Chemical biology news from across RSC Publishing.
Plastic coats wrap up gene delivery
25 April 2008
UK chemists have used smart polymers to deliver DNA into cells. Based on pH-sensitive poly(ethylene glycol) (PEG) lipids, the polymers can be used as a removable protective coat for gene delivery systems.
Gene delivery systems, or vectors, have to protect their DNA cargo from enzymes, cross cell membranes and yet still release a therapeutic dose of intact DNA inside the target cell. Viral vectors can deliver genes into cells, however, they can provoke an immune response which limits their therapeutic use. One of the problems often associated with non-viral gene delivery systems is that 'the efficiency is too low and that the vectors are not sufficiently stable, particularly in vivo,' says Helen Hailes a reader in chemical biology at University College London, UK.
The PEG (yellow) shields the DNA until it is removed by acid cleavage at the linker site (blue)
The team demonstrated the new system's effectiveness by transferring DNA coding a bioluminescent enzyme into different cell types, and measuring the enzyme's activity. 'The PEG lipids seem to provide cell specific properties,' comments Antonio Villaverde, an expert in non-viral gene therapy at the Autonomous University of Barcelona, Spain. 'This could be an interesting element to favour cell targeting in delivering such constructs.'
Looking to the future, Hailes says that the team hopes to 'design different tunable features into the lipids for a range of delivery applications.' She adds that this could include using the system to deliver small interfering RNA - short strands of RNA that can be used to interfere with gene expression.
Link to journal article
Acid cleavable PEG-lipids for applications in a ternary gene delivery vector
John B. Wong, Stephanie Grosse, Alethea B. Tabor, Stephen L. Hart and Helen C. Hailes, Mol. BioSyst., 2008, 4, 532
Also of interest
Synthesis and enzymatic stability of PEGylated oligonucleotide duplexes and their self-assemblies with polyamidoamine dendrimers
Mahmoud Elsabahy, Mingzhen Zhang, Shao-Ming Gan, Karen C. Waldron and Jean-Christophe Leroux, Soft Matter, 2008, 4, 294
Canadian scientists have taken a fresh look at the processes behind DNA delivery into cells.