Scientists uncover new drug delivery method using nanosecond lasers and carbon nanotubes

Japanese scientists manipulated the cell membrane with carbon nanotubes and a near-infrared laser to produce a new method of drug delivery.--Courtesy of Science and Technology of Advanced Materials

Engineers and cell biologists have long used pulsed lasers to stimulate cells for gene transfection, drug injection or the regulation of gene expression. Now, Japanese scientists uncovered a new, potentially less-expensive method of delivering drugs and manipulating genes of individual cells by pairing nanosecond laser energy with carbon nanotubes.

Researchers at Kyushu University found that targeting a thin film of carbon nanotubes with a near-infrared (NIR) laser could provide a more effective way to break through the cell membrane and inject drugs. The scientists coated a dish with single-walled carbon nanotubes that absorb radiation and then pulsed the cell membranes with different levels of energy using a more economical nanosecond laser. The nanotubes acted as a buffer to minimize the intensity of the laser.

The Kyushu researchers discovered that cell membranes were either reversibly or irreversibly damaged after an NIR pulse, depending on how much energy was used. But at lower energies--about 15 microjoules per pulse--the membrane opened and the cell remained alive. The findings, published in Science and Technology of Advanced Materials, suggest that an inexpensive laser source paired with carbon nanotubes could work as well as more expensive lasers to target single cells to transfer genes or inject drugs.

"Such manipulation of a single cell of interest using a nanosecond pulse allows us to use an inexpensive laser source as a stimulus to engineer the targeted single cell for various targets such as selective gene transfection, drug injection and regulation of gene expression," lead author Naotoshi Nakashima said in the research paper. "To demonstrate the significance of our technique, transfection using a plasmid causing expression of green fluorescing protein is under investigation."

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