aim of this study is to elucidate the directional alignment of nanofibers over these 3D-printed resin micro-slots and evaluate this alignment across varying micro-slot widths.

Materials and Methods:: Three distinct scaffold designs were created and 3D printed using a stereolithography (SLA) resin printer (Formlabs, Form 3+) with a photopolymer resin (Formlabs, resin V4). Each scaffold incorporated seven parallel micro-slots. The first scaffold design had micro-slots with a width of 300 µm; the second, 400 µm; and the third, 600 µm. All scaffolds had dimensions of 8 mm x 10.4 mm and a height of 0.5 mm, with every micro-slot across the designs maintaining a uniform length of 3 mm. Five replicas of each scaffold design were fabricated for repeatability and accuracy in the study. The micro-slot sizes were precisely gauged using a Keyence digital microscope. Subsequently, the scaffolds were affixed to an aluminum foil collector sheet and secured by taping around their solid edges. The electrospinning apparatus was set at specific parameters to gather nanofibers using a 15% w/v PCL polymer solution. The nanofibers were examined under a scanning electron microscope for detailed observation and measurement.

Results, Conclusions, and Discussions::

Compared to the intended design specifications, the actual measurements of the micro-slots recorded widths of approximately 284, 351, and 536 µm. SEM observations elucidated distinct patterns in nanofiber alignment. The nanofibers were consistently aligned perpendicular to the centerline between every pair of adjacent micro-slots. Conversely, within the micro-slots, the nanofibers predominantly exhibited a parallel orientation. The nanofibers at the scaffold's solid periphery, particularly areas distant from the micro-slots, showed a more randomized alignment. This variability underscores the pronounced role of the micro-slots in steering nanofiber alignment. This suggests that the micro-slot structure of the scaffold likely modulated the adjacent electric field. This modulation created zones where electrostatic forces favor specific fiber alignments. Furthermore, the SEM images depicted a pristine nanofiber collection process devoid of fiber beading or splattering. 

The insights gained from this study underscore the importance of micro-slot structure in nanofiber alignment and hint at vast potential applications, ranging from enhancing tissue engineering strategies to optimizing composite material manufacturing, ultimately paving the way for innovations across various scientific domains.

 

Acknowledgements (Optional): : We would like to thank Fairfield University for the Undergraduate Summer Research Residency Program and providing the facilities to support this research.

References (Optional): :

[1]          “Three-Dimensional Printing and Electrospinning Dual-Scale Polycaprolactone Scaffolds with Low-Density and Oriented Fibers to Promote Cell Alignment,” Jul. 24, 2023. https://www.liebertpub.com/doi/epdf/10.1089/3dp.2019.0091 (accessed Jul. 24, 2023).

[2]          E. Malikmammadov, T. E. Tanir, A. Kiziltay, V. Hasirci, and N. Hasirci, “PCL and PCL-based materials in biomedical applications,” J. Biomater. Sci. Polym. Ed., vol. 29, no. 7–9, Art. no. 7–9, Jun. 2018, doi: 10.1080/09205063.2017.1394711.