2. Research goals and Questions
Research proposal
충남대학교 응용화학공학과 202250364 손희성
The purpose is droplet generation for single
cell encapsulation. And this research goal is
development
Laboratory: Nano/microbiosystem
of
high-speed
and
accurate
sorting system
Adviser: Lee, chang-soo (충남대학교)
But I concern that the droplet containing PPy
Cowork: Sanghyuk Wooh (중앙대학교)
could move or not by using short time
irradiation of CO2 laser on microfluidic device.
It needs to experimental research.
Title: Strategy of a microfluidic sorter via
light-driven Marangoni propulsion
3. Research plans
1. Introduction and Backgrounds
As I mention on introduction, our goal is
As single cell analysis and cultivation, we
have simply used encapsulation by generating
droplets. In our lab, we have employed a
system for sorting droplets [1-3] that is
pneumatic valve for single cell analysis. It has
been
throughout
the
problems
like
low
throughput and low accuracy of previous
works. And this throughput is 50 Hz and
accuracy is about 98.9 % [4]. As my opinion,
this limitation comes from the fundamental
system that consists fluidic controller. And this
accompanies time delay.
ultimately single cell level of analysis and
cultivation. For the generation of droplets, the
device will consist of oil on continuous phase
and PPys with cells. The chip will generate
droplets containing cell. Because of getting
empty droplets is inevitable. We will sort only
droplets that contain cell which is having
fluorescence molecule. We will spot the signal
of droplet from downstream following droplet
generation. If the droplet has the cell, the
system
that
connected
with
high-speed
camera will recognizes the signal, then CO2
laser will irradiate to topside of droplet. The
So, I insist if the system is substituted with
droplet would move on to upside for sorting.
light source like CO2 laser that is proposed by
For the improvement of this sorting efficiency,
Prof. Wooh. for driving droplets [5], we would
we could consider the dean flow design.
increase the throughput and accuracy for
because of the flow in the channel on
sorting droplets.
He shows a drop that
microfluidic device is laminar flow, if the
containing PPys(polypyrole nanoparticles) can
stream is divided to two ways, the molecule
move to where we intend by irradiation that
on the stream also will separate. For example,
CO2 laser which induce partially thermal
we separate the stream to exactly half. And it
heating PPys containing droplet. Following
would be relatively upside, then the droplet
movement of PPys on droplet, the Marangoni
will be sorted upper.
propulsion occurs [6]. As a result, the droplet
moves to opposite side where CO2 laser
irradiates [7].
4. Timeline
If we perform this research, we must design
the
device
and
check
the
possibility
of
movement of droplet by irradiation time of
CO2 laser. And for setting up automatic
analysis, programming like the Labview must
8. Personnel
This proposal is just for the report. But if there
is possibility, we could collaborate for this.
be designed for transferring signal from cell’s
9. Reference
fluorescence signal to CO2 laser irradiation
[1] Kim, C., et al. (2017). "Microfluidic synthesis of
monodisperse pectin hydrogel microspheres based on in
situ gelation and settling collection." Journal of Chemical
Technology & Biotechnology 92(1): 201-209.
going through computer.
5. Materials
High-speed camera with microscopy, syringe
pump,
photoresist
polydimethylsiloxane
(SU8
3025)
(PDMS)
for
and
device
fabrication. HFE 7500 oil and Picosurf for
making emulsion droplets. phosphate buffered
saline (PBS). 2-NBDG, a fluorescent analog of
glucose, Fluorescein sodium salt, alginic acid,
acetic acid, Optiprep.
6. Expected application
In our lab, several researchers work on single
cell
cultivation
of
Escherichia
coli,
Staphylococcus aureus, etc. that expresses red
or green fluorescent protein. We can test
single cell encapsulation and sort by this
method
if
applications,
it
works
various
out.
As
following
experiments
could
perform like cell cultivation [8] and analysing
cell to cell communication [9] or antimicrobial
susceptibility testing [10].
7. Budget
Our lab already has most of set up for
droplet sorter. But we would connect the CO2
irradiator. As I remember the prof. Wooh said
we can buy commercial product which has
beam of specific power.
Totally we would buy the CO2 laser and
composition for this.
[2] Choi, C. H., Weitz, D. A., & Lee, C. S. (2013). One step
formation of controllable complex emulsions: from
functional particles to simultaneous encapsulation of
hydrophilic and hydrophobic agents into desired
position. Advanced materials, 25(18), 2536-2541.
[3] Jang, S., Lee, B., Jeong, H. H., Jin, S. H., Jang, S., Kim, S.
G., ... & Lee, C. S. (2016). On-chip analysis, indexing and
screening for chemical producing bacteria in a microfluidic
static droplet array. Lab on a Chip, 16(10), 1909-1916.
[4] Jin, S. H., Lee, B., Kim, J. S., & Lee, C. S. (2021).
Improvement strategy of a microfluidic sorter using a
pneumatic
bilayer
valve. Chemical
Engineering
Science, 245, 116834.
[5] Hwang, H., Papadopoulos, P., Fujii, S., & Wooh, S.
(2022). Driving Droplets on Liquid Repellent Surfaces via
Light‐Driven Marangoni Propulsion. Advanced Functional
Materials, 32(15), 2111311.
[6] a) M. Paven, H. Mayama, T. Sekido, H.-J. Butt,
Y. Nakamura, S. Fujii, Adv. Funct. Mater. 2016, 26, 3199; b)
H.
Kawashima,
M. Paven,
H. Mayama,
H.-J. Butt,
Y. Nakamura, S. Fujii, ACS Appl. Mater. Interfaces 2017, 9,
33351; c) F. Li, M. A. Winnik, A. Matvienko, A. Mandelis, J.
Mater. Chem. 2007, 17, 4309; d) K. M. Au, M. Chen, S.
P. Armes, N. Zheng, Chem. Commun. 2013, 49, 10525.
[7] Wooh, S., & Butt, H. J. (2017). A Photocatalytically
Active
Lubricant‐Impregnated
Surface. Angewandte
Chemie, 129(18), 5047-5051.
[8] Jeong, H. H., Jin, S. H., Lee, B. J., Kim, T., & Lee, C. S.
(2015). Microfluidic static droplet array for analyzing
microbial communication on a population gradient. Lab
on a Chip, 15(3), 889-899.
[9] Jin, S. H., Lee, S. S., Lee, B., Jeong, S. G., Peter, M., &
Lee, C. S. (2017). Programmable static droplet array for the
analysis of cell–cell communication in a confined
microenvironment. Analytical chemistry, 89(18), 9722-9729.
[10] Kim, K. P., Kim, Y. G., Choi, C. H., Kim, H. E., Lee, S. H.,
Chang, W. S., & Lee, C. S. (2010). In situ monitoring of
antibiotic susceptibility of bacterial biofilms in a
microfluidic device. Lab on a Chip, 10(23), 3296-3299.