The understanding of double helix structure has brought revolution to the fields of molecular biology and genetics. The structural properties of DNA such as specific base pairing, a combination of stiffness and flexibility as well as remarkable stability (see Chapter 3) have made a huge impact in fields ranging from drug delivery to sensor design. With increased availability of chemically synthesised DNA strands and developments of super-resolution microscopy, DNA nanotechnology established itself as an independent area of research within bionanotechnology. DNA nanotechnology uses DNA as a versatile building block rather than a genetic code carrier. Although the genetic information of DNA was recognised soon after the discovery of the double helix in the 1950s, the potential of DNA assembly for the design of programmable structures was for the first time hinted in a theoretical paper written by Ned Seeman in 1982 (Seeman, 1982). His early theoretical work was followed by experimental studies that demonstrated the programmability of short DNA strands and their use for self-assembly of larger ordered structures.

Before we start looking into modification of nanomaterials and nanostructuring of biomolecular elements for various applications in biomedicine and material design, we need to get a glimpse into the structure of biomolecular building blocks and the way they interact and assemble.

In Chapter 6 we explored the field of DNA nanotechnology, and the use of nucleic acids to create programmable architectures on a nanoscale. In this chapter, we will look at other biomolecules and biological structures, which inspired the design of novel materials and devices. Although they can operate on a wide range of scales, going from nano to macro, all biosystems have one thing in common: they are the product of millions of years of evolution. They have been adapted to address a particular environmental challenge, such as the emergence of a new predator or the abundance of a particular nutrient or building block. For example, without an increase in the concentration of silicate and carbonate ions in water during the Cambrian period some 500 million years ago, there would have not been a dramatic increase in the number of marine creatures with silica and carbonate hard shells (Peters, 2012).

Nanomedicine, like conventional medicine, has two aims: to diagnose the disease, as accurately and as early as possible, and to deliver the most efficient treatment possible. Unlike conventional medicine, it uses nanomaterials and nanotools to achieve this. We saw in Chapter 8 the way in which nanotechnology advanced the field of biosensors, and we now look at some of the concepts behind the design of drug nanocarriers and nanocomposites for tissue engineering, as well as some challenges that still need to be overcome. In the core of bionanotechnology is the exploration of interactions between engineered nanomaterials with biomolecules and cells. Such studies are not only important to help the design of biocompatible materials, but also to assess the environmental impact of man-made nanosized structures. Nanotoxicology has emerged as an independent research discipline that studies the toxicology of nanostructures, which as we have seen in previous chapters have a unique set of properties due to their small size. Some of the protocols to assess the toxicological profile of new nanomaterials, as well as existing regulations and risk assessments, will be briefly covered in the last part of the chapter.

Characterisation of nanomaterials, whether this refers to their physicochemical properties or their interactions with biomolecules and cells, requires a combination of analytical strategies. Before we explore some of the main instrumental methodologies for analysis of bionano constructs and devices, it is important to define the main questions we are trying to answer using analytical techniques (Figure 5.1).

Bionanotechnology is an interdisciplinary field at the intersection of nanotechnology and biology. Whereas nanotechnology provides tools and platforms for exploration and transformation of biological systems, biology is a source of inspiration and building blocks, all with the aim to design new materials and devices.