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Enzyme-gelatin electrochemical biosensors: scaling down.

De Wael K, De Belder S, Pilehvar S, Van Steenberge G, Herrebout W, Heering HA - Biosensors (Basel) (2012)

Bottom Line: By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed.A full electrochemical study and characterization of the modified surfaces has been carried out.It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

View Article: PubMed Central - PubMed

Affiliation: Environmental Analysis, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium. Karolien.DeWael@ua.ac.be.

ABSTRACT
In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

No MeSH data available.


The current potential behaviour of a GelB/C (1), a drop dried HHC/GelB/C (2) and a spin coated HHC/GelB/C (3) electrode in a 10 mmol∙L−1 HEPES pH 7 buffer solution with a scan rate of 50 mV∙s−1.
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biosensors-02-00101-f001: The current potential behaviour of a GelB/C (1), a drop dried HHC/GelB/C (2) and a spin coated HHC/GelB/C (3) electrode in a 10 mmol∙L−1 HEPES pH 7 buffer solution with a scan rate of 50 mV∙s−1.

Mentions: Figure 1 shows the current-potential behavior of a drop dried (DD) GelB/GC electrode (1) and a DD HHC/GelB/GC electrode (2) in a 10 mmol∙L−1 HEPES pH 7 buffer solution in a potential window from −0.4 to 0.6 V with a scan rate of 50 mV∙s−1. No oxidation or reduction process is observed at a GelB/GC electrode. In this potential window, the gelatin matrix seems not to be electrochemically active at a glassy carbon electrode. When 0.5 mmol∙L−1 HHC is added to a GelB matrix, the corresponding current potential behavior is shown as curve 2 (which is the first scan obtained during the cyclic voltammetric experiment). The voltammogram shows a well-defined oxidation and reduction wave with peak potentials of 55 and −73 mV respectively, as expected for the oxidation and the reduction of the heme group present in the HHC protein [16,32,33]. The midpoint potential is 4 mV, consistent with the formal potential of HHC in solution [34]. In a previous article [16], the electrochemical behavior of a DD HHC/GelB/MH/Au electrode (MH = mercaptohexanol) was described. Similar diffusion controlled phenomena were observed. Within the thick DD gelatin layer, electron hopping between the biomolecules is responsible for the diffusion behavior [35].


Enzyme-gelatin electrochemical biosensors: scaling down.

De Wael K, De Belder S, Pilehvar S, Van Steenberge G, Herrebout W, Heering HA - Biosensors (Basel) (2012)

The current potential behaviour of a GelB/C (1), a drop dried HHC/GelB/C (2) and a spin coated HHC/GelB/C (3) electrode in a 10 mmol∙L−1 HEPES pH 7 buffer solution with a scan rate of 50 mV∙s−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263544&req=5

biosensors-02-00101-f001: The current potential behaviour of a GelB/C (1), a drop dried HHC/GelB/C (2) and a spin coated HHC/GelB/C (3) electrode in a 10 mmol∙L−1 HEPES pH 7 buffer solution with a scan rate of 50 mV∙s−1.
Mentions: Figure 1 shows the current-potential behavior of a drop dried (DD) GelB/GC electrode (1) and a DD HHC/GelB/GC electrode (2) in a 10 mmol∙L−1 HEPES pH 7 buffer solution in a potential window from −0.4 to 0.6 V with a scan rate of 50 mV∙s−1. No oxidation or reduction process is observed at a GelB/GC electrode. In this potential window, the gelatin matrix seems not to be electrochemically active at a glassy carbon electrode. When 0.5 mmol∙L−1 HHC is added to a GelB matrix, the corresponding current potential behavior is shown as curve 2 (which is the first scan obtained during the cyclic voltammetric experiment). The voltammogram shows a well-defined oxidation and reduction wave with peak potentials of 55 and −73 mV respectively, as expected for the oxidation and the reduction of the heme group present in the HHC protein [16,32,33]. The midpoint potential is 4 mV, consistent with the formal potential of HHC in solution [34]. In a previous article [16], the electrochemical behavior of a DD HHC/GelB/MH/Au electrode (MH = mercaptohexanol) was described. Similar diffusion controlled phenomena were observed. Within the thick DD gelatin layer, electron hopping between the biomolecules is responsible for the diffusion behavior [35].

Bottom Line: By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed.A full electrochemical study and characterization of the modified surfaces has been carried out.It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

View Article: PubMed Central - PubMed

Affiliation: Environmental Analysis, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium. Karolien.DeWael@ua.ac.be.

ABSTRACT
In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

No MeSH data available.