13-06-2012, 01:14 PM
Nano Micro Robotics and its Application to Bio Science and Technology
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Introduction
Cloning technology, that allows production of the
genetically identical offspring of another organism, has
wide variety of applications in agriculture, pharmacy,
regenerative medicine, etc. It is one of the most promising
technologies in the bioscience and technology. The current
cloning technology includes extraction of nucleus,
injection or electric cell fusion of donor nucleus. All the
processes are performed by skillful manual operation
typically using micromanipulator with optical microscope.
An operator requires time-consuming training to obtain
the required manipulation skills. The success rate in
obtaining a normal birth from cloned embryos remains
extremely low around a few percent.
New Protocol and System Configuration
The new protocol consists of several simple processes
including (1) removal of zona pellucida, (2) oocyte
bisection, (3) separation of enucleated demi-oocyte, (4)
donor cell coupling, and (5) electric fusion [1]. All
processes are performed in micro flow on small substrate
composing what we call a “desk-top bio plant”.
Separation and sort module
Enucleated cell part is separated and sorted for use in
further cloning process. A separator is composed of a
Y-shape channel and micro magnetic tool [4]. The tool is
actuated by electromagnetic coil, switches flows, and sorts
cell and particle as shown in Fig.4.
Coupling module
A donor cell (fibroblast) is adhered on the surface of
demi-oocyte by dielectrophoresis (DEP). First, a
demi-oocyte is caught in the middle of main channel
(Fig.5(a)), then a donor cell is fed from tributary channel
and drawn to the oocyte surface by DEP (Fig.5(b)).
Fusion module
A coupled oocyte and donor cell is aligned by DEP
(8Vp-p@1MHz) between two parallel micro electrodes
separated in 400um distance. The electrodes are made
from thin nickel plates and filled in the PDMS surface to
compose a channel. Fusion is achieved by applying DC
pulse
Fabrication and sensing
Every module is fabricated with PDMS by
photolithography technique. Male mold is patterned and
fabricated by spin-coated SU8 lithography. Mountable
particle detection sensor and microscope [5] are also
developed for module.
Conclusions
We have confirmed basic function of every module
with biological evaluation, i.e. growth rate and safety. All
in one chip (Fig.7) is developed [6] to demonstrate every
process of cloning to achieve “desk top bio-plant”.