Charles M. Lieber, PhD, (50) is the Mark Hyman Professor of Chemistry at Harvard University. His research focuses on the synthesis, fundamental physical properties, and applications of nano-scale materials with a focus on problems in the life sciences, nanoelectronic systems, and renewable energy. A recent recipient of the prestigious NIH Director’s Pioneer Award, Lieber is developing active interfaces between nanoelectronic devices, cells, and tissue. Lieber holds a PhD in chemistry from Stanford University.
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Where will the convergence of electronic devices and living cells take us?
Lieber: Nanowires offer an opportunity in that a cell will automatically internalize them. The idea is to build a communications bridge with cells or cell tissues that is indistinguishable from the biological system itself. This could open the door to monitoring cell activities and responses to medications in real time. A sensor package might, for instance, continuously monitor the blood for markers of anything from flu to cancer. And depending on the results, a device would automatically adjust the flow of a therapeutic substance to optimize treatment. We could do this for heart diseases or cancers by giving an atrisk individual a skin patch that would have a read-out and connection with a drug delivery system. That is the vision.
How are you realizing that vision?
Lieber: We have made nano structures out of semiconductor materials that can function as field effect transmitters (FETs) at the exact point of a kink in a wire (image left). Being like an arm, this allows the system to move in the 3D universe. A wire can thus enter a cell or touch a point on it such as a receptor or an ion channel. Our work in this area has, for the first time, made it possible to interrogate what is going on in a cell – without effect on a cell’s functions. This line of research could open a new world of knowledge.
For instance?
Lieber: If we can build arrays of these 3D systems, then we could make a tissue around them. This could be implanted in the brain or the heart to monitor and manage cellular processes in real time - a new kind of prosthetic device. This goes well beyond today’s state of the art, which is based on the use of huge - hundreds of microns - probes that cause scarring and degrade quickly. Unlike others in the microelectrode community (see Pictures of the Future, Spring, 2003, page 15), our lab has shown for the first time that one can interface on the sub-cellular level to cultured neurons.
Does this have implications for the field of nano-scale computing?
Lieber: You could develop a new kind of hybrid, living material - a living cell network that would be electronic and could itself be computationally active. So we have naturally asked ourselves if there is a convergence where molecules can bind to nano wires and thus produce the on-andoff messages needed for computing. The goal here is to combine the strengths of computers with human brain cells through nanoscale devices to make new types of computational systems with unique capabilities. It’s a hunch. But what I like to do as a scientist is to work on things that have not already been shown to work. I think there’s a world out there that will be enabled by the convergence of nano science and biology.
What applications do you foresee?
Lieber: Systems that function inside the body and that draw their energy directly from the mitochondria, for instance. This is something we are working on - in short, something like artificial tissue, but which draws power directly from the body.
Are there implications for environmental sensing, health and security?
Lieber: Yes, the problems are very similar between measuring cellular events within the body and interrogating organisms in the environment. For instance, variations of the same virus are distinguishable through slight differences in protein coatings, which are reflected in the virus’s binding properties and may, in turn, shed light on the organism’s level of threat.
What’s the timeline for some of the technologies we’ve been discussing?
Lieber: Sensor systems that can monitor hundreds of biomarkers for disease risks such as recurrence of cancer could approach introduction in five years. Prosthetic applications capable of creating an interface to the brain will start reaching the level of animal studies in about five years, with human applications in ten years.