What would it mean if biological and non-biological systems were not just fully connectable but fully interchangeable? That’s one of the questions that nanotechnology poses for us. More than any other field of scientific inquiry, nanotechnology operates at the basic scales of biology. DNA, for example, has a rough width of 2.5 nm. Viruses are roughly 20 to 250 nm. A bacteria is roughly 1000 nm. So, nanotechnology spans from the scale of individual biological molecules through the scale of simple biological systems to the scale of living cells.
The overlap between nanotechnology and biology has created two foundational revolutions in biology. The first is in imaging. The tools of nanotechnology, like transmission electron microscopes, have allowed scientists to see the basic building blocks of biology. Consider, for example, images of H5N1 flu virus particles taken by the CDC using a transmission electron microscope and images of DNA made by an atomic force microscope by researchers at the University of Bristol. Similarly, new nanoscale microscopes have enabled scientists to create detailed pictures of parts of the brain, such as neurons and their parts, like the endoplasmic reticulum.
The second major advance enabled by nanotechnology is the design of bio-electronic and bio-mechanical interfaces. For example, researchers at the University of Wisconsin-Madison have developed a new sensor for viruses that works through a combination of nanotechnology elements. The base of the sensor is a flat basin filled with liquid crystals (these are crystal molecules that behave like a liquid and form the core materials used in computer and flat-screen TVs). Within the basin are a series of parallel ridges approximately 5 nm on each side. These ridges help orient the liquid crystals so that they line up in parallel to the ridges and therefore exhibit a constant color across the entire basin. Finally, set into the ridges are a series of antibody particles for a specific virus. Once built, the sensor is exposed to material that might contain the virus in question. If the virus is present, it will bind to the antibody and, when it does, disturb the arrangement of the liquid crystals. When the liquid crystals are disturbed, the sensor changes color, signaling a positive match.
Other examples came out of a recent study we conducted at the Center for Nanotechnology in Society that involved brain-machine interfaces. Most current brain-machine interface technologies operate at a pretty broad scale, involving an electrode that connects to hundreds or thousands of neurons at a time. Nanotechnology is already pushing the technological envelope in this area in several ways. One is involved in trying to create nanoscale structures on the surface of the electrode that improve its functionality, e.g., by reducing the likelihood that infections will develop at the interface or by promoting greater electrical conductivity between the electrode and the neurons. Another approach is to design much smaller arrays of electrodes that interact with individual neurons or even enable electrical conductivity between different parts of a single neuron.
Taken together, it seems clear that the nano-bio interface is already becoming a major new domain of scientific research and will lead in the future to new devices and techniques that integrate biological, electrical, and mechanical systems in much greater depth and sophistication. This, in turn, will challenge society to think hard about how far it wants to go in integrating engineering and nature, including, perhaps especially, the integration of humans and machines.