(647f) Template Assisted Micro-Patterned Electrospun Nanofibrous Mat As a Potential Carrier for Controlled Drug Release

Controlled drug release by
manipulating the surface wettability and degradability of the drug carrier is
essential for medical treatments.¹Usually,
the wettability of a surface can be altered
by surface coatings and by changing the surface roughness. In this work we have
fabricated micro-patterned cellulose acetate electrospun nanofibrous mats using
template assisted electrospinning (Figure 1A). This approach produces mats with
tunable wettability. Nylon meshes (Figure 1B) with different grid spacing (50
µm, 100 µm and 200 µm) were used as a template to fabricate micro-patterned nanofabric over a large area (10 × 10 cm²) in a single step. This non-conductive nylon mesh in strong electrostatic
field polarizes and generates a negative static charge on the nylon mesh by
static induction and polarization.²Further,
the nylon grid attracts fibers onto grid
lines and forms micropatterned fiber
mats as shown in Figure 1 (A). Initially, fibers are preferably deposited on
nylon grid lines. After 10 min of deposition, the fibers repel incoming material
resulting in a random deposition to yield micro-patterned nanofabric surfaces as shown in Figure 1C.

Water contact angle measurements were
performed on these micro-patterned nanofibrous mats fabricated with different
spacing to study the effect of micropatterning on wettability.
As shown in Figure 1C, these micro-patterned surfaces form non-communicating
air gaps and air trapped in this gaps minimizes the solid-water interface and
opposes wetting by capillary action. This non-wetting pressure plays a key role in the wettability of non-commuting
air trapped systems.³ The Water Contact Angle (WCA) changes from 30°
for the non-patterned surface to 138° for
a micro-patterned surface with a 50 µm spacing. This change in WCA can be
attributed to capillary pressure increases with decreasing spacing. WCA
measurements are summarized in Figure 1D.

Further, the effect of surface wettability on drug release kinetics was investigated
by loading Diclofenac sodium into cellulose acetate precursor solutions prior
to electrospinning. Transdermal drug releases study
shown a significant change in drug
release kinetics with a change in surface
wettability. Micro-patterned surfaces with a WCA of 138° showed zero order
release kinetics up to 12 hours, whereas non-patterned hydrophilic (30°)
samples only showed controlled drug release for 1 hr.

References:

1.      Ajiro, H., Takahashi, Y., Akashi, M. and  Fujiwara T. Polymer, 2014, 55, 3591-3598.

2.      Zhao, S., Zhou, Q., Long, Y.Z., Sun, G.H. and Zhang, Y. Nanoscale
2013, 5, 4993-5000.

3.      Dash, S., Alt, M. T. and Garimella, S. V. Langmuir, 2012,
 28, 9606-9615.

4.      Kakunuri, M., Khandelwal, M., Sharma, C.S., Eichhorn, S.J. Materials Letters, 2017, 196, 339-342.

5.      Kakunuri, M., Wanasekara, N.D., Sharma, C.S., Khandelwal, M.,
Eichhorn, S.J. J. Appl. Poly. Sci., 2017, 134, 44709.