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Electrochemical sensing at Acreo - electrochemistry and impedance Anatol Krozer, Sensor Systems, Göteborg Kista, Stockholm (Optical Fibers R&D, Nano, SiC)

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Presentation on theme: "Electrochemical sensing at Acreo - electrochemistry and impedance Anatol Krozer, Sensor Systems, Göteborg Kista, Stockholm (Optical Fibers R&D, Nano, SiC)"— Presentation transcript:

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

2 Acreo, Sensor Systems - people involved Lei Ye, Keichii Yoshimatsu, … - Applied Biochemistry, Lund Univ Kristina Reimhult, Lu Sun, … Cristina Rusu Fredrik Ahrentorp Jakob Blomgren Christer Johansson Kristina Fogel Dag Ilver Andrea Astalan Torbjörn Pettersson Boris Stoev John Rösvall AK

3 Fluid response to variable voltage - global vs local V AC I AC

4 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 formed C linear = CKHEYKHEYKHEYKHEYKEHEHEHH (-COOH) E - Glutamic acid; C - Cystein; K - Lysine; H - Histidine; Y – Tyrosine Peptide layer thickness < 50nm Thickness changes of few nm can be detected Detection of small changes of ion concentration Quantitative detection by data fitting pH response

5 Global: aging of lubricants for cutting tools at Volvo Skövde plant Planparallel electrodesPlanar coil Adding lubrication oil Lubricant Two approaches: plane electrodes: f < 1MHz Planar coil: f  5MHz Vinnova grant – water quality monitoring ”Sensation”

6 Local: Biofouling - capacitive detection Similar principle applies for planar electrodes facing each other (see previous slide), for the interdigitated finger configuration or for planar coils as shown here. Planar electrodes: Sensing depth is of the order of electrode – electrode distance. MIP Passive polymer matrix MIP + Si wafer/glas + - Buffer MIP Passive polymer matrix MIP Si wafer/glas - + Example: Milk handling - biofilm

7 Molecularly imprinted polymers on microelectrodes -Polymers with molecular ”memory”  ”artificial antibodies” -Applicable mainly to molecules < kDa but imprints of peptides, proteins and even microorganisms are under development -Robust (shelf life – years) Toxins, eg., marine toxins or volatile mould products Narcotics Chemical warfare agents Explosives Peptides Pharmaceutical waste Tannins, coffeines Sugars, (sorbitol, glucose) AFM 170nm S-MIP in PET 2,4µm S-MIP particles in PET SECURITY - Emergency Support System n o :

8 to PC Water supply Zephyr - measuring ion content and moisture of earth Results compared with the commercially available sensor Drawbacks (lack of electronics for field conditions) measures only Impedance amplitude! Phase info is lost (but Kramers-Krönig relations are often applicable) Measures only at descrete number of frequencies (here at 2 frequencies) → requires extensive calibrations & modelling Electronics underway (see eg., Similar results for fits with less datapoints Grant ENV : ZEPHYR n o :

9 Zephyr - Improved model for soil measurements Grant ENV : ZEPHYR n o :

10 Coil as an electric component R L C Frequency R0R0 f < f 0 Inductor f > f 0 Capacitance f << f 0 resistor R= (R   fL 0  ’’) L=L 0 (1+  ’)

11 Molecularly imprinted polymers - MIPs Coils covered with a dense ML of imprinted & non-imprinted beads using mussel adhesive proteins as a ”glue” (patent pending) Dose response – target: propranolol Use of planar coils to follow the kinetics of chemical binding (patent pending) Fit quality! SECURITY - Emergency Support System n o :

12 Practical implementation – battery-powered autonomous system Temperature stabilisation SECURITY - Emergency Support System n o : Fully automatised and energized Wheatstone bridge configuration to detect changes of abs(Z MIP ) – abs(Z NIP ) MIP NIP R1 R2 V ac + -

13 Anatol Krozer / / Film adhesion & MIP performance Insufficient Au surface cleanness Film stability Poor sensitivity of impedance measurements → Use Imego designed microelectrodes Home-made electrochemical cell with an option for surface plasmon resonance detection Clean electrodes: H 2 O 2 /HNO 3 /H 2 O, UV-ozone & CV in 1M sulphuric acid Polymerisation in 10 mM acetate with monomer (54 ml 100 mg/ml) and 5 mM sorbitol Deposit polymer by CV. Low current implies the formation of a continuous MIP film. The effect of Au cleanness on MIP deposition Q [Asec/cm 2 ] Film preparation MIP performance by electrochemical impedance Molecular Imprinting of sugars (sorbitol) – cyclic voltammetry (CV) Q [Asec/cm 2 ] MIP deposition

14 Integrated printed disposable biosensor – Acreo Printed Electronics First demonstrator Current status Final goal Printed battery Chip Printed circuitry Printed display Printed biosensor Demonstrated with glucose sensing On-board signal processing Amperometry, potentiometry or impedance

15 Acreo Printed Electronics – manufacturing greenhouse 500 m 2 – 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 Collaboration with the Linköping University

16 The end! Impedance is by far not the only area of our interest! Please contact me for further information about our other activities. These include: – MEMS and their signal analysis - MEMS systems – Magnetism & magnetic nanoparticles – Optical sensors – fluctuations, fluorescense, FRET, etc. We apply these to: – Inertial navigation – e-health and e-sports – Immunoassay platforms – Water quality monitoring (raw water, industrial waste, urban water systems, etc.) – Bacteria detection and living sensors – Agriculture and cattle – You name it! We aim at cheap but fully automatized systems We gladly welcome industrial and academia cont(R)acts and collaborations, and common funding applications!

17

18 Additional activities

19 Zephyr measuring ion and water content using wrapped coils Grant ENV : ZEPHYR n o : Both inductance and capacitance changes It is possible to extract conductivity (  ion content) and capacitance (  water content)

20 Urea in tap water Z' Z'' 02, x10 4 Requires Differential Impedance Analysis

21 Our collaborators in Bulgaria – differential impedance analysis 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 Water-in-oil Oil ageing Urea

22 Waste from the waste treatment plant at Borås Beaker with sedimented waste (after 0,5h) and electrodes

23 Monitoring fluid level Coil area: 50mm x 50mm Mid open area: 10mm x 10mm Pitch = line width = 0,2mm Probe depth ≈ width of the (pitch + current line) Similar sensitivity for 3-dim coil and for coils wrapped around the polymer chamber from the outside. Resonance damping (quality, Q-factor, decrease) depends on the ionic concentration. For naked coil wires and ionic strengths typical of urine Q is low, Q  1 Damping decreases considerably when the coil is covered by thin but dense insulating layer

24 COILS

25 Planparallella elektroder Två olika representationer av mätdata Ny vätske”batch” 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

26 Conductivity  ion content kHz) Capacitans  water content Capacitans 3MHz) Water content (ml)


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