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Electrochemical sensing at Acreo - electrochemistry and impedance Anatol Krozer, Sensor Systems, Göteborg. Hudiksvall ( Optical fibers, R&D and production ). Kista, Stockholm ( Optical Fibers R&D, Nano, SiC ) …. Norrköping ( Printed electronics ). Göteborg, Sensor Systems.

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Electrochemicalsensing at Acreo- electrochemistry and impedanceAnatol Krozer, Sensor Systems, Göteborg

Hudiksvall (Optical fibers, R&D and production)

Kista, Stockholm (Optical Fibers R&D, Nano, SiC) …

Norrköping (Printedelectronics)

Göteborg,

Sensor Systems


Acreo sensor systems people involved
Acreo, Sensor Systems - peopleinvolved

Dag Ilver

Christer Johansson

Kristina Fogel

Jakob Blomgren

John Rösvall

Torbjörn

Pettersson

Fredrik Ahrentorp

AK

Andrea Astalan

Cristina Rusu

Boris Stoev

Lei Ye, Keichii Yoshimatsu, … - AppliedBiochemistry, Lund Univ

Kristina Reimhult, LuSun, …


Fluid response to variable voltage global vs local
Fluid responsetovariablevoltage - global vs local

VAC

  • Mobile ions/chargedparticles in a liquidacttoscreenaway an externalelectricfield→ charge separation → charge pile upclosetoelectrodes. At mostionicconcentrations of interest the electricfield, E, inside the liquid is ≈ 0 in equilibrium.

  • Typical screening distances at ionicstrengths of interesthereare < µm. The ion excess at electrodes (the double layer) inducescapacitances µF.

  • Ioniccurrent in a fluid, I, is given by: – concentration, – effectiveion charge and – ionmobility.

  • Variableexternalvoltage→ Iresponse lags behindVduetosizeeffects. Contributionduetoionic/particle motion decreaseswithfrequency.

IAC


Local at electrodes artificial biofilm self assembled ph sensitive peptide monolayer
Local (at electrodes): artificial biofilm – self assembled pH sensitive peptide monolayer

Designed, pH sensitive, thiol terminated peptides well known adsorption properties on the gold surface dense and insulating monolayer is formedC linear = CKHEYKHEYKHEYKHEYKEHEHEHH (-COOH)

E - Glutamicacid; C - Cystein; K - Lysine; H - Histidine; Y – Tyrosine

pH response

Peptidelayerthickness < 50nm

  • Thicknesschanges of fewnmcan be detected

  • Detection of small changes of ionconcentration

  • Quantitativedetection by data fitting


Global aging of lubricants for cutting tools at volvo sk vde plant

  • Two pH sensitive peptide monolayerapproaches:

  • plane electrodes: f < 1MHz

  • Planar coil: f  5MHz

Global: aging of lubricants for cuttingtoolsat Volvo Skövde plant

Addinglubricationoil

Lubricant

Planparallel electrodes Planar coil

Vinnova grant – waterqualitymonitoring ”Sensation”


Local biofouling c apacitive detection
Local pH sensitive peptide monolayer: Biofouling - capacitivedetection

Similar principle applies for planar electrodesfacingeachother (seepreviousslide), for the interdigitated finger configuration or for planar coils as shownhere.

Buffer

MIP

MIP

MIP

MIP

MIP

MIP

MIP

MIP

Passive polymer matrix

Passive polymer matrix

-

+

+

Si wafer/glas

+

-

Planar electrodes: Sensingdepth is of the order of electrode – electrodedistance.

Si wafer/glas

Example: Milk handling - biofilm


Molecularly imprinted polymers on microelectrodes

AFM pH sensitive peptide monolayer

Molecularlyimprinted polymers on microelectrodes

  • Polymers withmolecular ”memory” ”artificialantibodies”

  • Applicablemainlytomolecules < kDabutimprints of peptides, proteins and evenmicroorganismsare under development

  • Robust (shelflife – years)

  • Toxins, eg., marine toxins or volatile mouldproducts

  • Narcotics

  • Chemicalwarfare agents

  • Explosives

  • Peptides

  • Pharmaceuticalwaste

  • Tannins, coffeines

  • Sugars, (sorbitol, glucose)

170nm S-MIP in PET

2,4µm S-MIP particles in PET

SECURITY - Emergency Support System no: 217951


Zephyr measuring ion content and moisture of earth
Zephyr pH sensitive peptide monolayer - measuringioncontent and moisture of earth

Similarresults for fits with less datapoints

Water

supply

to PC

Resultscomparedwith the commerciallyavailable sensor

  • Drawbacks (lack of electronics for fieldconditions)

  • measuresonlyImpedanceamplitude! Phase info is lost (but Kramers-Krönig relations areoftenapplicable)

  • Measuresonly at descretenumber of frequencies (here at 2 frequencies)

  • →requires extensive calibrations & modelling

  • Electronics underway (see eg., http://sciospec.de/cms/home)

Grant ENV.2012.6.3-1: ZEPHYR no: 308313


Zephyr improved model for soil measurements
Zephyr pH sensitive peptide monolayer - Improvedmodel for soilmeasurements

Grant ENV.2012.6.3-1: ZEPHYR no: 308313


Coil as an electric component
Coil pH sensitive peptide monolayer as an electriccomponent

R=(R0 + 2p fL0’’)

L=L0 (1+ ’)

f < f0

Inductor

f << f0

resistor

f > f0

Capacitance

R

C

L

R0

Frequency

  • ’ and ’’ – in-phase and out-of-phase electric susceptibilities (polarisabilities) of the of the surrounding media

  •  is the coupling coefficient to the measured media (eddy currents)

  • Eddy currents (Garcia-Martin etal., Sensors (2011) vol. 11, pp. 2525-2565) → R  f2; L  f2

  • Typical skin depth is  0.2 m at 1 MHz and resistivity of 0.5 m (urine or physiological buffers) → in practice full penetration at most geometries

  • Impedance in liquids → substitute C by constant phase element, CPE 


Molecularly imprinted polymers mips

Use pH sensitive peptide monolayer of planar coilstofollow the kinetics of chemicalbinding (patent pending)

Molecularlyimprinted polymers - MIPs

Doseresponse – target: propranolol

Coilscoveredwith a dense ML of imprinted & non-imprintedbeadsusingmussel adhesive proteins as a ”glue” (patent pending)

Fit quality!

SECURITY - Emergency Support System no: 217951


Practical implementation battery powered autonomous system
Practical implementation – pH sensitive peptide monolayerbattery-poweredautonomous system

Temperaturestabilisation

MIP

NIP

Vac

R1

R2

-

+

Fully automatised and energizedWheatstone bridge configurationtodetectchanges of abs(ZMIP) – abs(ZNIP)

SECURITY - Emergency Support System no: 217951


Q [Asec/cm pH sensitive peptide monolayer2]

Molecular Imprinting of sugars (sorbitol)– cyclic voltammetry (CV)

Film preparation

  • Clean electrodes: H2O2/HNO3/H2O, UV-ozone & CV in 1M sulphuricacid

  • Polymerisation in 10 mMacetatewith monomer (54 ml 100 mg/ml) and 5 mMsorbitol

  • Deposit polymer by CV. Lowcurrentimplies the formation of a continuous MIP film.

Home-made electrochemical cell with an option for surface plasmon resonance detection

MIP performance by electrochemical impedance

The effect of Au cleannesson MIP deposition

MIP deposition

  • Film adhesion & MIP performance

  • Insufficient Au surface cleanness

  • Film stability

  • Poor sensitivity of impedance measurements → Use Imego designed microelectrodes

Q [Asec/cm2]

Anatol Krozer /20090121/


Integrated printed disposable biosensor acreo printed e lectronics
Integrated pH sensitive peptide monolayerprinteddisposable biosensor – Acreo PrintedElectronics

Amperometry, potentiometry or impedance

On-board signal processing

First demonstrator

Printed

biosensor

Printed

battery

Printed

circuitry

Printed

display

Chip

Final

goal

Current status

Demonstrated with glucose sensing


Acreo printed electronics manufacturing greenhouse
Acreo pH sensitive peptide monolayerPrinted Electronics – manufacturing greenhouse

  • 500 m2

    • 6 Printing machines screen, flexo, (2 R2R)

    • Equipment for test and inspection

    • Equipment for ink development

    • Offices

    • Meeting places

  • Manufacturing processes

    • 5 R2R single component processes

    • 4 sheet integrated systems processes

    • 1 R2R integrated system process (under development)

  • Activities

    • Prototype design

    • Product development

    • Production

    • Technology transfer

    • Workshops

Collaborationwith the Linköping University


The end
The end! pH sensitive peptide monolayer

  • Impedance is by far not the only area of ourinterest! Pleasecontactme for further information aboutourotheractivities. Theseinclude:

    • MEMS and their signal analysis - MEMS systems

    • Magnetism & magneticnanoparticles

    • Optical sensors – fluctuations, fluorescense, FRET, etc.

  • Weapplytheseto:

    • Inertialnavigation

    • e-health and e-sports

    • Immunoassayplatforms

    • Waterqualitymonitoring (rawwater, industrialwaste, urban water systems, etc.)

    • Bacteria detection and living sensors

    • Agriculture and cattle

    • Youname it!

  • Weaim at cheapbutfullyautomatized systems

  • Wegladlywelcomeindustrial and academiacont(R)acts and collaborations, and common fundingapplications!


Additional activities
Additional pH sensitive peptide monolayeractivities


Zephyr measuring ion and water content using wrapped coils
Zephyr pH sensitive peptide monolayermeasuringion and watercontentusingwrappedcoils

  • Bothinductance and capacitancechanges

  • It is possibletoextractconductivity ( ioncontent) and capacitance ( watercontent)

Grant ENV.2012.6.3-1: ZEPHYR no: 308313


Urea in tap water
Urea in pH sensitive peptide monolayertapwater

6

10

-2000

-27

5

10

|Z|

x104

4

-2

10

0

2,5

5

3

10

Z''

MQ 2

Tap water 2

-1000

-100

Tap water 1

MQ 3

Tap + 5% urea

-50

theta

0

-1

0

1

2

3

4

5

6

0

10

10

10

10

10

10

10

10

0

2000

4000

6000

8000

Frequency (Hz)

Z'

Requires Differential ImpedanceAnalysis


Our collaborators in bulgaria differential impedance analysis
Our pH sensitive peptide monolayercollaborators in Bulgaria – differential impedanceanalysis

  • Water-in-oil

  • Oilageing

  • Urea

  • Construction of a continuous, virtually care-free and self-calibrating equipment is possible

  • Although we presented data only up to 1 MHz we do have experience with experiments up to few tens of GHz. The latter may allow

    • remote sensing

    • ”chemical specificity”

  • Use of several narrow frequency measurement intervalls decreases equipment cost and enhances specificity

  • Software development and signal analysis are important


Waste from the waste treatment plant at bor s
Waste from the pH sensitive peptide monolayerwastetreatment plant at Borås

Beakerwith sedimented waste (after 0,5h) and electrodes


Monitoring fluid level
Monitoring pH sensitive peptide monolayer fluid level

Coil area: 50mm x 50mmMid openarea: 10mm x 10mmPitch = line width = 0,2mm

  • Probedepth≈width of the (pitch + current line)

  • Similarsensitivity for 3-dim coil and for coilswrappedaround the polymer chamber from the outside.

  • Resonancedamping (quality, Q-factor, decrease) depends on the ionicconcentration. For nakedcoil wires and ionicstrengthstypical of urine Q is low, Q  1

  • Dampingdecreasesconsiderablywhen the coil is covered by thinbutdenseinsulatinglayer


Coils
COILS pH sensitive peptide monolayer


Planparallella elektroder
Planparallella elektroder pH sensitive peptide monolayer

Två olika representationer av mätdata

8

Ny vätske”batch”

1

9

  • Slutsatser: det går att mäta något större (?) skillnader mellan de olika skärvätskorna även för den nya batchen jämfört med skillnadetr vid högre frekvenser

  • Modellering behövs


800 pH sensitive peptide monolayer

Conductivity ioncontent

600

100

Z'(Ohm @ 10 kHz)

400

80

200

60

Abs (Z) (Ohm)

Value

40

102

R

RC

3.1188e-8

Capacitans watercontent

20

a

0.99199

200

0

105

107

Capacitans (pF @ 3MHz)

f (Hz)

100

0

0

40

80

120

Watercontent (ml)


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