A promising approach to gene therapy involves short DNA fragments (interfering RNA) that bind to specific genes and block their “translation” into the corresponding, disease-related protein. A stumbling block has been the efficient and targeted delivery of RNA into the cells. Researchers led by Hongjie Dai at Stanford University have chosen to use carbon nanotubes as their “means of transport”.
This has allowed them to successfully introduce RNA fragments that “switch off” the genes for special HIV-specific receptors and co-receptors on the cells’ surface into human T-cells and primary blood cells. This leaves few “entry hatches” for the HIV viruses. The researchers report in the journal Angewandte Chemie that this allows for much better silencing effect to the cells than current transport systems based on liposomes.
T-cells are one of the types of white blood cells important for a good immune defense; they detect and destroy virus-affected cells. However, they themselves are among the targets attacked by HIV. In order to enter into a T-cell, the virus must first dock to a receptor known as CD4. Also involved is the co-receptor CXCR4. The use of short interfering RNA strands allows the CD4 and CXCR4 genes of the T-cell to be shut off. The T-cell then strops producing these receptors and the virus cannot find any points of attack on the surface of the cell. This could significantly slow down an HIV infection, as previous work have shown.
But how to get the RNA fragments into the T-cells? The shells of nonpathogenic viruses can be used to smuggle genetic material into cells, but this is dangerous in therapeutic applications because they can trigger allergies. Liposomes, tiny bubbles of fat, are safe but have proven to be ineffective for use in T-cells. Dai and his co-workers have tested a new transport system: carbon nanotubes are known for their abilities to be absorbed by cells and to smuggle other molecules in at the same time. The researchers attached phospholipids—molecules from which cell membranes are also made—to chains of polyethylene glycol. The phospholipids nestle securely onto the outer wall of the carbon nanotubes while the polyethylene glycol chains protrude into the surrounding solution. The required RNA molecules were fastened to the ends of these chains. Once inside the cell, the RNA could easily be split off by means of a sulfur–sulfur bridge.
Author: Hongjie Dai, Stanford University (USA), http://www.stanford.edu/dept/chemistry/faculty/dai/
Title: siRNA Delivery into Human T Cells and Primary Cells with Carbon-Nanotube Transporters
Angewandte Chemie International Edition 2007, 46, No. 12, doi: 10.1002/anie.200604295
Hongjie Dai | Angewandte Chemie
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy