The development comes from the Korea Advanced Institute of Science and Technology, produced by a research team led by Professor YongKeun Park. Professor Park has created a device that can exert a micro-scale force upon microscopic particles. The force allows the particles to be manipulated three-dimensionally into any position. This is achieved through the use of a highly-focused laser. The beam diameter is smaller than one micrometer (equivalent to 1/100 of the thickness of a human hair).
The laser can produce an attractive force on any microscopic particles that move towards the beam focus. By varying the positions of the beam focus, the scientists can hold the particles together. Once trapped in the beam (a little like a tractor beam) the particles can be moved to other locations. Due to this ability to use laser light to control movement, the term “optical tweezers,” was adopted.
While trapping spherical particles has become straightforward, the advance that Professor Park has achieved is with capturing irregular shapes, like cells. To manipulate cells, Controlled Environments reports, the fist step is to measures the structure of an object in real time from analysis undertaken with a 3-D holographic microscope.
Once measured, the scientists can calculate the shape of light needed to control the object. By altering the light shape so it matches the object shape, the energy of the object is minimized and this traps the object. This process has been given the name “tomographic mold for optical trapping (TOMOTRAP).” In trials, the researchers have trapped and manipulated human red blood cells stably. The next step is to apply the process to studying cancerous cells.
More details can be seen in the following video:
The research findings are published in the journal Nature Communications. The research paper is titled “Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3D refractive index maps.”
