Elektroanalytik & Sensorik • Elektroanalytik & Sensorik •

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

ano

de

catho

de

e-

e- e-

cellobiose dehydrogenase laccase

lactose

lactoso-lactone

e-

Os

Os OsOs

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-nano interactions.

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


8

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

-53 mV / pH unit

PHA - pyrene-hexanoic acid


16

Bioelectrocatalytic current forH2O2 reduction at +600 mV


17

Optimum pH

@ +400 mV vs. Ag/AgCl

Bioelectrocatalytic current forH2O2 reduction at +600 mV

PHA - pyrene-hexanoic acid


18

Hydrodynamic voltammogram

H202 oxidation

H202 reduction

at electrode

at HRP

High potential reduction of Cmp-I/II-HRP


19

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.


20

H2O2 biosensor at +400 mV@ no O2 involvement

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


21

HRP loading

Eappl=+300 mV

0 1 2 3 4 5 60

-200

-400

-600

-800I /

µA

[H2O

2] / mM

25 µg HRP

50 µg HRP

100 µg HRP

150 µg HRP

200 µg HRP

@ 1 cm-2


22

Is „glucose based cathode“ a promising candidate?

Biocathodes based on... Eonset pHopt

Cl- 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‘


23

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-)


24

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

• to ELANOS


25

for your attention!Thank you

Elektroanalytik & Sensorik • Elektroanalytik & Sensorik •

Documents

Transcript of Elektroanalytik & Sensorik • Elektroanalytik & Sensorik •