Perspective pentru un nou biocatod de potenţial ridicat ...[H2O2]-1 (mM-1) Amperometric responses...

Analytische Chemie – Elektroanalytik & Sensorik RUHR-UNIVERSITÄT BOCHUM

1

Perspective pentru un nou biocatod de

potenţial ridicat – noi proprietăţi ale

enzimelor redox imobilizate pe nanostructuri

compozite de grafit-

Wenzhi Jia, Yvonne Ackermann, Wolfgang Schuhmann,

Leonard Stoica

Anal. Chem. - Elektroanalytik & Sensorik (ELAN)Universitätsstr. 150, Bochum 44780

Ruhr-University BochumGermany


Concept of bienzymatic membrane-less biofuel cell (BFC)

laccase

cellobiose dehydrogenase (CDH) Potential [mV] vs. Ag/AgCl 3M KCl

- ++150 -41 +450 +530

Ecell = 300

an

od

e

cath

od

e

e-

e- e-

cellobiose

dehydrogenase laccase

lactose

lactoso-

lactone

e-

Os

Os Os

Os

OsOs

Os

Os

Os

Os

Os

loading

H2O

O2

Stoica L. et al, Fuel Cells (2009), 9 (1), 53-62


3

Motivation for new material electrode

• High catalytic coverage:

– large amount of active enzyme;

• Large active area of electrode:– using hierarchical carboneous materials two-

generations CNT‘s

• Exploring specific properties of bio-nanointeractions.

Pout=E x I

[E]; A; kcat, n

E0‘


I. Large active area electrode

4


5

Graphite electrode surface


6

Composite material:CNT/CMF onto carbon paper

Preparation:

N. Li, X. Chen, L. Stoica, W. Xia, J. Qian, J. Aßmann, W. Schuhmann, M. Muhler

Adv. Mater. (2007), 19, 2957-2960


7

EIS characterisation of CNT/CMF

Properties:

•Low ohmic resistance => no potential loss;

•Ratio active/geometric area=200;

•Non-restrictive diffusion of enzyme substrate.

N. Li, X. Chen, L. Stoica, W. Xia, J. Qian, J. Aßmann, W. Schuhmann, M. Muhler

Adv. Mater. (2007), 19, 2957-2960


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Various supports


9


II. Exploring specific bio-nano interactions

10


11

250 results

HRP-CNT

Y. Yan et al., Langmuir 2005, 21, 6560-6566

...only at low potentials!!


13

Thermodynamic potential for

reduction = +750 mV


14

Any

specific bioelectrochemistry of HRP

@ these new materials?


15

Bioelectrochemistry of HRP-heme

-300 -200 -100 0 100 200 300-200

-150

-100

-50

0

50

100

150

I /

µA

Eappl

/ mV

pH 5

pH 6

pH 7

pH 8

4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5

-100

-50

0

50

Pe

ak

Po

ten

tia

l (m

V)

pH

-53 mV / pH unit

PHA - pyrene-hexanoic acid


16

Bioelectrocatalytic current forH2O2 reduction at +600 mV

-200 0 200 400 600-250

-125

0

125

250

I /

µA

Eappl

/ mV

no H2O

2

1 mM H2O

2

-200 0 200 400 600

-100

0

100

200

I /

µA

Eappl

/ mV

no H2O

2

1 mM H2O

2


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Optimum pH

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8

-0.2

-0.1

0.0

0.1

0.2

Cu

rre

nt (m

A)

Potential (V)

HRP/PHA/CNTs/CF/GR in PBS

HRP/PHA/CNTs/CF/GR in 0.33mM H2O2

HRP/PHA/CNTs/CF/GR in 1mM H2O2

5 6 7 8

-0,05

-0,04

-0,03

-0,02

Cu

rre

nt (m

A)

pH

@ +400 mV vs. Ag/AgCl

Bioelectrocatalytic current forH2O2 reduction at +600 mV

PHA - pyrene-hexanoic acid


18

Hydrodynamic voltammogram

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8

-100

-80

-60

-40

-20

0

20

40

Cu

rre

nt (µ

A)

Potential (V)

H202 oxidation

H202 reduction

at electrode

at HRP

High potential reduction

of Cmp-I/II-HRP


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Scheme of H2O2 involvement

H2O2

H2O HRPox

HRPred

Biocathode@ +600 mV

1e-

+

1e-

W. Jia, S. Schwamborn, C. Jin, W. Xia, M. Muhler, W. Schuhmann, L. Stoica PCCP 12 (2010) 10088.


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H2O2 biosensor at +400 mV@ no O2 involvement

0 200 400 600 800 1000 1200-250

-200

-150

-100

-50

0

50

Time / s

I / µ

A

0 10 20 30 40 50

0

10

20

30

40

50

60

70

80

imax=0.22mA

kmapp=0.32mM

Cu

rre

nt-1

(m

A-1)

[H2O2]-1 (mM

-1)

Amperometric responses of the HRP/PHA-CNTs/CF/GR biosensor were recorded by

additions of H2O2 in N2-saturated PBS (pH 7.0) at +400 mV

Imax= 220 µA (~ 1.5 mM H2O2) KM= 320 µM H2O2

0 500 1000 1500 2000

50

100

150

200

[H2O

2] / mM

I red / µ

A


21

HRP loading

Eappl=+300 mV

0 1 2 3 4 5 60

-200

-400

-600

-800I

/ µ

A

[H2O

2] / mM

25 µg HRP

50 µg HRP

100 µg HRP

150 µg HRP

200 µg HRP

@ 1 cm-2


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Is „glucose based cathode“ a promising candidate?

Biocathodes based on...

Eonset pHoptCl-

inhibition

e- / O2

yield

Laccase +650 4 YES 4 e-

Bilirubin oxidase

+200 6-7 NO 4 e-

Glucose/HRP +600 7 NO 2 e-

Pout=E x I [E]; A; kcat, n E0‘


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Conclusions

3D-hierachical carbon nanostructures:– present excellent characteristics for large active area

and enhanced/”novel” bioelectrocatalysis of known redox enzymes;

Biocathode enzyme:– Yes, indeed, high potential biocathode functioning on

glucose/oxygen is feasible at in-vivo conditions (pH, Cl-)


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Acknowledgements go to...

• EU-FP7 funds (project no. FP7-NMP-2008-SMALL-2 )

• to ELANOS


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for your attention!

Thank you

Perspective pentru un nou biocatod de potenţial ridicat ...[H2O2]-1 (mM-1) Amperometric responses...

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