Imagine being able to drop a toothpick on the head of one particular person standing among 100,000 people in a stadium. It sounds impossible, yet this degree of precision at the cellular level has been demonstrated by researchers affiliated with the Johns Hopkins University Institute for NanoBioTechnology. Their study was published online in June in Nature Nanotechnology.
The team used precise electrical fields as "tweezers" to guide and place gold nanowires, each about one-two hundredth the size of a cell, on predetermined spots, each on a single cell. Molecules coating the surfaces of the nanowires then triggered a biochemical cascade of actions only in the cell where the wire touched, without affecting other cells nearby. The researchers say this technique could lead to better ways of studying individual cells or even cell parts, and eventually could produce novel methods of delivering medication.
Indeed, the techniques not relying on this new nanowire-based technology either are not very precise, leading to stimulation of multiple cells, or require complex biochemical alterations of the cells.
With the new technique the researchers can, for instance, target cells that have cancer properties (higher cell division rate or abnormal morphology), while sparing their healthy neighbors.
"One of the biggest challenges in cell biology is the ability to manipulate the cell environment in as precise a way as possible," said principal investigator Andre Levchenko, an associate professor of biomedical engineering in Johns Hopkins' Whiting School of Engineering. In previous studies, Levchenko has used lab-on-a-chip or microfluidic devices to manipulate cell behavior. But, he said, lab-on-a-chip methods are not as precise as researchers would like them to be. "In microfluidic chips, if you alter the cell environment, it affects all the cells at the same time," he said.
Such is not the case with the gold nanowires,
|Contact: Mary Spiro|
Johns Hopkins University