Screening method for high-efficiency biofuel-producing strains by dielectrophoretic method using vertical nano-gap electrodes

Patent metadata

Field	Value
Publication number	US-11285492-B2
Application number	US-201916393967-A
Country	US
Kind code	B2
Filing date	Apr 25, 2019
Priority date	Dec 17, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

Disclosed herein are a screening method of high-efficiency biofuel-producing strains by a dielectrophoretic method using vertical nano-gap electrodes and a producing method of biofuel from the screened strains.

First claim

What is claimed is:

1. A screening method of biofuel-producing strains comprising:
a first step of introducing a fluid containing a biofuel-producing strain candidate group to an apparatus including a layered structure including a first conductor layer; an insulator layer having a constant thickness selected from a range of 5 nm to 1000 nm; and a second conductor layer which are stacked sequentially as a dielectrophoretic electrode pair and a circuit electrically connected with an AC power supply unit, in which holes commonly penetrating both the insulator layer and the second conductor layer are defined in the insulator layer and the second conductor layer in a regular pattern, a shape and a size of part of the hole included in the insulator layer are the same as a shape and a size of part of the hole included in the second conductor layer at a corresponding position, and the first conductor layer is continuous and does not have a hole at the corresponding position, and disposing the fluid to contact with an upper surface of the first conductor layer and inside the holes;
a second step of applying an AC voltage between the first conductor layer and the second conductor layer; and
a third step of selectively recovering cells trapped in holes of the electrode pair.

2. The screening method of claim 1 , wherein the holes have each independently an area of 50 nm 2 to 10,000 μm 2 .

3. The screening method of claim 1 , wherein the AC derives a Clausius-Mossotti (CM) curve according to an applied AC frequency with respect to a strain to be trapped using Equation 1 below and has a frequency selected in a range where a real part of the Clausius-Mossotti in the derived curve is a positive value:

f
CM

⁡

(
ω
)

=

ɛ
p
*

⁡

(
ω
)

-

ɛ
m
*

⁡

(
ω
)

ɛ
p
*

⁡

(
ω
)

+

2
⁢

ɛ
m
*

⁡

(
ω
)

[

Equation
⁢

⁢
1

]

in Equation above,
ω is a frequency of the AC applied to the dielectrophoretic electrode pair,
ε* p is the permittivity of the particles to be trapped, and
ε* m is the permittivity of the fluid.

4. The screening method of claim 1 , wherein the AC is applied at a frequency of 10 kHz to 10 MHz and a voltage of 0.1 V to 5 V.

5. The screening method of claim 1 , wherein the cells trapped in the holes in the third step are strains having a relatively high lipid content.

6. The screening method of claim 1 , wherein the biofuel-producing strain is a lipid-producing microorganism or a variant thereof.

7. The screening method of claim 1 , wherein the first conductor layer and the second conductor layer are each independently made of metal selected from the group consisting of copper, gold, silver, platinum, and palladium; alloys or complexes containing at least one metal selected from the group consisting of copper, gold, silver, platinum, and palladium and at least one material selected from the group consisting of tellurium, tungsten, zinc, iridium, ruthenium, arsenic, phosphorus, aluminum, manganese, and silicon; conductive carbon materials selected from the group consisting of graphite, graphene, and derivatives thereof; or mixed metal oxides selected from the group consisting of indium tin oxide (ITO), titanium oxide (TiO 2 ), ruthenium oxide (RuO 2 ), iridium oxide (IrO 2 ), and platinum oxide (PtO 2 ).

8. The screening method of claim 1 , wherein the insulator layer is made of a material selected from the group consisting of SiO 2 , polyvinylpyrrolidone (PVP), Nb 2 O 5 , TiO 2 , Al 2 O 3 , and MgO.

9. A producing method of biofuel comprising:
a first step of introducing a fluid containing a biofuel-producing strain candidate group to an apparatus including a layered structure including a first conductor layer; an insulator layer having a constant thickness selected from a range of 5 nm to 1000 nm; and a second conductor layer which are stacked sequentially as a dielectrophoretic electrode pair, and a circuit electrically connected with an AC power supply unit, in which holes commonly penetrating both the insulator layer and the second conductor layer are defined in the insular layer and the second conductor layer in a regular pattern, a shape and a size of part of the hole included in the insulator layer are the same as a shape and a size of part of the hole included in the second conductor layer at a corresponding position, and the first conductor layer in continuous and does not have a hole in the corresponding position, and disposing the fluid to contact with an upper surface of the first conductor layer and inside the holes;
a second step of applying an AC voltage between the first conductor layer and the second conductor layer;
a third step of selectively recovering cells trapped in holes of the electrode pair; and
a fourth step of culturing the cells selectively recovered from the third step.

10. The producing method of claim 9 , wherein the holes have each independently an area of 50 nm 2 to 10,000 μm 2 .

11. The producing method of claim 9 , wherein the AC derives a Clausius-Mossotti (CM) curve according to an applied AC frequency with respect to a strain to be trapped using Eq

Assignees

• Korea Inst Sci & Tech

Inventors

• Lee Sun Mi
• Ryu Yong-Sang
• Yu Eui-Sang
• Kim Jiwon
• Ko Ja Kyong
• Gong Gyeongtaek
• Kim Chulki
• Kim Jae Hun

Classifications

• B03C5/026

  using open-gradient differential dielectric separation, i.e. using electrodes of special shapes for non-uniform field creation, e.g. Fluid Integrated Circuit [FIC] · CPC title

• B03C5/005 Primary

  Dielectrophoresis, i.e. dielectric particles migrating towards the region of highest field strength · CPC title

• G01N27/44704 Primary

  Details; Accessories · CPC title

• Y02E50/10

  Biofuels, e.g. bio-diesel · CPC title

• G01N27/44756

  Apparatus specially adapted therefor · CPC title