Research Activities

The research of the group is focused on fundamental studies of electron transfer reactions and interfacial properties of nucleic acids and enzymes and on the development of advanced technologies for biosensors and biofuel cells.

Main Research Directions

- Sustainable Energy Production: Biofuel Cells and Photoelectrocatalysis

- Electrochemical Biosensors for Food Industry, Medicine, and Neuroscience Research

- Fundamental studies of Electron Transfer Reactions in Biological Systems: Electron transfer in DNA and proteins and Bioelectrocatalysis

- Nanoelectrochemical applications 

Electrochemical studies of bacterial and plant hemoglobins and flavohemoglobins

Bacterial and plant hemoglobins and flavohemoglobins are involved in cellular protection against stress and reactive environmental changes and are excellent electrocatalytic systems for the development of artificial bioelectronic and biosensor systems, simulating the natural ones and successfully operating in vitro.

Electrochemical studies of bacterial and plant hemoglobins

Redox reactions of truncated hemoglobin from Bacillus subtilis (trHb-Bs) may be related to its very special in vivo signaling functions. Electron transfer (ET) in trHb-Bs covalently attached via its surface amino acid residues either to COOH- or NH2-terminated (CH2)2-16 alkanethiol SAM on gold were shown to depend on the alkanethiol length and functionalization, being limited not by electron tunnelling through the SAMs but gated by ET preceding reactions such as conformational changes in the heme active site/at the interface. This is a pioneer electrochemical work on biological ET sensor-and-actuator systems, shedding some light on the complex mechanisms by which organisms may receive information on environmental changes and adaptively respond to it.

Electrochemical interconversion of NAD+/NADH by E. coli flavohemoglobin (HMP)

Electrocatalytic recycling of the biotechnologically important NADH/NAD+ couple, a soluble electron accepting cofactor of more than 400 NAD(P)+-dependent dehydrogenases, is a true challenge in industrial biosynthesis and biosensor and biofuel cell development. E.coli HMP oriented at electrodes via amphiphilic promoter can electrochemically catalyse interconversion of NADH and NAD+ at potentials of HMP’s heme (the patent application filed). Heme serves as an electron transfer relay between the electrode and the FAD site of HMP, where the redox transformation of NADH/NAD+ occurred. Bioelectrocatalysis of NADH oxidation by HMP is improved compared to existing bioelectrocatalytic systems, which makes HMP very attractive as a component of bioanalytical and bioenergetic devices that require NAD+/NADH recycling.

Design of Bioelectronic Interfaces

Activation of electron transfer (ET) in proteins by dendrimer and nanoparticle relays

Robust molecular bioelectronic devices require a programmable electronic communication between proteins and electrodes. In one approach, protein reconstitution onto their cofactors wired to electrodes enables fixation of the proteins at different ET lengths and in strictly anisotropic orientations. Horseradish peroxidase (HRP) reconstituted on the heme cofactor conjugated to the alkanethiol linker and tethered to gold electrodes exhibits fast ET further enhanced by the gold nanoparticle relay. In another approach, wiring of enzymes to electrodes is performed by redox-labelled 3G dendrimers, providing dendrimer-templated space separation of proteins and their wiring to electrodes. Both results allow the molecularly-controllable design of bioelectronics interfaces.

DNA-templated bioelectronics interfaces

ChemComm 

We have demonstrated for the first time the electrochemical read-out of the nanomechanics of DNA origami where a pH-induced nanomechanical switching of i-motif structures incorporated into DNA origami bound onto cysteamine-modified basal plane HOPG was electronically addressed. This paves the way for construction of electrode-integrated bioelectronic nanodevices exploiting DNA origami patterns on conductive supports.

 

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Sustainable Energy Production

Photoelectrocatalytic Oxidation of Water by Hematite Electrodeposited on FTO

Zn/Ti-modified nanostructured hematite photoanode electrodeposited on FTO shows improved efficiency and decreased overpotential of photoelectrocatalytic oxidation of water. The improved performance of modified hematite is due to the combination of the enhanced electrical conductivity and facilitated charge transport in the bulk phase and at the electrode surface. The effect of Zn, decreasing the overpotential of the reaction by 218 mV, correlates with Zn contribution to interfacial catalysis. Current research is focused on further developments of modified hematite photoanodes operating under ambient environmental conditions and moderate potentials.

 

Biofuel Cells and Photoelectrocatalysis

The research is focused on the development of sustainable, commercially relevant and practically useful biofuel cells, exploiting enzymes as catalysts of raw materials transformation and nanoelectrocatalysis. Such power devices can be used for a number of special applications, such as disposable implantable power suppliers for medical sensor-transmitters and drug delivery/activator systems and self-powered enzyme-based biosensors. Our current research is focused on biofuel cells operating in whole blood and under air-breathing conditions.

biobattery

Examples of our hybrid biofuel cells based on laccase oxygen biocathodes and a Zn battery-type anode:

  1. Reconstitution of Peroxidase onto Hemin-Terminated Alkanethiol Self-Assembled Monolayers on Gold, Sosna, M., Fapyane, D., Ferapontova, E.E.* J. Electroanal. Chem. 728 2014 18-25.
  2. Lörcher, S., Lopes, P., Kartashov, A., Ferapontova, E.E.* Direct bioelectrocatalysis of O2 reduction by Streptomyces coelicolor laccase orientated at promoter-modified graphite electrodes, ChemPhysChem 2013 in press

Electrochemical Biosensors for Food Industry, Medicine, and Neuroscience Research

We develop technologically relevant enzymatic biosensors for food industry and medicine, which are represented by biosensors for theophylline, hydrogen peroxide, sulphite, glucose, amino acids and superoxide species. Current research involves the development of enzymatic biosensors for glucose, cholesterol, neurotransmitters and greenhouse gases, and DNA- and aptamer-based biosensors for neurotransmitters, cancer diagnosis, antibiotics, mycotoxins and bacteria.

Enzyme Biosensors

p-biosens

Some examples of our biosensors for bacteria and NADH:

  1. Sosna, M., Bonamore A., Gorton L., Boffi A., Ferapontova, E.E.* Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphite electrodes, Biosens. Bioelectron. 42 2013, 219-224, dx.doi.org/10.1016/j.bios.2012.10.094).
  2. Shipovskov S., Saunders A.M., Nielsen J.S., Hansen M.N., Gothelf K.V., and Ferapontova E.E.*, Electrochemical sandwich assay for attomole analysis of DNA and RNA from beer spoilage bacteria Lactobacillus brevis, Biosens. Bioelectron. 37 2012, 99-106, also www.rsc.org/Publishing/Journals/CC/article.asp

 

Biosensor for cancer diagnosis

The research is focused on the development of a new generation of electrochemical nanobiosensor platforms for rapid, sensitive and selective molecular diagnostics of cancer and bacterial and viral infections.

 dna-biosens 

  1. Farjami E., Clima L., Gothelf K.V. and Ferapontova E.E.* An “off-on” electrochemical hairpin DNA-based genosensor for cancer diagnostics, Anal. Chem., 83(5) 2011, 1594-1602
  2. Abi A., Ferapontova, E.E.* Electroanalysis of single nucleotide polymorphism by hairpin DNA architectures, Anal. Bioanal. Chem. 2013 DOI: 10.1007/s00216-012-6633-z

 

Biosensors for neurotransmitters and neurodegenerative diseases

The research involves development of electrochemical aptamer based nanosensors for selective and real-time in vivo analysis of neurotransmitters in brain and biosensor platforms for drug screening and reliable analysis of protein biomarkers of such neurodegenerative diseases as  Parkinson’s and Alzheimer’s disease, schizophrenia, psychosis and drug addiction.

aptamer

Some examples of our biosensors for neurotransmitters:

  1. Farjami, E., Campos, R., Nielsen, J., Gothelf, K., Kjems, J., Ferapontova, E.E.* RNA aptamer-based electrochemical biosensor for selective and label-free analysis of dopamine, Anal. Chem. 85 2013, 121-128, DOI:10.1021/ac302134s.
  2. Ferapontova E. E.*, Olsen E.M., Gothelf K.V.* An RNA aptamer-based electrochemical biosensor for detection of theophylline in serum, J. Am. Chem. Soc. 130(13) 2008, 4256-4258

 

Fundamental studies of Electron Transfer Reactions in Biological Systems: Electron transfer in DNA and proteins and Bioelectrocatalysis

The research is focused on the mechanisms of ET in DNA, proteins and enzymes, for further application of this knowledge in nanometre scale bioelectronic devices and biosensors.

 

Electron transfer in proteins

Our electrochemical studies show that long-range electron transfer in redox proteins anisotropically orientated onto electrodes occurs via specific existing electron transfer pathways within the protein structure. Our current research is focused on the ways the most efficient electron transfer reactions in enzymes may be modulated by proper enzyme orientation at the electrodes or by reconstitution of proteins onto the chemically modified electrode surface.

hrp

 

Electron transfer in DNA

Electron transfer in DNA duplexes tethered to the electrode surface is shown to depend on such factors as potential-induced electric field, charge of the redox probe, the way the redox probe is attached to the DNA, and the presence of electron transfer mediators. Only for the intercalated redox probes electron transfer is mediated by the DNA duplex. Our work is focused on different ways the electron transfer between the redox probes and the electrode may be modulated and on analysis of the electron transfer mechanisms.

dna-et

  1. Abi, A., Ferapontova, E.E.* Unmediated by DNA electron transfer in redox-labeled DNA duplexes end-tethered to gold electrodes, J. Am. Chem. Soc. 134 2012, 14499–14507
  2. Farjami E., Campos, R., and Ferapontova E.E.* Effect of the DNA end of tethering to electrodes on electron transfer in methylene blue-labeled DNA duplexes, Langmuir 28 2012, 16218-16226.
  3. Kartashov A.V., Serafini G., Dong M., Shipovskov S., Gazaryan I., Besenbacher F. and Ferapontova E.E.* Long-range electron transfer in recombinant peroxidases anisotropically orientated on gold electrodes, Phys. Chem. Chem. Phys., 12 2010 10098-10107, www.rsc.org/publishing/journals/CP/article.asp