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April 06, 2007

Magnetically assembled Nanotube-Tipped Probe Developed

Improved cell by cell analysis is made possible as well as injecting drugs into active cells one at time. This development could be combined with improved versions of surgical microbots to achieve something very similar to the vision of nanobot cellular repair nanomedicine.

Drexel University College of Engineering researchers have successfully developed carbon nanotube-tipped pipettes that could become key to cell biology in-situ DNA sequencing and organelle-targeted drug delivery. This development makes it possible to perform injections or probe the fluid, not just inside a cell, but in specific regions inside the cell, maybe even specific organelles. The probe has the possibility of transferring fluids through the carbon nanotube (CNT) into and out of the pipette, thereby bridging the gap between existing microscale technologies and nanoscale interactions.


“The pipettes enable DNA to be examined inside a living cell without removing the cell from the living tissue,” he said. “This avoids culturing and/or damaging the tissue.” And the probes can aid in identifying separate drug reactions in cells. “Instead of flooding an entire cell with a drug under investigation, the drug interaction and effects with specific regions of the cell can be investigated,” he said. “Since the CNT tips have diameters smaller than some cells, small amounts of drugs can be injected to specific regions organelles within a cell.”


The Drexel researchers describe nanotube probes strong enough to pierce the wall of canine kidney cell membranes. They observed negligible cell deformation, even after removing the probe from the cell 20 minutes later. With this capability, carbon nanotube-tipped pipettes could become vital to in-situ DNA sequencing and organelle-targeted drug delivery.

The team’s method uses magnetic CNTs and an external magnetic field to align the nanotubes and assemble the probes. Joshua Freedman, a NSF IGERT Fellow working with Drs. Fontecchio and Friedman, injected a solution of magnetic CNTs and optical glue into a glass pipette and used magnet CNT by polymerizing the optical glue with UV light. They demonstrated that the resulting carbon nanotube-tipped pipette was mechanically robust to perform cell injection and could transfer fluid into the pipette

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