NANOSTRUCTURED BIOELECTRONIC INTERFACES

• Sponsoring Institution: State Agricultural Experiment Station
• Project Status: COMPLETE
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 0212690
• Project Start Date: Oct 1, 2007
• Project End Date: Sep 30, 2012
• Program Code: [(N/A)]- (N/A)

Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824

Performing Department
CHEMICAL ENGINEERING

Non Technical Summary
Redox enzymes carry out oxidation and reduction reactions that can convert biobased raw materials into high-value products. Industrial application of redox enzymes is limited by factors including (1) low enzyme stability outside of a limited range of temperature and pH, (2) high cost of producing and purifying the enzymes, and (3) inefficient coupling of the enzymes to electrodes and other molecules that participate in the reaction (e.g., cofactors). This project is designed to address these limitations. Highly stable redox enzymes will be produced using DNA isolated from microbes that grow at high temperature. These enzymes will be used to produce novel interfaces that provide efficient electrical communication between the redox enzymes, electrodes, cofactors, and other molecules. The resulting bioelectronic interfaces will be used in novel biosensors and electrochemical bioreactors that produce high-value products.

Animal Health Component

40%

Research Effort Categories

Basic

60%

Applied

40%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
402	7299	1000	10%
402	7299	2020	10%
404	7299	1000	10%
404	7299	2020	10%
501	7299	1000	10%
501	7299	2020	10%
511	7299	1000	10%
511	7299	2020	10%
711	7299	1000	10%
711	7299	2020	10%

Knowledge Area
511 - New and Improved Non-Food Products and Processes; 711 - Ensure Food Products Free of Harmful Chemicals, Including Residues from Agricultural and Other Sources; 501 - New and Improved Food Processing Technologies; 404 - Instrumentation and Control Systems; 402 - Engineering Systems and Equipment;

Subject Of Investigation
7299 - Research equipment and methods, general/other;

Field Of Science
2020 - Engineering; 1000 - Biochemistry and biophysics;

Keywords

bioelectronic

dehydrogenase

biocatalysis

biosensor

mediator

bioreactor

biological fuel cell;

Goals / Objectives
The objectives of this project are (1) to develop nanostructured bioelectronic interfaces that achieve efficient electron transfer between a carbon electrode, an electron mediator, a cofactor, and a thermostable dehydrogenase; (2) to analyze the simultaneous mass-transfer, electron transfer, and reaction kinetics that govern the reaction rate; and (3) to develop predictive mathematical models to design and optimize electrodes for bioelectrocatalysis.

Project Methods
Dehydrogenase enzymes catalyze oxidation/reduction reactions involving transfer of two electrons between the substrate and an electron-carrying cofactor. This proposal seeks to create economical dehydrogenase-based electrodes for bioelectrocatalysis. The diversity and specificity of dehydrogenases found in nature offers the potential to produce a wide range of biosensors, food components, and biobased chemicals, including chiral sugars, amino acids, alcohols, and steroids, and pharmaceutical intermediates. The outstanding commercial potential of dehydrogenase-based bioelectrocatalysis has not yet been realized, though, due to high enzyme and cofactor costs and low volumetric reaction rates. This project will elucidate the complex interactions between mass transfer, electron transfer, and reversible enzyme kinetics that govern the performance of bioelectronic interfaces based on dehydrogenases, the largest class of oxidoreductase enzymes. Thermophilic enzymes will be used to enhance the interface's lifetime, catalytic performance, and activity range. Novel interface architectures will be developed that give efficient multi-step electron transfer between carbon electrodes and tethered mediators, cofactors, and dehydrogenases. The limits of high-surface area electrodes as a route to industrial-scale turnover rates will be explored. The results of these studies will have broad impact on the ability of US industries to produce high-value biobased foods and chemicals. Research results will be disseminated via conference presentations, peer-reviewed publications, and a project website.

Progress 10/01/07 to 09/30/12

Outputs
OUTPUTS: Results of this study have been disseminated in several ways. They have been published in peer reviewed publications, and they have been presented at professional conferences. In addition, results were presented at the annual meeting of the Hatch Multistate Research Project, "The Science and Engineering of a Biobased Industry and Economy." PARTICIPANTS: Robert Mark Worden (principal investigator) TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This research has produced a change in knowledge, which resulted in several publications. In the paper by Lu et al., (2008) entitled, "Nanometal-Decorated Exfoliated Graphite Nanoplatelet Based Glucose Biosensors with High Sensitivity and Fast Response." The significance of this work is shown by the article's being highlighted in Nanowerk Spotlight, posted September 8, 2008 (http://www.nanowerk.com/spotlight/spotid=7144.php). The following excerpt is from that Nanowerk news article: "Carbon nanomaterials have been extensively used in electroanalysis... To detect biologically derived electronic signals, CNTs are often functionalized with linkers such as proteins and peptides to interface with soluble biologically relevant. Now, for the first time, scientists have tested nanometal decorated graphene (actually graphite nanoplatelets, a thickness of 10 nm would contain approximately 30 graphene sheets, considering an interlayer spacing of 0.335 nm) in biosensor application. As it turned out, this novel biosensor is among the best reported to date in both sensing performance and production cost." In the paper by Hassler et al., (2008) entitled, "Versatile bioelectronic interfaces on flexible non-conductive substrates," novel, nanostructured bioelectronic interfaces were developed that have application for biosensors and biocatalysts. The approach uses a new bench-top method to form bioelectronic interfaces containing a gold film, electron mediator, cofactor, and dehydrogenase enzyme (secondary alcohol dehydrogenase and sorbitol dehydrogenase) on nonconductive substrates such as polystyrene and glass. The method combines layer-by-layer deposition of polyelectrolytes, electroless metal deposition, and directed molecular self-assembly. Cyclic voltammetry, chronoamperometry, field emission x-ray dispersive spectroscopy, scanning electron microscopy, and atomic force microscopy were used to characterize the bioelectronic interfaces. Interfaces formed on flexible polystyrene slides were shown to retain their activity after bending to a radius of curvature of 18 mm, confirming that the approach can be applied on cheap and flexible substrates. The remaining two papers by Jadhav et. al (2008) describe development of novel nanostructured biomimetic interfaces suitable for membrane proteins. These interfaces could have utility to biocatalysis involving membrane-bound enzymes.

Publications

• Lu, J.; Do, I.; Drzal, L. T.; Worden, R. M.; Lee, I. (2008) "Nanometal-Decorated Exfoliated Graphite Nanoplatelet Based Glucose Biosensors with High Sensitivity and Fast Response," ACS Nano, published online (DOI :10.1021/nn800244k).
• Hassler, B. L.; Amundsen, T. J.; Zeikus, J. G.; Lee, I.; Worden, R. M., (2008), "Versatile bioelectronic interfaces on flexible non-conductive substrates," Biosensors & Bioelectronics 23(10), 1481-1487.
• Jadhav, Sachin R., Zheng, Yi, Garavito, R. Michael, and Worden, R. Mark (2008) "Functional Characterization of PorB class II Porin from Neisseria meningitidis using Tethered Bilayer Lipid Membrane." Biosensors and Bioelectronics, published online (DOI:10.1016/j.bios.2008.07.010)
• Jadhav, S. R.; Sui, D. X.; Garavito, R. M.; Worden, R. M. (2008). "Fabrication of highly insulating tethered bilayer lipid membrane using yeast cell membrane fractions for measuring ion channel activity," Journal of Colloid and Interface Science 322(2), 465-472.