Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cellular scale drug delivery from the inside out

30.03.2006


Mesoporous nanospheres focus of Ames Laboratory research



Delivering a dose of chemotherapy drugs to specific cancer cells without the risk of side affects to healthy cells may one day be possible thanks to a nanoscale drug delivery system being explored by researchers at the U.S. Department of Energy’s Ames Laboratory.

Using tiny silica particles call mesoporous nanospheres to carry drugs inside living cells, Ames Laboratory chemist Victor Lin is studying different methods to control whether or not the particle delivers its pharmaceutical payload.


“First, the nanospheres are only about 200 nanometers in diameter, roughly the size of a virus, so they won’t trigger an immune response in the body,” Lin said. “They’re also biocompatible so they can be readily absorbed by the cells.”

But it’s the structure of the nanospheres that makes drug delivery possible. The spheres have thousands of parallel channels running completely through them. Through capillary action, the spheres can soak up molecules of the drug to be delivered. When the channels are filled, the ends of channels are “capped” to safely seal the drug inside. Once the caps are in place, the nanospheres are “washed” to remove the drug from the outer surface.

The type of material used for the end caps, how they’re held in place, and how they’re released is the focus of Lin’s work. The caps can be dendrimers, biodegradable polymers, genes, proteins, metallic nanoparticles, or semiconductor nanocrystals – also known as quantum dots – and are held in place by chemical bonds. Once the nanospheres are inside the target cells, a trigger is used to pop the caps off and release the drug.

“We’re looking at two levels of control,” Lin said of the trigger mechanism. “One level is to have the cell control the release and the other would be to control the release externally.”

Lin explained that the chemical bond holding the cap in place can be engineered to be unphased by chemicals present in normal cells. However, in cancer cells these chemicals, such as antioxidants, appear in much higher concentrations and would break the bonds on the caps and release the drugs. In this way, only cancer cells could be targeted with powerful chemotherapy drugs such as Taxol or doxorubicin, while the nanospheres inside the normal cells would remain capped and therefore not cause unwanted side affects by damaging healthy cells.

To achieve external control, Lin is using iron-oxide nanoparticle caps which can be manipulated by a magnetic field. In a simple demonstration of the principle, Lin holds a refrigerator magnet up to a liquid-filled glass vial containing human cervical cancer cells grown in vitro that contain nanospheres capped with iron-oxide particles. The cells slowly migrate and cluster to the side of the vial next to the magnet.

“By using a powerful magnet, we can first concentrate the nanospheres at a particular point, such as a tumor site, and then use the magnetic field to remove the caps and release the drug,” Lin said. “The advantage of using a magnetic trigger as opposed to a ultraviolet light trigger is that there’s no limit to the depth of tissue we are able to probe … think of an MRI.”

Beyond the possibilities for intercellular drug delivery, the nanospheres may provide the key to studying what takes place within a cell. Currently, scientists have difficulty introducing chemicals or genes into cells without either damaging the cell or causing a chain-reaction of events that can’t be tracked.

“With current gene therapy, it’s possible to switch genes on and off, but you don’t really know if you are affecting other parts and processes of the cell as well,” Lin said. “You may be able to get a plant cell to produce a certain desired product, but the yield may drop significantly.”

By using externally controlled nanospheres, Lin explains that it may be possible to sequentially release genes, chemical markers and other materials within cells in order to track what happens and what specific changes take place. This phase of Lin’s research ties into a larger plant metabolomics project at Ames Laboratory.

Ames Laboratory is operated for the Department of Energy by Iowa State University. The Lab conducts research into various areas of national concern, including energy resources, high-speed computer design, environmental cleanup and restoration, and the synthesis and study of new materials.

Kerry Gibson | EurekAlert!
Further information:
http://www.ameslab.gov

More articles from Materials Sciences:

nachricht A materials scientist’s dream come true
21.08.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Novel sensors could enable smarter textiles
17.08.2018 | University of Delaware

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Air pollution leads to cardiovascular diseases

21.08.2018 | Ecology, The Environment and Conservation

Researchers target protein that protects bacteria's DNA 'recipes'

21.08.2018 | Life Sciences

A paper battery powered by bacteria

21.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>