Nano technique allows precise injection of living cells

Specialized pulsed lasers have been used to inject individual cells with a variety of materials, but little is known about how this type of injection might affect living cells. For the first time, researchers at Rensselaer Polytechnic Institute have analyzed this nanoscale injection process on living cells and discovered that minor changes in the intensity of the laser could mark the difference between a healthy cell and a dead one. The findings will be presented by lead researcher Ingrid Wilke, assistant professor of physics at Rensselaer, at the World of Photonics Congress in Munich, Germany on June 20, 2007. The research originally appeared in the April 2007 edition of Physical Review E. Human illness begins and advances at the cellular level. Understanding how materials like proteins or drug ingredients affect an individual cell can give researchers important insight into how that material might impact the entire human body, according to Wilke. This makes discoveries at the cellular level extremely important. The new findings could serve as a set of guidelines for future research that requires precise microinjection of live single cells. Such research ranges from testing drugs for toxicity to targeting tumor cells with chemotherapy. “The technique will allow researchers to use unprecedented precision to microinject cells or even perform nanosurgery on cells,” Wilke said. “The problem with previous methods of single-cell injection was low cell viability and low efficacy,” Wilke said. Other physical microinjection methods are greatly hindered in living cells by the natural protective shield encasing mammalian cells. Breaking through this strong, microscopic fortress while still keeping the cell alive and undamaged has proven extremely difficult. The researchers used tightly focused femtosecond laser beam pulses that created a pore or opening in the cellular wall of living cells and encouraged the cell to take in different molecules. The laser beam serves as a “needle” that punctures... Whole article: "http://physorg.com":[ http://physorg.com/news101051071.html]

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