Q-Sense Basic Training, April 4-5, 2006

Introduction and QCM-D Theory

Outline

• Q-Sense in brief• Introduction to QCM-D• The QCM-D (Quartz Crystal Microbalance

with Dissipation monitoring) principle• Q-Sense instruments

Brief history• 1976 Start of QCM-D research at Chalmers

• 1995 QCM-D patented

• 1996 Q-Sense AB founded

• 1998 spin-off, Ven Cap, personnel

• 1999 Product development, prototype sales

• 2000 Commercial focus, 1:st generation product launched

• 2001 US Subsidiary, Newport Beach, CA

• 2004 Systems in 23 countries, 100+ scientific publications

• 2005 2:nd Generation product launch, Q-Sense E4

• 2006 US Office moved to the east coast

Quick Facts• Swedish University Spin Off

• 15 Employees

• Turnover 2005, ~2.5 milion US$,

• Installed instruments in 23 countries,

• Subsidiary Q-Sense Inc. US,

• Distributor Network, Europe, Australia, Singapore, Japan, Korea

• Owners, Biolin AB, Stockholm Stock Exchange

• Scientific Network, 10 high impact research groups

Example of Customers• Harvard University, USA, Prof. Whitesides

• Stanford University, Prof Curtis Frank

• Rutgers University, Prof J. Kohn

• Procter and Gamble

• Medtronic, Inc.

• Cambridge University, UK, Prof. A. Donald

• Nippon Paper Industries, JP

• Max-Planck Institute, DE, Prof. W. Knoll

• Chalmers University of Technology, SE, Prof. B. Kasemo

QuartzQuartz is the only material known that possesses the following

combination of properties:

• Piezoelectric ("pressure-electric"; piezein = to press, in Greek)

• Zero temperature coefficient cuts exist

• Stress compensated cut exists

• Low loss (i.e., high Q)

• Easy to process; low solubility in everything, under "normal" conditions, except the fluoride etchants; hard but not brittle

• Abundant in nature; easy to grow in large quantities, at low cost, and with relatively high purity and perfection. Of the man-grown single crystals, quartz, at ~3,000 tons per year, is second only to silicon in quantity grown (3 to 4 times as much Si is grown annually, as of 1997).

John R. Vig, U.S. Army Communications-Electronics Command

QCM TimelineC

urie

bro

ther

s di

scov

er

piez

oele

ctric

ity

1880

Firs

t qua

rtz c

ryst

al

cont

rolle

d os

cilla

tor

1921 1959

Saue

rbre

y re

late

s

frequ

ency

and

mas

s

1980Fi

rst Q

CM

ope

ratin

g in

liqui

d

1996

QC

M-D

Pat

ent f

iled

Undeformed lattice

X++

++++

+++

++++++

+ +++++

____ __ ______ __

______Y

_

Strained lattice

+++

+++

+++

++++++

+ +++++

____ __ _______ __

______

••-+

Y

_

fn

Cm ∆−=∆ 1

Start as research tool

Sauerbrey

• German Scientist• ”Mandatory” reference

fn

Cm ∆−=∆ 1overtonen

sngcmC−= −− 127,17

Linear relationship between frequency and mass:

Sauerbrey, G Z. Phys. 155 (1959) 206

Military & AerospaceCommunicationsNavigationIFFRadarSensorsGuidance systemsFuzesElectronic warfareSonobouys

Research & MetrologyAtomic clocksInstrumentsAstronomy & geodesySpace trackingCelestial navigation

IndustrialCommunicationsTelecommunicationsMobile/cellular/portableradio, telephone & pager

AviationMarineNavigationInstrumentationComputersDigital systemsCRT displaysDisk drivesModemsTagging/identificationUtilitiesSensors

ConsumerWatches & clocksCellular & cordless

phones, pagersRadio & hi-fi equipmentColor TVCable TV systemsHome computersVCR & video cameraCB & amateur radioToys & gamesPacemakersOther medical devices

AutomotiveEngine control, stereo,

clockTrip computer, GPS

John R. Vig, U.S. Army Communications-Electronics Command

QCM Applications

The QCM-D sensor

Quartz

Gold Electrode

Gold Electrodediam. 14mm

5MHz

QCM-D ping principle

�f is related to the massof the attached film(Sauerbrey relation)

�D is related to theviscoelasticity

������������

QCM layout Metallicelectrodes

Crystal, sensor, QCM, QCN, TSR, TSO

Amplitude distribution, u

u

Active electrode (reaction substrate)

Counter electrode

Contact electrodes

The Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) technique

Time ( s)µ

A∆ ∝f

∆∆ ∝

mD stiffness

A(t)=A0⋅exp(-t/τ)⋅sin(2πft+φ)

D=1/πfτ

Mathematical representationof the decay curve

Frequency change (∆f):� adsorbed amount: ∆∆∆∆m=-C·∆∆∆∆f

(Sauerbrey equation)

Energy Dissipation (∆D):� rigidity

Multiple frequency modeling:� shear viscosity and elasticity

Dissipation factor (D)

• Definition

• D is the sum of all losses in the systemDtot = Dmounting + Delectronic + Detc + …

D ==== 1Q

==== energy dissipated per oscillation2ππππ total energy stored in system

Equivalent circuit of quartz crystal

Symbol for crystal unit CL

C1L1 R1

C0

CL

1

121RfL

QD

π==

Butterworth-Van Dyke Element (BVD)

What extra information does ��������

• Verify validity of Sauerbrey relation• Monitoring swelling/hydration• Viscoelastic modeling• Insight into structural changes

QCM Overtones

0

jX

-jX

Rea

ctan

ce

Fundamental mode3rd overtone

5th overtone

Frequency

Spuriousresponses Spurious

responses

Spuriousresponses

Overtone sensitivityPenetration Depth Overtones

0

50

100

150

200

250

300

-1,5 -1 -0,5 0 0,5 1 1,5

Normalized distribution

Pen

etra

tion

Dep

th (n

m) 1

3

5

7

9

11

13

15

5 MHz15 MHz25 MHz35 MHz

Försök 3 med Fit: 2003-10-02 15:50:26

r (mm)��������������

Am

plitu

de. (

a.u.

)

�

�

Viscous penetrationdepth as function of

overtone

radial amplitude distribution(normalized)

Instrument operation

driving freq ~10 ms decay recording ~2 ms data communication ~13ms

5Mhz 15Mhz 25Mhz 35Mhz 5Mhz

Crystal non-oscillating 50% of the time

time

Features•Sequential multi frequency measurement•Freely oscillating crystal=true crystal frequency •Enables multiple frequencies & viscoelastic modeling

The Q-Sense E4 System

•4 Sensors•Electrochemistry Module•Flow / stagnant mode•Wide range of chip coatings

www.q-sense.com

Removable flow module

Inlet

Outlet

Quartz crystal

Flow channels for temperature stabilization

Cross section of flow module

Example of Measurement Set Ups

1

2

3

4

paralell

1

2

2 by 2 parallel

1

serial

1

2

2 by 2 serial

Electrochemistry

New possibilities with Q-Sense E4

E-Chem moduleCounter electrode99.95% Pt

Reference electrodeAg/AgCl

Left or Right hand configuration1 or 2 modules can be used with one E4

Q-Sense D300 System

•1 sensor•Designed for batch mode measurement

Measurement chambersWindow ChamberQWiC 301

• simple design allowing easy adaptation:microscope, light radiation, living cells & bacteria …

• stagnant liquids

Axial Flow ChamberQAFC 302

• flowing liquids:batch & flow modes

• excellent signal stability

Common QCM-D ApplicationsSurface interaction•Biomolecules (protein, vitamin, antibody, DNA etc)•Polymers/polyelectrolytes•Particles•Cells

Surface reaction•Conformation change (protein, DNA, polymer, cells)•Crosslinking (protein, polymer etc)•Hydration (polymer)

H2O

Common application areas

Surface(QCM-D)

Drug development

Surfactants

Biomaterials

Drug discovery

Biofouling

Biosensors

Polymers

300 400 500 600 700time (s)

SiO2two steps to bilayer

26 Hz

-1

0

1

2

3

4

400 500 600 700 800

Dis

sipa

tion

(10-6

)

time (s)

-80

-60

-40

-20

0

freq

uenc

y (H

z)

gold with alkane thiolmonolayer adsorption

13 Hz

400 500 600 700 800time (s)

oxidized goldvesicle adsorption

90 Hz

C.A. Keller and B. Kasemo, Biophysical J. 75 (1998) 1397.

Lipid vesicleadsorption

Ø 25 nm

Summary Introduction

• Real Time Surface Sensitive Technique• Sauerbrey (Linear relation �f vs �m)

• Overtones (different sensitivity, modeling)

• Surface interaction/reaction

Thank you for your attention!