Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
e-mail: willnea@vms.huji.ac.il
URL: http://chem.ch.huji.ac.il/employee/willner/iwillner.htm
| Itamar Willner
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel e-mail: willnea@vms.huji.ac.il URL: http://chem.ch.huji.ac.il/employee/willner/iwillner.htm |
|
Electronic communication of biomaterials with electronic transducers is a fundamental challenge in the rapidly developing field of bioelectronics. Electrical contacting of redox-active enzymes, e.g. glucose oxidase, GOx, is accomplished by the surface-reconstitution of the apo-protein on a FAD-modified Au-nanoparticle on an electrode support. The enzyme-electrode exhibits unprecedented effective electrical communication with the electrode (electron transfer turnover rate 4500 s-1), leading to a very selective bioelectrocatalytic electrode. Electrically contacted GOx was also generated by the reconstitution of apo-GOx on a FAD-modified polyaniline associated with an electrode. By the modification of a micro element (cantilever) with the bioelectrocatalytic polymer film, the electrochemically driven mechanical deflection of the lever was accomplished due to the formation of surface-stress on the element. The surface-stress and the deflection of the cantilever are controlled by the concentration of glucose in the system, thus enabling the future development of a micro-insulin pump.
DNA-based bioelectronics is a rapidly progressing research field with potential applications in developing electronic DNA sensors, DNA-based electronic circuitry, and DNA computers. Bioelectronic DNA sensing will be exemplified with: (a) The surface replication of a target DNA with a redox-active replica of doxorubicin into double stranded DNA and the activation of the electrocatalyzed reduction of O2 to hydrogen peroxide and the subsequent biocatalyzed chemoluminescence.
Magnetic control of bioelectronic transformations has great future perspectives in bioelectronics. The functionalization of magnetic particles with electron-relay units allows the magnetoswitchable "ON" and "OFF" activation of bioelectrocatalytic transformations. By external magnetic rotation of the nanoparticles, bioelectrocatalyzed transformations are substantially enhanced due to the control of the reactions by convection rather than by diffusion. Accordingly, amplified detection of DNA or antigen/antibody was accomplished by the external rotation of the magnetic particles in different bioelectronic systems.
