Noninvasive Electron Microscopy

clipped from web.mit.edu

To peer inside a living cell

Quantum mechanics could help build ultra-high-resolution electron microscopes that won't destroy living cells, according to MIT electrical engineers.

Electron microscopes are the most powerful type of microscope, capable of distinguishing even individual atoms. However, these microscopes cannot be used to image living cells because the electrons destroy the samples.

Now, MIT assistant professor Mehmet Fatih Yanik and his student, William Putnam, propose a new scheme that can overcome this limitation by using a quantum mechanical measurement technique that allows electrons to sense objects remotely. Damage would be avoided because the electrons would never actually hit the imaged objects.

clipped from www.rle.mit.edu

High-Throughput Neurotechnology Group

ABOUT THE GROUP
The RLE High-Throughput Neurotechnology Group is working towards development and applications of technologies for studying cellular processes. Nerve regeneration and degeneration is being studied by femtosecond laser nano-surgery and multi-photon imaging as well as large scale screening techniques. Other problems being investigated include single molecule dynamics in microfluidic devices, and sub-diffraction limit imaging in live cells. The group is also investigating photonic nano-structures for bio-sensing, nano-manipulation and bio-spectroscopy purposes.

clipped from www.rle.mit.edu

clipped from www.rle.mit.edu

"Noninvasive electron microscope with interaction-free quantum measurements", B. Putnam, M. F. Yanik, Phys. Rev. - Rapid Communications.

clipped from www.rle.mit.edu

Mehmet F. Yanik

Robert J. Shillman Assistant Professor of Electrical Engineering

Sources:

1. To peer inside a living cell
2. Research Laboratory of Electronics at MIT
3. RLE :: High-Throughput Neurotechnology Group
4. Research Laboratory of Electronics at MIT

Related:

1. Peering Inside a Living Cell
2. To Peer Inside A Living Cell: Quantum Mechanics Could Help Build Ultra-high-resolution Electron Microscopes
3. MIT EECS - Announcement Full Announcement
4. To peer inside a living cell

Optoelectronic Tweezers for Dynamic Cell Manipulation

Clipped from: 07.20.2005 - Engineers create optoelectronic tweezers to round up cells, microparticles

Engineers create optoelectronic tweezers to round up cells, microparticles

BERKELEY – Rounding up wayward cells and particles on a microscope slide can be as difficult as corralling wild horses on the range, particularly if there's a need to separate a single individual from the group.

But now, a new device developed by University of California, Berkeley, engineers, and dubbed an "optoelectronic tweezer," will enable researchers to easily manipulate large numbers of single cells and particles using optical images projected on a glass slide coated with photoconductive materials.

Clipped from: IPL: Integrated Photonics Laboratory

The working principle behind optoelectronic tweezers is light-induced dielectrophoresis. A photosensitive device layer forms "virtual electrodes" upon exposure to light, creating non-uniformities in an applied electric field (Fig. 1). The non-uniform electric field gives rise to a force known as dielectrophoresis: micro- and nanoparticles move as a result of the non-uniformities in the electric field imparting unequal forces on the induced dipole of the particle.

Figure 1:Device structure used in optoelectronic tweezers (OET).

Clipped from: Lab on a Chip Articles

Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media

Hsan-yin Hsu, Aaron T. Ohta, Pei-Yu Chiou, Arash Jamshidi, Steven L. Neale and Ming C. Wu

Clipped from: Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in ..... (DOI: 10.1039/b906593h)

Optoelectronic tweezers (OET), based on light-induced dielectrophoresis, has been shown as a versatile tool for parallel manipulation of micro-particles and cells [...] However, the conventional OET device cannot operate in cell culture media or other high-conductivity physiological buffers [...] In this paper, we report a new phototransistor-based OET (Ph-OET). Consisting of single-crystalline bipolar junction transistors, the Ph-OET has more than 500× higher photoconductivity than amorphous silicon.[...]

Fig. 6 Schematic of the Ph-OET device. Samples are placed in between an ITO-coated glass and the Ph-OET. AC electric field bias is applied between the top ITO electrode and bottom silicon substrate. Optical access is provided through the ITO glass.

Fig. 13 Spatial control of two cells. (a) Initially, two cells in close proximity are trapped in a single optical box. (b) Separation of the two adjacent cells. (c) Joining of two separated cells. (d–e) Stacking of 2 cells vertically in one single trap.

Clipped from: YouTube - Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media

Sources:

1. 07.20.2005 - Engineers create optoelectronic tweezers to round up cells, microparticles
2. IPL: Integrated Photonics Laboratory
3. Lab on a Chip Articles
4. Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in ..... (DOI: 10.1039/b906593h)
5. YouTube - Phototransistor-based optoelectronic tweezers for dynamic cell manipulation in cell culture media

Related:

1. NDC: Center for Cell Control
2. NDC: Nanomedicine Development Centers
3. Laser gadget plays Pong with cells - tech - 16 September 2009 - New Scientist
4. Berkeley Sensor & Actuator Center
5. -> Home -> Projects -> Table of all Projects