Researchers from Harvard have successfully created a transistor embedded in a v-shaped, lipid-coated nanowire that can penetrate a cell wall without compromising cell function. These virus sized bio-compatible transistors would allow for the manipulation and control of cells in ways that were once only a figment of the imagination. Individual cells could be signaled to create antibodies to fight pathogens or cancers. Cells could be probed to examine and observe their function in-vivo. Customized biomachines could be attached to living cells within a patients body to allow doctors to control or manipulate cellular processes. These transistors could even enable two-way communication with doctors and cells.
The transistor, an electrical switch, has an electric current source wire and a drain wire attached to either end of the transistor. These wires are necessary to allow for communication and control of the transistor. At such small scales, the digital processes and biological processes begin to lose distinction, making the two technologies relatively easy to integrate as long as the cell can be kept alive. This has proven difficult. In previous attempts at creating biocompatible transistors, the transistor wires would actually kill the cells once they pierced the cell walls.
To overcome this challenge, the Harvard researchers used a fatty lipid coating on the nanowires that mimics the lipids that are present in the cell wall. After this breakthrough, the transistors were actually accepted into the cells via cell membrane fusion. The cell essentially grew around the transistor, leaving the wire ends exposed. The exposed ends allow for larger mechanical devices to be attached to the cell and input signals directly to the organelles. Tests of the device indicate that it could be used not only to measure activity within neurons, heart cells, and muscle fibers, for example, but also to measure two distinct signals within a single cell simultaneously—perhaps even the workings of intracellular organelles, the functional units within cells that generate energy, fold proteins, process sugars, and perform other critical functions.
- . Label-free single-molecule detection of DNA-hybridization kinetics with a carbon nanotube field-effect transistor. Nature Nanotechnology [Internet]. 2011 ;6(2):126 - 132. Available from: http://engineering.columbia.edu/researchers-find-new-use-nanoscale-transistors
- Researchers Find New Use for Nanoscale Transistors. [Internet]. Submitted . Available from: http://engineering.columbia.edu/researchers-find-new-use-nanoscale-transistors
Bio-compatible nanoscale transistors can serve numerous functions including but not limited to: two-way communication with cells; attachment of biomechanical devices to live cells; monitoring of cellular functions in-vivo; and remote triggering of cellular functions.
The potential benefits of these transistors range from mundane and necessary treatments for heart disease and diabetes to exotic and designer therapies that improve the efficiency of intracellular processes. The potential limitations of this technology are more closely related to the ethical and moral implications they would have on society than the actual functionality of the transistors themselves. The concept and possibility of controlling our bodies at a cellular level will push the limits of what we perceive it means to be human. In theory, these types of control over the body's biological functions could create humans that have traits--advanced cognitive function, photosynthetic capability, enhanced energy conversion efficiency--that are the envy of science fiction writers and defense departments alike.
The risks associated with using bio-compatible nanoscale transistors are dependent on the application of the technology, but could potentially create risks to the human condition and human health should doctors or patients lose control of the transistors or their biomechanical devices (if the application includes them). Furthermore, the ecologcal risks of these devices is unknown should the devices be used in non-human cellular organisms to assert some form of control over the environment.