Cell microinjection system with force feedback

Patent metadata

Field	Value
Publication number	US-11732275-B2
Application number	US-201916364458-A
Country	US
Kind code	B2
Filing date	Mar 26, 2019
Priority date	Mar 26, 2018
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A novel piezo-driven cell injection system with force feedback overcomes the unsatisfied force interaction between the pipette needle and embryos in conventional position control. By integrating semiconductor strain-gage sensors for detecting the cell penetration force and the micropipette relative position in real time, the developed cell microinjection system features high operation speed, confident success rate, and high survival rate. The effectiveness of the developed cell injection system is experimentally verified by penetrating zebrafish embryos. The injection of 100 embryos are conducted with separate position control and force control. Results indicate that the force control enables a survival rate of 86%, which is higher than the survival rate of 82% produced by the position control in the same control environment. The experimental results quantitatively demonstrate the superiority of force control over conventional position control for the first time.

First claim

The invention claimed is:

1. A microinjection system comprising:
a microinjector; and
a control device comprising:
a linear actuator which controls the movement of the microinjector towards and

from a pierceable microstructure target; and
position and force strain gauge sensors configured to provide position and force information including force feedback information for enabling making a determination of whether the pierceable microstructure target has been pierced,
wherein the force feedback information is provided to a controller which is operatively linked to said linear actuator,
wherein the control device further comprises a bridge displacement amplifier,
wherein at least one of the force strain gauge sensors is mounted on the bridge displacement amplifier, and
wherein at least another one of the force strain gauge sensors is mounted on the microinjector.

2. The microinjection system as claimed in claim 1 , wherein said controller comprises a proportional-integral-derivative controller.

3. The microinjection system as claimed in claim 1 , wherein said linear actuator is a piezoelectric actuator with the bridge displacement amplifier.

4. The microinjection system as claimed in claim 1 , wherein said force strain gauge sensors are semiconductor strain gauge sensors.

5. The microinjection system as claimed in claim 4 , wherein one of the force-strain gauge sensors is configured to control the force applied by the linear actuator to be sufficient to effect puncture of a target.

6. The microinjection system as claimed in claim 1 , wherein the microinjector is a micropipette and the microinjection system further comprises a flexure guiding mechanism for driving the micropipette to its intended location and for ensuring withdrawal of the micropipette with minimal damage to the pierceable microstructure target.

7. The microinjection system as claimed in claim 6 , wherein the controller is configured to exercise control over movement of the micropipette using sampling time intervals according to equation (3):
u ( t )= u ( t−T )+ K p [e ( t )− e ( t−T )]+ K i e ( t )+ K d [e ( t )−2 e ( t−T )+ e ( t− 2 T )]  (3)

where x is a position/force variable, x r denotes a desired position/force trajectory, T is the sampling time interval, e(t) is the position/force tracking error, u(t) denotes a control variable of the current time step, and u(t−T) denotes the control variable in the previous time step, and K p , K 1 and K d are tunable positive gains and e(t)=x (t)−x r (t).

8. A method for microinjection of a substance into a pierceable microstructure target which comprises:
(1) positioning a microinjector relative to the pierceable microstructure target by use of a charge coupled device camera using a computer vision algorithm;
(2) following the positioning of the microinjector relative to the pierceable microstructure target, effecting puncture of said pierceable microstructure by the microinjector; and
(3) introducing a substance into said pierceable microstructure by injection from said microinjector,
wherein motion of said microinjector is controlled by a control device comprising a linear actuator which controls movement of the microinjector towards and from said pierceable microstructure target and position and force strain gauge sensors configured to provide position and force information including force feedback information enabling making a determination of whether the pierceable microstructure target has been pierced to a controller which is operatively linked to said linear actuator whereby sufficient force is applied to the microinjector to effect piercing of the wall of the pierceable microstructure,
wherein the control device further comprises a bridge displacement amplifier,
wherein at least one of the force strain gauge sensors is mounted on the bridge displacement amplifier, and
wherein at least another one of the force strain gauge sensors is mounted on the microinjector.

9. The method as claimed in claim 8 , wherein control over the movement of the microinjector is effected by the controller according to the equation (3):
u ( t )= u ( t−T )+ K p [e ( t )− e ( t−T )]+ K i e ( t )+ K d [e ( t )−2 e ( t−T )+ e ( t− 2 T )]  (3)

where x is a position/force variable, x r denotes a desired position/force trajectory, T is the sampling time interval, e(t) is the position/force tracking error, u(t) denotes a control variable in the current time step, and u(t−T) denotes a control variable in the previous time step, K p , K 1 and K d are tunable positive gains and e(t)=x(t)−x r (t).

10. The method as claimed in claim 9 , wherein the force strain gauge sensors are calibrated to provide position and force information to the controller to determine said position/force variable.

11. The method as claimed in claim 8 , wherein said pierceable microstructure target is selected from the group consisting of such as a biological cells, nuclear envelopes and viral capsids and envelopes using such a piezoelectric actuator.

12. The method as claimed in claim 11 , further comprising which comprises introduction of DNA into a cell nucleus.

13. The method as claimed in claim 12 , wherein said introduction is effected as part of a gene therapy regimen.

14. The method as claimed in claim 8 , wherein DNA is introduced into a virus.

15. The method as claimed in claim 8 , wherein said pierceable microstructure target is an ovum or embryo.

16. The method as claimed in claim 15 , wherein said introduction is effected to effect in vitro fertilization of an ovum, cloning or insertion of cells, such as stem cells, into an embryo.

17. A control device suitable for use with an injector for injecting biological material into a pierceable microstructure, said control device comprising:
a linear actuator which controls the movement of the injector towards and from a pierceable microstructure target;
position and force strain gauge sensors configured to provide position and force information including force feedback information enabling making a determination of whether the pierceable microstructure target has been pierced to a controller which is operatively linked to said linear actuator; and
a bridge displacement amplifier,
wherein at least one of the force strain gauge sensors is mounted on the bridge displacement amplifier, and
wherein at least another one of the force strain gauge sensors is configured to be mounted on the injector.

Assignees

• Univ Macau

Inventors

• Xu Qingsong

Classifications

• C12N15/89 Primary

  using microinjection · CPC title

• A61D19/00

  Instruments or methods for reproduction or fertilisation · CPC title

• B01L3/56

  Labware specially adapted for transferring fluids · CPC title

• B25J7/00

  Micromanipulators {(specimen supports for investigating or analysing materials G01N23/2204; associated with microscopes G02B21/32; means for supporting or positioning the objects or the material in discharge tubes H01J37/20)} · CPC title

• B25J9/1633

  compliant, force, torque control, e.g. combined with position control · CPC title