Integration of photoswitchable materials and electronic transducer elements for optobioelectronic applications

Itamar Willner

Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel

 

Integrated systems consisting of photoswitchable biomaterials immobilized onto electronic transducers provide the basis for optobioelectronics.1,2 Biomaterial-based systems capable of recording and amplifying optical information, and electronic transduction of the stored information, can be envisaged. Alternatively, reversible biosensor devices or multi-component biosensor arrays can be tailored by controlling the functions of biomaterials by light.

Reversible, light-induced, activation or deactivation of the redox-functions of proteins, i.e. enzymes, that are associated with electrode supports, provide a general approach for the amperometric transduction of recorded photonic signals. Four different approaches to yield photoswitchable redox-activated electrodes will be addressed: (i) Immobilization of redox-enzymes modified by photoisomerizable units yield photoswitchable bioelectrocatalytic systems.3 (ii) Reconstitution of apo-flavo- enzymes with a semisynthetic photoisomerizable FAD cofactor and subsequent immobilization of the protein on the electrode supports, yields photoswitchable enzyme-electrodes.4 (iii) Control of the electrical contact of redox-proteins and the electrode support by means of a photoactive "command interface" associated with the electrode suppport.5 (iv) Application of photoisomerizable electron mediators that control the electrical contact between redox-enzymes and the electrode.6

Photoswitchable biological functions may also include the control of binding interactions.7 Photochemical switching of the binding interactions between an antibody and a photoisomerizable antigen layer associated with a solid support (transducer) will be described.8 The light-induced binding and dissociation of an antibody to and from the photoisomerizable antigen monolayer is transduced by electrochemical means, microgravimetric quartz-crystal-microbalance (QCM) experiments,9 and surface plasmon resonance (SPR) measurements.10 The photoswitchable formation and dissociation of antigen-antibody complexes enables the development of reversible immunosensors. Also, the specific interaction of antibodies with photoisomerizable antigens allows the patterning of surfaces with antibodies or antibody conjugates.11

 

1 (a) I. Willner and S. Rubin, Angew. Chem., Int. Ed. Engl., 35, 367-385 (1996).

(b) I. Willner and B. Willner, in Bioorganic Photochemistry, Vol. 2: Biological Applications of Photochemical Switches, H. Morrison (Ed.) Wiley, New York, 1-110 (1993).

2 I. Willner, Acc. Chem. Res., 30, 347-356 (1997).

3 (a) M. Lion-Dagan, E. Katz and I. Willner, J. Am. Chem. Soc., 116, 7913-7914 (1994).

(b) I. Willner, M. Lion-Dagan, S. Marx-Tibbon and E. Katz, J. Am. Chem. Soc., 117, 6581-6592 (1995).

4 (a) I. Willner, R. Blonder, E. Katz, A. Stocker and A.F. Bückmann, J. Am. Chem. Soc., 118, 5310-5311 (1996).

(b) R. Blonder, E. Katz, I. Willner, V. Wray and A.F. Bückmann, J. Am. Chem. Soc., 119, 11747-11757 (1997).

5 (a) M. Lion-Dagan, E. Katz and I. Willner, J. Chem. Soc., Chem. Commun., 2741-2742 (1994).

(b) I. Willner, A. Doron, E. Katz, S. Levi and A.J. Frank, Langmuir, 12, 946-954 (1996).

6 M. Lion-Dagan, S. Marx-Tibbon, E. Katz and I. Willner, Angew. Chem., Int. Ed. Engl., 34, 1604-1606 (1995).

7 (a) I. Willner, S. Rubin and Y. Cohen, J. Am. Chem. Soc., 115, 4937-4938 (1993).

(b) I. Willner, R. Blonder and A. Dagan, J. Am. Chem. Soc., 116, 3121-3122 (1994).

8 I. Willner, R. Blonder and A. Dagan, J. Am. Chem. Soc., 116, 9365-9366 (1994).

9 R. Blonder, S. Levi, G. Tao, I. Ben-Dov and I. Willner, J. Am. Chem. Soc., 119, 10467-10478 (1997).

10 E. Kaganer, R. Pogreb, D. Davidov and I. Willner, Langmuir, in press.

11 I. Willner and R. Blonder, Thin Solid Films, 266, 254-257 (1995).