Nanoneedles and Nanodots...

Scanning electron mictographs of a uniform array of conical Polysilicon nanoneedles, with a < 100nm tip diameter, 600nm base diameter, 5 micron length and 2 micron pitch (Courtesy ACS Nano).

Topics: Biology, Nanotechnology, Photolithography, Quantum Dots

Biocompatible silicon nanoneedles, which can efficiently deliver nucleic acids and nanoparticles into biological cells without damaging them, have been developed by an international team of researchers. The porous needles are capable of delivering these drugs into live cells that are normally difficult to penetrate, and the technique could help damaged organs and nerves to repair themselves, and could also act as intracellular pH sensors.

The researchers, based at Imperial College London and the Houston Methodist Research Institute in Texas, made their nanoneedles using photolithography techniques. The structures can be patterned onto standard silicon chips in different ways, and the length and width of the needles can also be adjusted. Because they are porous, they can be made to take up a significantly greater amount of nucleic acid, nanoparticles and other therapeutics. Importantly, the porous silicon from which they are made is biocompatible – unlike ordinary silicon – and it clears the body in about two days, without leaving behind any toxic residue.

The plasma membrane and "endo-lysosomal compartment" of a cell are major biological barriers that limit the therapeutic efficiency of many drug-delivery vehicles by preventing nanostructures from entering the cells. According to team member Ennio Tasciotti from the Department of Nanomedicine at the Houston Methodist Research Institute, the new nanoeedles can "successfully deliver nucleic acids into cells, bypassing their plasma membrane and endo-lysosomal compartments without damaging the cell".

Physics World: Silicon 'nanoneedles' deliver nanodots and nucleic acids, Belle Dumé