# US 11,029,285 B2 · Real-time and quantitative measurement method for cell traction force

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- Number: US 11,029,285 B2
- Document ID: US11029285B2
- Status: Granted
- Kind: B2
- Application number: 16/336,883
- Filed: 2017-08-28
- Published: 2019-10-17
- Granted: 2021-06-08
- Earliest claimed: 2016-08-29
- Assignees: Hunan Agricultural University
- Applicants: Hunan Agricultural University
- Inventors: Tiean Zhou; Lun Xiong; Zhen Zhou; Jingyuan Huang; Haibo Shen; Dongqin Bao; Fushen Huang; Kebin Wu; Weisong Pan; Jia Zhao; Bin Hong
- Web page: https://patentgrep.com/patent/US11029285B2

## CPC

- G01N 29/022: {Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B)}
- G01N 29/12: by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)}
- C12N 5/04: Plant cells or tissues {(culture media C12N5/0025)}
- C12N 5/06: {Animal cells or tissues; Human cells or tissues (preservation of excised living parts A01N1/10)}
- G01N 29/036: by measuring frequency or resonance of acoustic waves
- G01N 29/2443: {Quartz crystal probes}
- G01N 33/4833: {of solid biological material, e.g. tissue samples, cell cultures (tissue in vivo A61B5/00; cell suspensions G01N33/48735)}
- G01N 2291/02466: Biological material, e.g. blood
- G01N 2291/0256: Adsorption, desorption, surface mass change, e.g. on biosensors
- G01N 2291/02827: Elastic parameters, strength or force
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)

## Abstract

A real time and quantitative method of measuring traction force of living cells include the following procedures. Place AT-cut and BT-cut quartz crystals of the same frequency, surface morphology and/or modified with the same cell adhesion molecules in petri dishes or detection cells; add the cells to the petri dishes or detection cells, the cell traction force at arbitrary time t during adhesion of the cells or under different internal/external environmental stimulations is estimated by the following equation: ΔSt=(KAT−KBT)−1[tqATΔftAT/frAT−tqBTΔftBT/frBT]. The method can be used to track the dynamic changes of cells generated force during the adhesion of cells and under different internal/external environmental stimulations, such as the effects of drugs. The drugs can be added before or after the adhesion of the cells. This method is suitable for all adherent cells, including primary cells and passage cells.

## Claims

### Claim 1

A real-time and quantitative measurement method for cell traction force, comprising the following steps:
(1) placing an AT-cut quartz crystal and a BT-cut quartz crystal in culture dishes or detection cells, wherein the AT-cut quartz crystal having the same frequency, surface morphology and/or modified surface adhesion molecules as those of the BT-cut quartz crystal; and
(2) adding cells to be tested to the culture dishes or the detection cells, and measuring the cell traction force ΔSt of the cells at an adhesion time t by the following formula:
ΔSt=(KAT−KBT)−1[tqATΔftAT/frAT−tqBTΔftBT/frBT] (1),
wherein KAT=2.75×10−12 cm2 dyn−1 and KBT=−2.65×10−12 cm2 dyn−1 are stress coefficients of the AT-cut quartz crystal and the BT-cut quartz crystal respectively; frAT is the resonant frequency of the AT-cut quartz crystal, frBT is the resonant frequency of the BT-cut quartz crystal, tqAT is the thickness of the AT-cut quartz crystal, tqBT is the thickness of the BT-cut quartz crystal, and all of which are constants; ΔftAT and ΔftBT are the frequency shifts of the AT-cut and BT-cut quartz crystals at any time t relative to their reference points respectively;
when ΔSt is negative, it indicates that the stress on the cells is a compressive stress, the cells are contracted, and the corresponding extracellular matrices are subjected to a tensile stress equal and opposite to the compressive stress; when ΔSt is positive, the stress on the cells is a tensile stress, the cells are spread, and the corresponding extracellular matrices are subjected to a compressive stress equal and opposite to the tensile stress.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the cell adhesion molecules comprise extracellular matrix molecules capable of interacting with transmembrane proteins and integrins; extracellular matrix biomimetic molecules capable of interacting with transmembrane proteins and integrins; molecules capable of interacting with cell surface receptors; and molecules interacting with the surface of cells to promote cell adhesion.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the extracellular matrix molecules capable of interacting with transmembrane proteins and integrins are fibronectin, laminin, vitronectin or collagen; the extracellular matrix biomimetic molecules capable of interacting with transmembrane proteins and integrins are RGD adhesion sequence polypeptides; the molecules capable of interacting with cell surface receptors are molecules capable of interacting with cell surface cadherin; and the molecules interacting with the surface of cells to promote cell adhesion are poly-l-lysine.

### Claim 4 (depends on 1)

The method according to claim 1, wherein in the formula of step (2), tqAT=0.1661/frAT; and tqBT=0.2536/frBT.