21 January 2008
New Delivery Method For Gene Therapy
by Kate Melville
Gene therapy theoretically makes it possible to introduce genes into cells to cure disease or address deficiencies in biological processes. But in order for gene therapy to work, foreign (or synthetic) DNA must be introduced into host cells, which is a non-trivial task.
Traditionally, researchers inserted foreign DNA through the cell membrane which had been made porous through treatment with electrical current or UV lasers. Viruses and liposomes have also been used as genetic transporters with limited success. Both methods have the disadvantage of either severely damaging delicate cells or of being markedly expensive and complicated.
Now, however, Japanese researchers have developed a method which could represent a true alternative to conventional gene transfer processes. Described in the journal Angewandte Chemie, the new method "bombards" the cells with water droplets produced and accelerated electrically.
Lead researcher Takafumi Sakai, from Saitama University, explained that the tiny electrically charged water droplets tear miniscule holes in the cell membranes, through which external DNA molecules can enter. After about one minute, the holes have closed back up and even delicate cells survive the procedure undamaged.
The method is based on a technique called "electrospray", where the tip of an extremely fine steel capillary is put under a high voltage. A highly charged drop of water exits the capillary and is atomized into many micro- or nanoscopic droplets. These charged microdroplets are strongly accelerated in an electrical field toward the plate holding the cell culture.
The researchers say the new method works with a large variety of cell types - including mammalian cell cultures and bacteria, as well as living tissue. No cytotoxic reagents that could damage the cells are needed; only pure water or a cell-tolerated saline solution are used. An entire plate of cell cultures can be "sprayed" bit by bit, or a specific point on some tissue can be targeted. Most importantly, the researchers noted, the equipment needed is simple, inexpensive and portable.
Source: Angewandte Chemie