. tens of kilo-volts and provides randomly coiled fibers

. caused to try to have this kind of shape have been 22 and spiral turning capabilities
in soft robots 21, spiral-like electrodes
for energy harvesting 20, spiral molds to
specify the action of polymers injected on fabrics 19microarrays with spiral channels for numerous
hybridization rates . spiral patterns are detected
widely in nature and art. Benefits of this type of shape such as 18. Near field
electrospinning (NFES) has been used to achieve a nanofiber instead of randomly
nanofibers by decreasing spinneret to collector distance in electrospinning 17. the width of deposite nanofibers
distribution area is changed by varying the collector material and this area of
the silicon surface is smaller than that on SiO2 surface 16. different methods are
applied to fabricate hollow needles such as the combination of deep etching of
silicon substrates and rotating small angle deposition 15. Electrospinning
process is done by micromachining spinneret to form the nanofibers 14 and stimulate the
nervous signals 13, three-dimensional
measurement 12, blood extraction 11, transfer of DNA
solution to the core 10. So needle with the
small diameter is beneficial to electrospun nanofibers. Micro-electromechanical
systems (MEMS) technology has been applied to many types of research. Microneedle
array has been fabricated by using this technology. Microneedles have found
some applications in cancer treatment 9. Also, a lesser needle
diameter is conduced to have the bead free fibers and the beads are produced
due to  instability of the jet initiation
8 effect on the electrospinning
process. The smaller diameter of fibers is created by the minor diameter
capillaries 2. many parameters such
as polymer concentration, solution viscosity and conductivity, the applied
voltage, needle to collector distance, solution flow rate, needle diameter and
temperature and humidity of environment 7. conventional
electrospinning process acts at high voltages above the tens of kilo-volts and
provides randomly coiled fibers because of the turning instability of fiber jet
6 and MEMS device 5, bio-scaffolds 4, optical tools 3Such as filtration
membranes 2. nanofibers have great
characteristics such as smaller diameter, high surface-to-volume ratio and long
length that use in various industrial and scientific fields1Electrospinning is a beneficial process to fabricate
nanofibers of which the diameter ranging from tens to hundreds of nanometers
from polymer solutions at circumstance temperature and atmospheric pressure