Bio-nano interactions: new tools, insights and impacts' gave concrete evidence that the newest phase is dawning in the nanotechnology era—the so-called fourth generation has arrived, illustrated by state-of-the-art examples, including self-assembly and bioelectronics for medicine.

The nanotechnology revolution offers new biomaterials, and better understanding and manipulation of bio-nano interactions of materials and cellular activity at the nanoscale, with fascinating opportunities for business and human health.

An added-value from study of nanotechnologies and nanomaterials is that these tiny materials allow scientists to probe cellular and tissue functioning and spotlight gaps in human knowledge. Indeed, several speakers highlighted the fact that getting very new ideas to a level of robust maturity in an emergent field can take years, especially when new knowledge and untested know-how challenge established norms in the medical field. For example, the validity of in vitro models and approaches, which have traditionally used 10% calf serum protein to sustain cell cultures, was questioned, because the introduction of nanomaterials results in binding of these proteins to the nanoparticle surfaces with the potential for presentation of a non-native biological identity due to unfolding of the proteins at the nanoparticle surface.

Across the wide range of topics discussed, the key underpinning concept (whether for discrete nanoparticles or nanostructured surfaces) was the role of nanomaterials as scaffolds for protein/biomolecule binding and the utilization of this for targeted therapeutic delivery, electrochemical sensing, control of stem-cell differentiation, as well as potentially as a basis for predicting nanoparticle fate, behaviour and safety.

Nanotoxicology represents a new and growing research area in toxicology. It deals with the assessment of the toxicological properties of nanoparticles (NPs) with the intention of determining whether (and to what extent) they pose an environmental or societal threat. Inherent properties of NPs (including size, shape, surface area, surface charge, crystal structure, coating, and solubility/dissolution) as well as environmental factors (such as temperature, pH, ionic strength, salinity, and organic matter) collectively influence NP behavior, fate and transport, and ultimately toxicity.

The mechanisms underlying the toxicity of nanomaterials (NMs) have recently been studied extensively. Reactive oxygen species (ROS) toxicity represents one such mechanism. An overproduction of ROS induces oxidative stress, resulting in inability of the cells to maintain normal physiological redox-regulated functions.

In the context of this book, this chapter includes topics pertaining to chemical and physical properties of NMs and characterization for proper toxicological evaluation, exposure, and environmental fate and transport, and ecological and genotoxic effects.