Bionanotechnology - Combining Nanotechnology with Biology

If we define nanotechnology as the application of materials and devices with characteristic (i.e. property determining) length scales between 1 and 100nm to the development of new products and processes; then bionanotechnology is its interface with biological systems.

Biology too has many examples of materials and structures that share a common length scale with nanotechnology, however it is the requirement for application that distinguishes bionanotechnology from biophysics or structural biology or virology. This is the same distinction that separates biotechnology from molecular and cell biology or physics from electronics and chemical engineering from chemistry.

Recognising that nanotechnology and biology share common length scales at this level we can see how the combination of the two creates the opportunity to produce and apply novel hybrid structures, materials and devices that exploit the distinctive features of both. Exploitation spans the use of nanomaterials as tools in fundamental biological research, the development of novel approaches to diagnose and treat disease as well as new ways to generate energy or clean up the environment.

The link between biology and nanotechnology is also seen in processes common to both domains such as self-assembly of the importance of kinetic rather than thermodynamic control in creating and maintaining structures. There are also significant differences between the two realms, perhaps most significantly the observation that many biological structures have only marginal stability at ambient temperatures with respect to non-functional states.

This can have important implications for building hybrid bionano constructs and it is in the design and fabrication of such "hard-soft" interfaces that bionanotechnology's distinctive flavour lies.

In bionanosensors we can see how biomolecules and nanomaterials can be combined to mutual advantage and produce devices with applications in clinical, environmental and bioprocess monitoring. The enhancement of bionanosensors compared to conventional biosensors arises from the fact that many nanomaterials have optical, electronic or magnetic properties that were unanticipated from knowledge of the bulk (macroscopic) material, largely as a consequence of the greater proportion of atoms in the former being at or near the surface.

Fabrication of particles, wires, pores, films or more complex structures with enhanced optical, electronic, magnetic or mechanical characteristics produce a new family of base sensors that lack only the molecular specificity necessary to use them in complex backgrounds. Of course it is such molecular recognition specificity that is the hallmark of biomolecules and the interface between the two is what provides bionanosensors with their analytical power.

As with conventional biosensors however, the native biomolecular properties are not always sufficient to provide an effective sensing interface as they have evolved to fit a specific biological role, not a sensing one.

If anything the situation is even more acute with bionanosensors as the high surface sensitivity of nanomaterials is best exploited when the biomolecule retains a high level of function. Molecular engineering can address this issue as well as others such as adjusting the dynamic range or enhancing stability.

In conclusion we can see therefore that bionanosensors put engineering at all length scales, from the molecular to the everyday at the heart of applying bionanotechnology in analytical science.