279716 Modulating Electric Fields At Patterned Collectors for the Alignment of Sub-100nm Electrospun Nanofibers

Tuesday, October 30, 2012: 3:57 PM
Fayette (Westin )
Yi-Hsuan Su1, Vasudha Chaurey2, Frank Block3 and Nathan Swami1, (1)Electrical & Computer Engineering, University of Virginia, Charlottesville, VA, (2)Electrical & Computer Engineering Department, University of Virginia, Charlottesville, VA, (3)University of Virginia, Charlottesville, VA

Aligned nanofiber scaffolds are commonly applied within a variety of applications that require highly directional cues, such as tissue engineering, chemical sensing and ferroelectrics. In many cases, scaffolds composed of nanofibers with successively smaller sizes are required. Nanofiber alignment is usually enabled by rotating mandrel-based mechanical approaches [1] or by electrical approaches for alignment based on field modification using insulator gaps [2] or dielectrics patterned on the collector [3]. However, the alignment of successively smaller-sized electrospun nanofibers to a high degree is challenging, since smaller fibers experience larger distortions arising from their greater flux and their longer time within the instability region. Furthermore, they are more easily disrupted under shear forces due to alignment using mandrel-based mechanical approaches. Herein, we explore the optimization of electrical methods to enhance the effectiveness of alignment of sub-100 nm fibers through methodologies to vary the transverse field along the nanofiber axis and repulsive fields between neighboring nanofibers due to their residual charge [4]. In this manner, we present a quantitative design methodology for optimizing collector properties, such as gap width, material and permittivity to optimize the spatial extent of the transverse fields, as well as charge density and dielectric properties of the electrospun material to optimize repulsive fields due to residual charge. The application of nanofiber scaffolds aligned through these methods presents a tremendous potential for nerve tissue regeneration [5].

[1] Matthews, J. A.; Wnek, G. E.; Simpson, D. G.; Bowlin, G. L. Electrospinning of collagen nanofibers. Biomacromolecules 2002, 3, 232.

[2] Li, D.; Wang, Y.; Xia, Y. Electrospinning nanofibers as uniaxially aligned arrays and layer-by-layer stacked films. Adv. Mater. 2004, 16, 361.

[3] Yan, H.; Liu, L.; Zhang, Z. Alignment of electrospun nanofibers using dielectric materials. Applied Physics Letters 2009, 95 (14), 143114-1431-3.

[4] V. Chaurey, P. Chiang, C. Polanco, R. Su, C.F. Chou, N. Swami. “Interplay of electrical forces for alignment of sub-100 nm electrospun nanofibers at insulator gap collectors”, Langmuir (2010), 26 (24), pp 19022–19026.

[5] Neal, R.; Tholpady, S.; Foley, P.; Swami, N.; Ogle, R.; Botchwey, E.; “Alignment and composition of laminin-polycaprolactone nanofiber blends enhance peripheral nerve regeneration”, Journal of Biomedical Materials Research: Part A (2011), 100, 406-423.

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