Mehmet Fatih Yanik, the Robert J. Shillman assistant professor of electrical engineering in EECS at MIT has discovered a way that will enable viewing a single live cell--without destroying the cell--the current outcome of using electron microscopes to see live tissue. Yanik and EECS graduate student William Putnam propose to overcome the harmful effects from direct scanning with electrons by using a quantum mechanical measurement technique that allows electrons to sense objects remotely.
As reported by the MIT News Office, October 6, 2009, such a non-invasive electron microscope could shed light on fundamental questions about life and matter--giving a glimpse at molecules as they carry out live functions within a living cell. This work has been reported by Yanik and Putnam in the October issue of Physical Review A -- Rapid Communications.
The significance for this possibility--if successful--would surmount what Nobel laureate Dennis Gabor concluded in 1956 was the fundamental limitation of electron microscopy: "the destruction of the object by the exploring agent."
In the proposed quantum mechanical setup, electrons would not directly strike the object being imaged. Instead, an electron would flow around one of two rings, arranged one above the other. Electrons will be able to hop between these rings--except when the cell to be examined is located between the rings. Each time an electron is thus trapped, the system would know that there was a dark pixel in that spot.
Eventually the level of resolution may allow scientists to view single molecules such as enzymes in action inside living cells--even single nucleic acids--the building blocks of DNA. Yanik expects that the experimental efforts as a result of this ground breaking work could lead to a prototype within the next five years.
"Noninvasive electron microscope with interaction-free quantum measurements", B. Putnam, M. F. Yanik, Phys. Rev. - Rapid Communications.