while generating “electrophoresis” within the nanochannel, which
can prominently drive genes (carrying surface charge) into the
aligned cells. Theoretically, when a biased voltage is applied over
the nanochannel and cells shown in Fig. 1, more than 90% potential
drop will be distributed over the nanochannel while less than 10%
over the cell membrane, due to the fact that the equivalent resistance of the nanochannel (in ionic solution) is significantly higher
than that of the cell membrane. As most cargo carry surface
charges, the potential across the nanochannel will cause dominant
electrophoresis. The total delivery procedure is accomplished
within the duration of the short electric pulses. The mechanism is
more precise for single cell, as compared to all other reported
systems, while the delivery procedure performs a unique dose
control and single-cell uniformity, promising high delivery efficiency and cell viability. The density of the nanochannel array is
designed based on the cell size and electric field strength. On our
3D NEP device, each chip offers more than 40,000 cells per cm
2 .
Million cells are achieved in parallel by an up-scaled device with 4-in
area.
In NEP, only the cell juxtaposed with the nanochannel could be
electroporated. To achieve high transfection efficiency, highthroughput cell manipulation techniques capturing cells on the
nanochannel array are demanded. The capability of safely aligning
a large number of individual cells with an array of nanochannel not
only determines the NEP transfection efficiency but also supports
on-chip comprehensive analysis of single cells in vitro. We herein
briefly introduce three high-throughput cell manipulation techniques which have been successfully demonstrated on the 3D NEP
device, including magnetic tweezers (MT) [14], dielectrophoresis
(DEP) [15], and thin-film microfluidics [16].
The basic MT setup [17] consists of four orthogonal electromagnets (for X, Y fields) and a solenoid (for Z fields) surrounding
the nanochannel array chip and providing a nearly uniform magnetic field over the array of nanochannels on the NEP chip
(Fig. 2a). To manipulate [18] the individual cells in parallel, an
array of permalloy disks was patterned on the nanopore chip. Weak
(<150 G) external in-plane magnetic fields H XY ¼ H X + H Y are
created by four orthogonal electromagnets and the out-of-plane
field H Z is produced by a surrounding solenoid. Each field source
(H X , H Y , H Z ) is controlled by a separate current channel. The
permalloy magnetic disks magnetize in the direction of H XY , creating either attractive traps (magnetic potential energy wells) or
repulsive centers whose strengths are tuned with H Z [14]. Each
disk captures a single magnetically labelled cell. Simple programmable routines that rotate H XY and revers H Z are used to transport
the labelled cells to electroporation sites. The cells are subsequently
maneuvered across the platform.
3D Nanochannel Array for High-Throughput Cell Manipulation and Electroporation
31
can prominently drive genes (carrying surface charge) into the
aligned cells. Theoretically, when a biased voltage is applied over
the nanochannel and cells shown in Fig. 1, more than 90% potential
drop will be distributed over the nanochannel while less than 10%
over the cell membrane, due to the fact that the equivalent resistance of the nanochannel (in ionic solution) is significantly higher
than that of the cell membrane. As most cargo carry surface
charges, the potential across the nanochannel will cause dominant
electrophoresis. The total delivery procedure is accomplished
within the duration of the short electric pulses. The mechanism is
more precise for single cell, as compared to all other reported
systems, while the delivery procedure performs a unique dose
control and single-cell uniformity, promising high delivery efficiency and cell viability. The density of the nanochannel array is
designed based on the cell size and electric field strength. On our
3D NEP device, each chip offers more than 40,000 cells per cm
2 .
Million cells are achieved in parallel by an up-scaled device with 4-in
area.
In NEP, only the cell juxtaposed with the nanochannel could be
electroporated. To achieve high transfection efficiency, highthroughput cell manipulation techniques capturing cells on the
nanochannel array are demanded. The capability of safely aligning
a large number of individual cells with an array of nanochannel not
only determines the NEP transfection efficiency but also supports
on-chip comprehensive analysis of single cells in vitro. We herein
briefly introduce three high-throughput cell manipulation techniques which have been successfully demonstrated on the 3D NEP
device, including magnetic tweezers (MT) [14], dielectrophoresis
(DEP) [15], and thin-film microfluidics [16].
The basic MT setup [17] consists of four orthogonal electromagnets (for X, Y fields) and a solenoid (for Z fields) surrounding
the nanochannel array chip and providing a nearly uniform magnetic field over the array of nanochannels on the NEP chip
(Fig. 2a). To manipulate [18] the individual cells in parallel, an
array of permalloy disks was patterned on the nanopore chip. Weak
(<150 G) external in-plane magnetic fields H XY ¼ H X + H Y are
created by four orthogonal electromagnets and the out-of-plane
field H Z is produced by a surrounding solenoid. Each field source
(H X , H Y , H Z ) is controlled by a separate current channel. The
permalloy magnetic disks magnetize in the direction of H XY , creating either attractive traps (magnetic potential energy wells) or
repulsive centers whose strengths are tuned with H Z [14]. Each
disk captures a single magnetically labelled cell. Simple programmable routines that rotate H XY and revers H Z are used to transport
the labelled cells to electroporation sites. The cells are subsequently
maneuvered across the platform.
3D Nanochannel Array for High-Throughput Cell Manipulation and Electroporation
31