Introduction: Recently, many researchers have tried to develop a microfluidic device reconstructing in-vivo cell environment of human-organ so called organ-on-a-chip[1],[2]. However, the reconstitution of in-vivo nanotopography (e.g. extracellular matrix), which has been proven to influence on the function of human-organ, is a challenge for the development of organ-on-a-chip. Among various fabrication techniques for nanotopography, electrospinning is growing topic of interest due to its simple and versatile fabrication of nanofibers. However, conventional electrospinning process produced a nanofiber membrane adhered to a metal collector, and thus, additional steps such as mechanically or chemically peer-off and transfer[3] were required to integrate electrospun nanofiber membrane with organ-on-a-chip. To overcome such problem, electrolyte-assisted electrospinning has been introduced[4]. However, randomly oriented, free-standing nanofiber membrane was only reported by electrolyte-assisted electrospinning. Here, we present high-aligned, free-standing nanofiber membrane on a microfluidic device by electrolyte-assisted electrospinning. On a highly-aligned, free-standing nanofiber membrane, the alignment of brain endothelial cell line was achieved.
Materials and Methods: Poly(methyl methacrylate) (PMMA) plate with a thru-hole (2 mm width and 2 mm length) was prepared by laser cutting as shown in Figure 1(a). The 3M KCL electrolyte solution was utilized to collect nanofibers instead of a metal collector. The electrolyte solution was placed on the edges of the PMMA plate, and polycarprolactone (PCL) solution was ejected through the metal needles with applying 19 kV high voltage as shown in Figure 1(b). The electrolyte solution was removed from the PMMA plate, and electrospun nanofibers outside of the thru-hole was detached. Brain endothelial cell line (bEnd.3) was cultured on the highly aligned nanofiber membrane.
Results: Figure 2(a) shows high-aligned nanofibers on a PMMA plate. Through the highly aligned nanofibers, letters on the paper could be observed due to the semi-transparency of highly aligned nanofibers. Figure 2(b) shows the cross-sectional image of highly-aligned, free-standing nanofiber membrane integrated with the PMMA plate. The highly aligned nanofiber was achieved with electrolyte-assisted electrospinning as shown in Figure 2(c). Figure 3 shows a fluorescence microscopy image of aligned bEnd.3.
Discussion: An electrolyte solution enables as-spun nanofibers to be aligned on the PMMA plate without patterned metal collectors, which requires complicated preparation process. By tuning the electrospinning time, semi-transparent, and highly-aligned nanofiber membrane was achieved. The high-aligned nanofiber membrane could provide a nanotopography, which enables the alignment of endothelial cells.
Conclusion: We present a highly-aligned, free-standing nanofiber membrane on a microfluidic device by electrolyte-assisted electrospinning. The highly-aligned, free-standing nanofiber membrane provided in-vitro cell environment, enabling the alignment of brain endothelial cell line.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2011-0030075).; This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (No. 2014R1A2A1A01006527).
References:
[1] "Reconstituting organ-level lung functions on a chip," D. Huh, B.D. Matthews, A. Mammoto, M. Montoya-Zavala, H. Y. Hsin, and D. E. Ingber, Science, 328, 1662 (2010)
[2] “A multi-layer microfluidic device for efficient culture and analysis of renal tubular cells,” K.J. Jang, and K.Y. Suh, Lab on a Chip, 10, 36 (2010).
[3] “Electrospun nanofibers as a tool for architecture control in engineered cardiac tissue,” Y. Orlova, N. Magonme, L. Liu, Y. Chen, and K. Agladze, Biomaterials, 32, 5615 (2011).
[4] “Electrolyte-assisted electrospining for a self-assembled, free standing nanofiber membrane on a curved surface”, S.M.Park, and D.S.Kim, Advanced Materials, 27, 1682 (2015).