**2. DNA biomolecular electronics**

The role of ME is to provide reproducible well-structured architectures, easy to wire in a programmed manner. Supramolecular chemistry seems to fulfill these needs [22]. The two properties which are attractive for this purpose is the (a) molecular recognition and (b) selfassembly. Molecular recognition is the capability of a molecule to form selective bonds with other molecules or with substrates, which rest on the information stored in the structural features of the interacting partners. Molecular recognition processes (a) the building up of the devices from their components (b) incorporate them into supramolecular arrays; (c) allow selective operations on given species (e.g. ions, dopants), and (d) control the response to external perturbations (e.g. external fields, light, electrons, other molecules, etc.).

to understand whether DNA facilitates the charge transfer over long distances and whether the base pair stack can act as a conducting medium. The issue of charge migration in DNA has recently become a hot topic with solution chemistry (in particular) after the first reports by Jacqueline Barton's group [29–33] in the early '90s. Although the answer to the question: Is

Biomolecules and Pure Carbon Aggregates: An Application Towards "Green Electronics"

http://dx.doi.org/10.5772/intechopen.73177

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The recent achievement is the construction of few DNA-hybrid devices, which requires the application of some state-of-the-art nanotechnologies are: electron beam lithography for the fabrication of metallic nanocontacts, trapping techniques to compel the molecules into the desired device scheme, Atomic Force Microscopy (AFM) or Scanning Tunneling Microscopy

• Conversion of nucleic-acid (or DNA-protein) network into electron conducting system.

Though a lot of research conducting in this field is giving the contrasting results.

ent humidity, and different temperatures (from 1 to 300 K);

**5.** The presence of contacts and the effects of the DNA/electrode junction.

The DNA-based materials may be used either as conductive wires or as a template for other conductive materials. By exploiting the molecular recognition of its functional groups, it is possible to synthetize branched DNA-motifs that may be assembled into periodic arrays.

**1.** The intrinsic properties of the different DNA molecules employed in the experiments, the length of the DNA (from a few nanometers to some microns) and the structural conforma-

**2.** The properties of the buffer solution in which the DNA is kept and the presence and the

**3.** The experimental conditions in which measurements are realized: in air, in vacuum, differ-

Apart from experimental difficulties in the fabrication of DNA-based device, several fundamental questions are still open: what are the interactions which control the electrical properties of DNA? How do they depend upon the sequence? What are the mechanisms for charge transport? What are the effects of dopants or defects? How does DNA attach to a metal electrode? What are the effects of the contacts on the conduction properties of the

DNA can be used in various applications in green electronics, which is discussed herein.

**4.** The structural aggregation forms of DNA (films, network bundles, single molecules);

DNA a molecular wire? is still elusive.

(STM) for imaging and probing samples.

• Construction of nucleic-acid networks.

The most important ones are:

tion of the double helix.

device?

concentration of counter ions;

**2.2. Application of DNA in green electronics**

The achievement of DNA-based devices requires [33]:

The self-assembly has the capability of molecules to spontaneously organize in supramolecular aggregates under well-defined experimental conditions. Self-organization may occur both in solution and in the solid state, and make use of hydrogen bonding, electrostatic donoracceptor effects (Van der Waals, dipolar, etc.) or metal-ion coordination as basic interactions between the components. Due to these two properties, DNA molecules seem particularly suitable to be used as components for the construction of nanometer scale devices [23–26]. The idea of using DNA in molecular devices is its natural function of storing and coding the genetic information. DNA transmits well-defined chemical information through the pairing properties of the bases. In addition, it occurs in a large variety of structures and display physiochemical stability and mechanical rigidity.
