Posted: December 28, 2007

(Nanowerk News) Nanobioelectronics is a new, rapidly developing discipline, combining achievements of nanoelectronics and molecular biology. Science community has already developed theory and practical approaches to nanobioelectronics – DNA based nanocables, electronic sensors, storage devices and logical components. Basics of nanobioelectronics are processes of charge transport in biological macromolecules and applications of abovementioned molecules in building molecular structures of nanosize. Integration of nanoelectronic devices and such complex biological structures as cells throws a bridge between biotechnology and nanobioelectronics.

Size of biological materials, such as DNA (deoxyribonucleic acid), RNA (ribonucleic acid), proteins and biomembranes and etc, is comparable with sizes of nanotubes, nanoparticles and quantum dots. Combination of biomaterials with metal or semiconducting particles, fullerenes or carbon nanotubes results in a new class of materials for creating unique electronic or optical systems. Main trends of nanobioelectronics include creating hybrid biosensors, complex DNA-based nanoelectronic circuits, designing nanobiotransistors, diodes, nanoengines, nanotransporters and etc. Such devices require quantum-mechanical modeling and supercomputer calculations.

Nanotechnologies are a whole lot of technological approaches, which allow constructing nanosize objects, studying their properties and manipulating them. Nanoelectronics lies between most important branches of nanotechnology, using tiny nanoelements and even single molecules. Molecular-sized electronic devices and conductors allow building ultra-fast and ultra-compact computers with crucially new quantum algorithms. Today many researchers are inventing applications for fullerenes and nanotubes in nanoelectronics. Despite unique properties of carbon nanotubes, they are too expensive and not easy to control. DNA is an alternative material for creating nanowire, since in 1999 scientists discovered its ability to transport electrons along a polymer chain and to work as a conductor (Nature). However, reproducibility of experiments with DNA electron transport is not quite good, which is, most of all, due to significant changes in DNA’s native structure, taking place during its transfer to solid substrates from a solution.

Russian think-tank suggests the following: plasma-chemical surface modification allows reducing substrate effect on structure of absorbed DNA molecules and holding their “native” state, as well as showing great conductivity. Russian researchers together with their French colleagues showed DNA having superconductive properties in Science in 2001. Well-known goal of molecular nanoelectronics is creating a molecular computer with extremely high density of unit layout – about 1 billion per one square cm. Such high layout density requires ultra-low power dissipation on each working unit. Scientists consider only superconducting units to meet abovementioned requirements. In order to construct molecular electronic units engineers need to learn how to “manipulate” molecules, placing necessarily orientated units in a required position on a substrate. For this purpose Russian biological chemists suggest controlled adsorption of biological polymers.

Most recent studies are aimed at developing nanostructures for exploring DNA conductive properties, developing surface modification techniques for successful immobilization of DNA on nanoelectrodes and studying structure and properties of absorbed DNA. This task also requires synthesizing DNA-like linear molecules, showing improved mechanical stability and resistibility to stress, caused by transferring molecules from water to solid substrates. Most perspective molecules for this purpose are long triplets and quadruplets, which are more rigid than DNA and can be easily synthesized by means of enzymes.