University of California, IrvineThe Integrated Micro/Nano Summer Undergraduate Research Experience

(IM-SURE)

Single-Cell Platforms for Microbiomechanics

Minh Guong Nguyen

Biomedical EngineeringUniversity of California, Irvine

Mentor: Professor William C. Tang Grad Student: Yu-Hsiang (Shawn) Hsu

OUTLINE

• Background– cytoskeleton– purposes

• Introduction– QCM– our piezoelectric transducer

• My responsibilities– design and develop experiments

– collect and analyze resulting data

• Problems and future work

CYTOSKELETON COMPONENTS

Intermediate filaments

Fig. 1: Three types of protein filaments form the cytoskeleton

Intermediate filaments Microtubules Actin filaments

protect cells and tissues from disintegration by mechanical stress

essential component of cell division

responsible for cell migration

Alberts, Bruce, et al. Essential Cell Biology. 2nd ed. New York & London: Garland Science, 2004

ACTIN FILAMENTS

Alberts, Bruce, et al. Essential Cell Biology. 2nd ed. New York & London: Garland Science, 2004

Fig. 2: Forces generated move a cell forward

WHY SINGLE-CELL PLATFORMS ?

PURPOSE

– mechanical changes of the cytoskeleton

– parallel drug screening

– cancerous cells identification and qualification

– others

COMPARISONTraditional Method Our method

Fig 3: Sketch of the quartz crystal microbalance (QCM) experimental setup

Fig. 4: A Single Cell Platforms for Microbiomechanics

chamber

cell

• Cannot detect 1 single cell mechanical property

• Not a precise result

• Detect 1 single cell mechanical property

• A precise result

Jing Li, Christiane Thielemann, Ute Reuning, and Diethelm Johannsmann. “Monitoring of integrin-mediated adhesion of human ovarian cancer cells to model protein surfaces by quartz crystal resonators: evaluation in the impedance analysis mode.” BioSensors & BioElectronics 20 (2005): 1333-1340.

Online posting. http://www.wctgroup.eng.uci.edu/

EXPERIMENTAL SETUP

Picture is taken by Minh Guong Nguyen, BME student, UCI

The probe

The Agilent 4395A

SiO2

ZnO

CROSS SECTION OF OUR DEVICE

Cross section of our device, drawing by Yu-Hsiang (Shawn) Hsu, Ph.D candidate, Dept of BME, UCI

Si

Au

200 µm

Au

cell

TOP VIEW OF OUR DEVICE

Units in

mm

200 µm in Diameter(our device)

1 mm square top electrode

15 µm thin lines

Top view of our device, drawing by Yu-Hsiang (Shawn) Hsu, Ph.D candidate, Dept of BME, UCI

OUR DEVICE’S IMPEDANCES

Resonance frequency

Anti-resonance frequency

Impedance

(Ω

)

Frequency (MHz)

Fig. 6: The graphs Impedance vs. Frequency of our device

Data is collected by our experiments

Impedance vs. Frequency

Resonance frequency

Anti-resonance frequency

THE QUALITY FACTOR

• QM: The quality factor• fa: The anti-resonance frequency (MHz)• fr: The resonance frequency (MHz)• Zr: The impedance at resonance frequency (Ω)• C: The static capacitance (pF)

http://www.morganelectroceramics.com/tutorials/piezoguide15.html

22

2

2 rarr

aM

ffCZf

fQ

TABLE OF VALUES OF OUR DEVICES

Device Anti-resonance frequency fa

(MHz)

Resonance frequency fr

(MHz)

Impedance at resonance

frequency Zr

(Ω)

Static capacitance

C (pF)

6-A 5.562 5.081 1689.3 25

7-A 5.499 5.085 1063.9 25

8-A 5.531 5.094 1084.7 25

8-B 5.540 5.112 1059.6 25

9-B 5.522 5.103 1062.6 25

10-B 5.522 5.103 1057.2 25

2-C 5.558 5.103 1232.0 25

4-C 5.531 5.094 1325.1 25

5-C 5.526 5.085 1271.4 25

Data is collected by our experiments

THE QUALITY FACTORS (QM) OF OUR DEVICES

The average

is 7.3585

Calculation is based on our data obtained from experiments

Device Quality factors (QM)

7-A 8.1209

8-A 7.5990

8-B 7.9203

9-B 8.0410

10-B 8.0911

2-C 6.4500

4-C 6.2203

5-C 6.4259

22

2

2 rarr

aM

ffCZf

fQ

COMPARISION OF OUR DEVICE WHEN TREATED WITH AND WITHOUT WATER

The graph is based on our data collected form experiments

320

340

360

380

400

420

440

460

33.0 34.0 35.0 36.0 37.0 38.0 39.0 40.0

Fig. 8: Comparison of our device when treated with and without water

Frequency (MHz)

Impedance

(Ω

)

Impedance vs. Frequency

Without WaterWith Water

DATA ANALYSIS

Device Resonance frequency fr (MHz)

Anti-resonance frequency fa (MHz)

Impedance at resonance frequency Zr

(Ω)

Viscosity (cP)

Quality factor QM

Frequency shift

Without water

3.6144 3.8141 350.17 0.0185 (air)

4.933 0.26

With water

3.6050 3.8366 333.74 0.982 4.519

The frequency shift is related to the weight of water.

The quality factor is related to the viscosity of water.

PROBLEMS AND FUTURE WORK

390

410

430

450

470

490

510

23 24 25 26 27Frequency (MHz)

W11-0W6-1W6-0WA6-REFW10-0

Fig. 10: Graph of impedance vs. frequency

Impedance

(Ω

)

Impedance vs. frequency

Frequency (MHz)

Impedance vs. Frequency

Impedance

(Ω

)

Fig. 11: Graph of impedance vs. frequency

B A DG O O D

Noise interferes the signal

ACKNOWLEDGEMENTS

• Dr. William C. Tang• Yu-Hsiang Hsu and John Lin• Wyman Wong

ALL FOR YOUR SUPPORT

• Said M. Shokair• Edward M. Olano• Sarah R. Martin• UROP Fellows

• National Science Foundation

QUESTIONS?

Back up slide

Comparison of our device when treated with and without water

Back-up slideIm

pedance

(Ω

)

Frequency (MHz)

The graphs of impedance vs. frequency of our devices zoom-in

Impedance vs. Frequency

ω = 2 () (f)

Impedance of Capacitor:

Zc =

Impedance of Inductor:ZL = j ω L

Impedance of Resistor:ZR = R

Butterworth-Van-Dyke (BVD) equivalent circuit

Fig 6: The BVD equivalent circuit

Inductor

Resistor

Capacitor

Capacitor

Joachim Wegener, Jochen Seebach, Andreas Janshoff, and Hans-Joachim Galla. « Analysis of the Composite Response of Shear Wave Resonators to the Attachment of Mammalian Cells.» Biophysical Journal. Volume 78. June 2000: 2821-2833.

Fig. 7: Lumped-element equivalent circuit