Testing the effects of drugs on individual cells can be a complicated process since cells have evolved mechanisms to prevent intrusion of unwanted chemicals. Scientists often grow cells on top of the compounds to be tested, but whether the cells uptake them is a hit and miss proposition.
Researchers at Norwegian University of Science and Technology have been developing a bed of nano needles that can be used to inject chemicals directly into cells. The compounds to be tested are applied to the tips of the needles and cells are positioned on top. The technique still has a way to go since some of the cells are happy to be impaled and readily absorb the drugs being tested, while others tend to grow around the needles.
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The researchers create the nano-needles in a small ceramic oven. In goes something that looks like aluminium foil with a small burnt patch on it (which is actually a wafer-thin piece of copper), and two hours later at 500 degrees, the copper reacts with oxygen in the heat, creating copper oxide.
The final product looks like grey grass under the microscope, but the grass is actually the nano-needles. The next step is to put something similar to tallow onto the needles so that they can be removed from the copper plate. Glass is glued to the bottom, so that everything is transparent. The finished product looks like a small, round bed of nails. Researchers can now put cells on top of the nano-needles, and see if test drugs can be injected into cells.
But some cells are trying to fool scientists. While some cells readily impale on the nano-needles, others encapsulate the needles and grow around them.
“We are currently working on finding the correct methods to insert the needles, to ensure that all of the cells are impaled,” says Sikorski.
Press release: Nano-needles for cells